Non-technical Summary
Brachyurans or true crabs are a dominant group of arthropods in modern ecosystems with a long fossil record. High diversity settings (hot spots) yielding crabs include modern reefs like those from the Indo-Pacific and the Caribbean. Understanding ancient reef-like hot spots is challenging especially because they have some physical environmental conditions (high energy, low sedimentation rates) that do not favor preservation. The Ramals outcrop in the Eocene Serraduy Formation (about 53 million years old) of Huesca, northeastern Spain is an exception, and it hosts a great diversity of invertebrates including decapod crustaceans. Herein we report from this exceptional locality 15 new or first-reported taxa of brachyurans including three new genera, ten new species, and five taxa in open nomenclature. Some of the crab taxa are the first ones reported in Spain and some represent the oldest occurrence of modern families of crabs.
Introduction
Modern coral reef ecosystems, which are among the most diverse habitats globally (Moberg and Folke, Reference Moberg and Folke1999; Roberts et al., Reference Roberts, McClean, Veron, Hawkins and Allen2002; Knowlton et al., Reference Knowlton, Brainard, Fisher, Moews, Plaisance, Caley and McIntyre2010; Hurley et al., Reference Hurley, Timmers, Godwin, Copus, Skillings and Toonen2016), were fully established by the Eocene (Pomar et al., Reference Pomar, Baceta, Hallock, Mateu-Vicens and Basso2017). Modern mesophotic coral reefs, like those found in the Serraduy Formation, occur in the deeper parts of the photic zone, ranging from 30 to 150 meters in depth (i.e., Hinderstein et al., Reference Hinderstein, Marr, Martinez, Dowgiallo, Puglise, Pyle, Zawada and Appeldoorn2010; Hurley et al., Reference Hurley, Timmers, Godwin, Copus, Skillings and Toonen2016).
Fossil invertebrates from these habitats are difficult to sample and quantify especially because they usually are subjected to taphonomic conditions that do not favor preservation (Klompmaker et al., Reference Klompmaker, Hyžný and Jakobsen2015). Decapod crustaceans from the coral reef mounds from the Serraduy Formation are an exception, because facies distribution and general transgressive trends with rapid sedimentary pulses favored preservation of reef inhabitants, which were transported to and accumulated in the forereef facies (Ferratges et al., Reference Ferratges, Zamora and Aurell2021a). Consequently, 44 taxa of decapod crustaceans have been preserved in different states of preservation (Artal and Vía, Reference Artal and Vía1989; Artal and Castillo, Reference Artal and Castillo2005; Artal and Van Bakel Reference Artal and van Bakel2018a, Reference Artal and van Bakelb; Ferratges et al., Reference Ferratges, Zamora and Aurell2019, Reference Ferratges, Zamora and Aurell2021a, Reference Ferratges, Domínguez and Ossób, Reference Ferratges, Artal, van Bakel and Zamora2022; Artal et al., Reference Artal, Ferratges, van Bakel and Zamora2022; Ferratges, Reference Ferratges2022; Table 1).
Updated table with Ramals outcrop decapod crustacean diversity. Species in bold are described in this work or recognized for the first time; *taxa only known in this outcrop as isolated chelipeds
Two previous contributions focused on the study of dromioid crabs (Artal et al., Reference Artal, Ferratges, van Bakel and Zamora2022) and paguroids (Ferratges et al., Reference Ferratges2022). However, heterotrematous crabs are the most diverse group of decapods and remained undescribed (Table 1). This paper focusses on the descriptions of new and newly reported species of brachyurans (excluding Raninoidea).
True crabs or brachyurans are ubiquitous members of modern reef communities and are present in many trophic niches (Plaisance et al., Reference Plaisance, Caley, Brainard and Knowlton2011), being among the most representative groups in benthic communities (Hurley et al., Reference Hurley, Timmers, Godwin, Copus, Skillings and Toonen2016). Many of the modern families of crabs originated at least in the Eocene (i.e., Brösing, Reference Brösing2008; Tsang et al., Reference Tsang, Schubart, Ahyong, Lai, Au, Chan, Ng and Chu2014; Schweitzer and Feldmann, Reference Schweitzer and Feldmann2015). Thus, the present work provides additional taxa informing about the first occurrence of the genera Carpilius, Ceronnectes, Eohexapus, Galenopsis, Parhalimede, Liocarcinus, Alponella, and Lovaroides.
Locality, material, and methods
Locality
The material described herein was collected from the early Eocene (middle Ypresian) Serraduy Formation of the Tremp-Graus Basin. The material was collected from an outcrop that exposes the transition between the reef limestones and the overlying Riguala Marls at a locality known as “Barranco de Ramals” (see Ferratges et al., Reference Ferratges, Zamora and Aurell2021a, for further information). All specimens were collected from the same levels described in Ferratges et al. (Reference Ferratges, Zamora and Aurell2021a, Reference Ferratges2022) and Artal et al. (Reference Artal, Ferratges, van Bakel and Zamora2022), to which further reference is made.
Material
More than 1000 specimens of brachyuran crabs (357 in MPZ and about 700 in MGSB) that have been revised from the studied outcrop belong to 20 genera and species (included in 15 families), 14 of which are new or reported for the first time, with 10 new species formally named (Table 1). The specimens were prepared physically using a Micro Jack 2 air scribe (Paleotools; Brigham, UT, USA) and prepared chemically in some cases using potassium hydroxide (KOH). The specimens were then photographed dry and coated with ammonium chloride sublimate. Detailed photography of the carapace surfaces was made using a Nikon d7100 camera (Nikon, Tokyo, Japan) with a macro, 60-mm lens.
Repositories and institutional abbreviations
The specimens are deposited in the Museo Geológico del Seminario de Barcelona (MGSB) and the Museo de Ciencias Naturales de la Universidad de Zaragoza (MPZ). The material deposited in MPZ was collected under permit EXP: 032/2018 from the Servicio de Prevención, Protección e Investigación del Patrimonio Cultural (Gobierno de Aragón). The material deposited in MGSB was collected in the early 1980s and is housed within the historical collection of the Seminario Conciliar de Barcelona.
Systematic paleontology
Order Decapoda Latreille, Reference Latreille1802
Infraorder Brachyura Latreille, Reference Latreille1802
Section Eubrachyura de Saint Laurent, Reference de Saint Laurent1980
Superfamily Aethroidea Dana, Reference Dana1851
Family Aethridae Dana, Reference Dana1851
Genus Ilerdapatiscus Artal and van Bakel, Reference Artal and van Bakel2018a
Type species
Ilerdapatiscus guardiae Artal and van Bakel, Reference Artal and van Bakel2018a, by original designation.
Ilerdapatiscus guardiae Artal and van Bakel, Reference Artal and van Bakel2018a
(1–7) Ilerdapatiscus guardiae Artal and van Bakel, Reference Artal and van Bakel2018a, MPZ 2021/39 in dorsal (1), ventral (2), and frontal (3) views; (4) MGSB 77611 ventral view with sternum; (5, 6) MGSB 75462 (6) dorsal view with chelipeds, (7) right cheliped in oblique lateral view; (7) MGSB 75462 left cheliped in oblique frontal view.
Reference Artal and van Bakel2018a Ilerdapatiscus guardiae Artal and van Bakel, p. 5, fig. 1-2.
Reference Ferratges, Zamora and Aurell2021a Ilerdapatiscus guardiae; Ferratges et al., p. 11, fig. 7L.
Holotype
A complete carapace (MGSB 75460).
Emended diagnosis
Modified from the original diagnosis of Artal and van Bakel (Reference Artal and van Bakel2018a). Carapace subcircular, broader than long; maximum width in anterior portion; front narrow, with small medial incision, marked axial depression; orbits small, with two small supraorbital fissures; anterolateral margins arched, with seven small lobes; posterolateral margins convex, bearing notable hemispherical mesobranchial swelling and small metabranchial node; posterior margin concave, shorter than frontal margin; dorsal surface with eight hemispherical swellings; three gastric, four branchial, and one cardiac; mesobranchial region with hemispherical swelling situated at posterolateral margin. Sternum narrow, transversely subelliptical. Sterno-pleonal cavity narrow; sternites 1–4 fused, subtriangular, with protruding episternite 4; sternites 7–8 extremely narrow. Chelipeds homochelous, robust, external side of palm covered by rows of tubercles.
Material examined
Forty-six specimens in MPZ and 75 in MGSB. Specimen MGSB 77611 preserves ventral portions. Measurements: W 20 mm, L 21 mm. Specimen MGSB 75462 with attached cheliped.
Remarks
Recently prepared specimens showing ventral features allow the original diagnosis to be emended to include ventral aspects. These ventral features confirm assignation to Aethridae (see Ng et al., Reference Ng, Guinot and Davie2008, p. 44–45; Beschin and De Angeli, Reference Beschin and De Angeli2017, p. 24). Some isolated chelipeds (Fig. 1.5, 1.6) have been assigned to this taxon based on a partially articulated specimen, a carapace with attached remains of chelipeds, and the similarity of these chelipeds to those of other fossil genera assigned to the Aethridae (i.e., Vía, Reference Vía1959; De Angeli and Beschin, Reference De Angeli and Beschin1999; Beschin and De Angeli, Reference Beschin and De Angeli2017).
Superfamily Cancroidea Latreille, Reference Latreille1802
Family indet.
Genus Locomius new genus
Type species
Locomius parthenopimimus n. gen. n. sp., by monotypy.
Diagnosis
As for the type species, by monotypy.
Etymology
The name refers to its fan shape, which calls to mind the 1980s pop music group “Locomia”, in arbitrary combination of letters. Gender masculine.
Remarks
Locomius n. gen. shows certain morphological characteristics that seem typical of cancroids, including a subhexagonal outline of the carapace, being wider than long; the front with protruding teeth; raised orbits, with two notable supraorbital fissures; arched anterolateral margins; anterolateral margins divided into flat lobes separated by notches; strongly concave posterolateral margins converging backwards; dorsal regions well defined by swellings (Schram and Ng, Reference Schram and Ng2012; Schweitzer and Feldmann, Reference Schweitzer and Feldmann2019; Karasawa and Takahashi, Reference Karasawa and Takahashi2020; Poore and Ahyong, Reference Poore and Ahyong2023).
Some fossil genera that present characteristics very similar to Locomius n. gen., including Eogarthambrus De Angeli, Garassino, and Alberti, 2010, and Mesolambrus Müller and Collins, Reference Müller and Collins1991 (see Schweitzer et al., Reference Schweitzer, Feldmann and Karasawa2020), have been assigned to the family Parthenopidae due to their subtriangular morphology, but parthenopids have a strongly differentiated frontal margin, and differentiated fronto-orbital margin. In the case of Eogarthambrus, the only difference is the much wider outline of the carapace and the presence of four broad and armed teeth in the anterolateral margin, and the orbits directed more obliquely (see De Angeli, Garassino, and Alberti, Reference De Angeli, Garassino and Alberti2010, fig. 1-3). Recently, Ferratges et al. (Reference Ferratges, Luque, Domínguez, Ossó, Aurell and Zamora2023b) carried out a phylogenetic analysis to clarify parthenopoid relationships, which included several fossil taxa traditionally assigned to this group. The results obtained suggested that taxa very similar to Locomius n. gen., such as Eogarthambrus, might be included within Cancroidea. We follow that classification.
Locomius parthenopimimus new species
Idealized reconstruction of the carapace of Locomius parthenopimimus n. gen. n. sp.
(1–5) Locomius parthenopimimus n. gen. n. sp. (1, 2) Holotype (MGSB 77604) in dorsal (1) and (2) frontal views; (3) lateral view of paratype MGSB 77605a; (4, 5) MPZ 2024/80 right cheliped (specimen), in lateral view of outer side (4) and inner side (5). (6–9) Ceronnectes rugosus n. sp. in dorsal (6), left lateral (7), and frontal (9) views of paratype (MGSB 77592) and dorsal view (8) of holotype (MGSB 88653).
Type material
Five specimens, the holotype, a complete carapace, is MGSB 77604; and four paratypes: MGSB 77605a–c and MPZ 2021/35.
Diagnosis
Sub-hexagonal carapace, wider than long, L/W ratio about 0.8, steeply downturned anteriorly; quadrilobed front, with two medial protruding teeth; small orbits, slightly obliquely directed, raised supraorbital margin, with two deep fissures; anterolateral margin with four lobes flattened dorsoventrally; concave posterolateral margins, convergent; strongly swollen dorsal regions, well defined by shallow grooves and raised swellings.
Description
Carapace subhexagonal, fan-shaped in outline, wider than long, L/W ratio about 0.8, maximum width at 3/4 of its length; dorsal surface longitudinally convex, steeply downturned anteriorly. Front with four lobes, narrow, slightly extended beyond orbits, with four lobes and median incision, the two medial more protruding, with blunt tip and directed forward. Orbits elliptical, anterolaterally directed, orbital margin markedly raised, with two supraorbital indentations; outer-orbital spine not well developed. Fronto-orbital margin occupying about 45% of the maximum width of carapace. Anterolateral margins broadly convex, with four dorso-ventrally flattened lobes separated by fissures. Posterolateral margins shorter, concave, connecting to anterolateral margins by acute angle. Posterior margin short, nearly straight. Dorsal regions strongly swollen and raised, subdivided in portions and bounded by shallow grooves. Epigastric region small, defined by elongated ridges. Protogastric and mesogastric regions large, strongly swollen and raised. Hepatic region small, depressed, only covered with irregular granules. Epi- and mesobranchial regions differentiated, defined by oblique swellings. Cardiac region large, elongated, subpentagonal in shape. Dorsal grooves numerous, most of them shallow, the branchiocardiac groove deep. Dorsal surface of carapace strongly ornamented, densely covered by small granules and irregular tubercles. Manus of cheliped short; lateral surface with three granular ridges and scattered tubercles; upper margin with four short spines; ventral margin concave. Fingers short and robust. The chelae tentatively assigned to this taxon are robust, with divergent upper and lower margins, five strong spines in the upper margin; outer surface with three tubercles and three subtle longitudinal ridges; inner surface smooth (Fig. 4.4, 4.5).
Carpilius feldmanni n. sp. (1–3) holotype (MPZ 2024/82) in (1) dorsal, (2) frontal, and (3) detail of the ventral side of frontal margin. Xanthilites robustus n. sp. (4–8) holotype (MGSB 75446) in ventral (4), frontal (5), and lateral (6) views; paratype (MPZ 2021/44) in dorsal view (7); right cheliped (specimen MPZ 2024/84), in lateral view of outer side (8). (9–13) Matutsalen rotundus n. gen. n. sp. (9–11) Holotype (MGSB 75463) in dorsal (9), lateral (11), and frontal(10) views; (12, 13) right cheliped (MPZ 2021/40), (12) in lateral view of outer side and (13) oblique frontal view.
Etymology
The name “parthenopimimus” refers to the triangular morphology of the carapace, which resembles that of parthenopoids.
Other material examined
Three isolated chelipeds in MGSB, and two in MPZ (MPZ 2024/80, MPZ 2024/81).
Remarks
Locomius parthenopimimus n. gen. n. sp. shows important similarities with Eogarthambrus guinotae De Angeli, Garassino, and Alberti, Reference De Angeli, Garassino and Alberti2010; however, the carapace is less laterally expanded and in the anterolateral margin shows four teeth instead five as E. guinotae. The fossil species Ramacarcinus lineatuberculatus (Beschin, Busulini, and Tessier in Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a) from the early Eocene of Italy has a similar morphology to Locomius n. gen. with a wide frontal margin, with an incision in the middle frontal area and four lobes (including intraorbital ones); supraorbital margin rimmed, robust, granulated and with two fissures; anterolateral margins long, convex, endowed with flat teeth, separated by notches; convergent and concave posterolateral margins; short straight posterior margin; dorsal regions defined by smooth furrows ornamented with tubercles (see Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a, t.11, figs. 1a,. 44; De Angeli and Ceccon, Reference De Angeli and Ceccon2016, p. t.5–6, fig. 11). However, in the anterolateral margin, R. lineatuberculatus has five bifid or trifid teeth (excluding the extraorbital one) instead of four finely serrated teeth as in the new species Locomius parthenopimimus n. gen. n. sp.; dorsal surface with different ornamentation, and not distributed in alignments.
Family Cancridae Latreille, Reference Latreille1802
Genus Ceronnectes De Angeli and Beschin, Reference De Angeli and Beschin1998
Type species
Cancer böckhii Lőrenthey, Reference Lőrenthey1897, by original designation.
Fossil species included
Ceronnectes boeckhi (Lőrenthey, Reference Lőrenthey1897), C. granulosa (Feldmann et al., Reference Feldmann, Bice, Hopkins, Salva and Pickford1998, ?C. pusillinus (Secrétan in Plaziat and Secrétan, Reference Plaziat and Secrétan1971), and C. rugosus n. sp.
Ceronnectes rugosus new species
Type material
Two almost complete carapaces, one holotype (MGSB 88653) and one paratype (MGSB 77592).
Diagnosis
Carapace subhexagonal, L/W ratio 0.85 maximum width at level of last anterolateral spine, about two-thirds of carapace length; dorsal regions delimited by grooves; surface ornamented with small irregular granules. Orbits broad, with two weak supraorbital fissures. Anterolateral margins arched, with four irregular, flattened lobes.
Description
Carapace subhexagonal, with fan-shaped outline; longitudinally slightly vaulted, somewhat more vaulted transversely; wider than long, L/W ratio 0.85; maximum width at level of last anterolateral spine, about two-thirds of its length. Frontal margin not well preserved. Orbits relatively broad; supraorbital margin with two weak supraorbital fissures; outer orbital spine acute and subtriangular. Fronto-orbital margin occupying about 73% of carapace width. Anterolateral margins arched, longer than posterolateral margins, bearing four irregular, different by size, flattened lobes. Posterolateral margins nearly straight, slightly concave, very convergent posteriorly. Posterior margin narrow, not completely preserved. Dorsal regions well defined, gently swollen. Gastric process large; epigastric lobes elongated, swollen; protogastric lobes broad, swollen, delimited by shallow grooves; mesogastric region scarcely differentiated from the urogastric region, only slightly swollen, with the anterior extension relatively broad and swollen. Urogastric region weakly defined by a horizontal row of granules. Cardiac region large, swollen, barely distinct from gastric lobe, bounded by relatively deep grooves. Hepatic regions flattened, delimited from gastric regions by the gastro-hepatic groove. Epibranchial ridge arched, reaching the last anterolateral tooth. Dorsal surface of carapace covered by irregular granules, some of them unevenly grouped, conferring the appearance of a wrinkled dorsal surface.
Etymology
The specific epithet refers to the coarse texture of the dorsal carapace surface.
Remarks
The Eocene Ceronnectes boeckhi (Lőrenthey, Reference Lőrenthey1897) is the most similar taxon, but it has a more subhexagonal outline of carapace with wider appearance; orbits with two deep, well-marked supraorbital fissures; anterolateral margins with four lobes of similar size; posterolateral margins being concave, the dorsal regions more elongated; dorsal surface smoother, with absence of noticeable granules (De Angeli and Beschin, Reference De Angeli and Beschin1998; Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b, fig. 43, t. 8, f. 9). Liocarcinus Stimpson, Reference Stimpson1871, Macropipus Prestandrea, Reference Prestandrea1833, and Polybius Leach, 1829, three genera with apparently similar dorsal features and outline as Ceronnectes, have been assigned to Portunoidea (Schweitzer et al., Reference Schweitzer, Feldmann and Karasawa2021), and mainly differ by the absence of anterolateral nodes that are bounded by noticeable indentations, which is a diagnostic character in the Cancroidea.
Superfamily Carpilioidea Ortmann, 1893
Family ?Arabicarcinidae Schweitzer and Feldmann, Reference Schweitzer and Feldmann2017
Remarks
Due to the morphology of the rounded carapace, shape of the orbits, and general outline of the carapace, all of which are very similar to Eomatuta and Arabicarcinus, we tentatively assign Matutsalen n. gen. to the family Arabicarcinidae Schweitzer and Feldmann, Reference Schweitzer and Feldmann2017 (see Beschin et al., Reference Beschin, Checchi and De Angeli2019).
Genus Matutsalen new genus
Type species
Matutsalen rotundus n. gen. n. sp., by original designation.
Diagnosis
See species diagnosis.
Etymology
The generic name refers to the family Matutidae with which it shares several superficial similarities, in combination with “Matusalén” as the man who is claimed to have lived the longest life, referring to their ancestral condition. Gender masculine.
Remarks
Matutsalen n. gen. shows similarities with the fossil genus Eomatuta De Angeli and Marchiori, Reference De Angeli and Marchiori2009, in the general outline of the carapace, shape of the orbits, and front with four lobes, and narrow concave posterior margin, with one small tubercle on each side. However, Eomatuta is easily distinguished from Matutsalen n. gen. in having continuous lateral margins, without spines, the dorsal surface completely covered with dense and large granulation, and dorsal regions very slightly marked. Matutsalen n. gen. and Arabicarcinus Schweitzer and Feldmann, Reference Schweitzer and Feldmann2017, from the Coniacian Cretaceous of Saudi Arabia, exhibit similarities in the oval shape of the carapace, a front with four lobes, moderately large and subrectangular orbits, and a concave posterior margin. However, they present clear differences: Arabicarcinus has continuous lateral margins without spines, a punctate dorsal surface with low relief and poorly defined regions, sinuous orbits, and rimmed posterior margin.
The fossil genus Szaboa Müller and Galil, Reference Müller and Galil1998, included in the family Matutidae De Haan, 1835, has a very similar outline of the carapace with Matutsalen n. gen., but shows differences in the morphology of the dorsal regions, which are more marked in the new genus; the shape and size of the anterolateral spines, which are more robust in the new genus; the frontal margin without prominent tubercles in Szaboa; and the posterior margin convex instead of concave as in Matutsalen n. gen.
Matutsalen n. gen. shows morphological similarities with fossil and modern Ashtoret Galil and Clark, Reference Galil and Clark1994, and the modern genera Matuta Weber, Reference Weber1795, Izanami Galil and Clark, Reference Galil and Clark1994, and Mebeli Galil and Clark, Reference Galil and Clark1994, (all included in the family Matutidae), including: (1) general shape of the carapace with a slightly convex surface; (2) shape of the frontal margin, with front divided into four and orbits very angled in the internal supraorbital margins; (3) convexity of the anterolateral margins; and (4) narrow posterior margin. However, Matutsalen n. gen. shows strong conical spines on the anterolateral margins; lacks the long lateral spines, typical of modern genera; and lacks the smooth and porcelain appearance of modern genera, with dorsal regions well defined and granulated.
The chelipeds assigned to Matutsalen n. gen. show the typical characteristics of calappoids: laterally compressed, without ornamentation on the inner side; outer surface tuberculate; a ridge with several spines on the upper margin; and a movable finger with a molariform expansion that separates it from the base of the dactylus. Furthermore, the curvature of the inner margin of the chelipeds fits with the anterior lower part of the carapace (see Ferratges et al., Reference Ferratges, Zamora and Aurell2021a, fig. 7O; Fig. 1.10, 1.11). All these characteristics of Matutsalen n. gen. are ambiguous and its inclusion either in Calappoidea De Haan, 1833, or Carpilioidea Ortmann, Reference Ortmann1893, is problematic.
Matutsalen rotundus new species
Idealized reconstruction of the carapace of Matutsalen rotundus n. gen. n. sp.
Type material
Four specimens, the holotype, a near-complete carapace, is MGSB 75463, and three paratypes: MGSB 75464a, MGSB 75464b, and MPZ 2021/34.
Diagnosis
Carapace subcircular, convex surface, almost as wide as long; frontal margin with four lobes, orbits suboval, with two supraorbital fissures and a fissure in the infraorbital margin; lateral margins convex, with three spines and one posterior tubercle; posterior margin narrow and concave; dorsal regions well defined; the posterior two-thirds of the carapace covered by granules.
Description
Carapace almost as long as wide, subcircular shape, L/W ratio about 0.98, maximum width at one-half of its length; dorsal surface longitudinally and laterally convex, steeply downturned anteriorly; broad fronto-orbital margin, occupying 63% of the carapace width. Front narrow, extended beyond orbits, with median incision and two lobes directed slightly ventrally on each side. The middle part of the frontal region is furrowed by a longitudinal depression. Orbits large, elliptical, oriented forward; supraorbital margin raised, with two supraorbital fissures; anterolateral margins convex, with three conical spines, the first two directed anteriorly, the third oriented laterally, perpendicular to the axis. Posterolateral margins less convex than anterolateral margins; bearing a blunt spine. Narrow posterior margin, slightly concave, with a small protrusion on each side. Dorsal regions well defined by swellings and shallow grooves. Frontal region with longitudinal depression. Gastric regions swollen, elongated. Hepatic region small, with a strong protuberance. Branchial regions divided in portions, defined by oblique inflations. Cardiac region elongated. Intestinal region depressed. Dorsal surface ornamented with irregular granulations, more abundant in the posterior two-thirds (Figs. 1.7, 2). The chelipeds assigned to this genus (Fig. 1.10, 1.11) present the typical structure of the calappoids, with an expansion in the occlusal margin of dactyl. The upper margin of the propodus is provided with a highly developed crest forward oriented; outer surface of the palm is ornamented with irregular granulations; fixed finger short and turned obliquely downwards, the occlusal margin has small, rounded teeth; the dactyl is long and robust, with the upper margin decorated with granulations. Ventral parts not preserved.
Etymology
“rotundus” is given in the masculine form to agree with the gender of the genus, and refers to the rounded shape of the carapace.
Remarks
Matutsalen rotundus n. gen. n. sp. shows a morphology similar to Eomatuta granosa De Angeli and Marchiori, Reference De Angeli and Marchiori2009. However, it differs in some aspects: frontal margin divided into four lobes that are very accentuated in the new taxon; anterolateral margins of the new taxon have five teeth, the first being that of the postorbital margin; dorsal regions much more clearly defined in the new species; and dorsal surface of the new taxon mostly covered with tubercles in the posterior part and on the tips of the dorsal regions only, not homogeneously covered with rounded tubercles as in E. granosa.
Family Carpiliidae Ortmann, Reference Ortmann1893
Genus Carpilius Leach in Desmarest, Reference Desmarest1823
Type species
Cancer maculatus Linnaeus, Reference Linnaeus1758, by monotypy.
Fossil species included
Carpilius cantellii De Angeli and Alberti, Reference De Angeli and Alberti2020; C. convexus (Forskål, Reference Forskål1775) (also extant); C. corallinus (Herbst, 1783) (also extant); C. feldmanni n. sp.; C. maculatus (Linnaeus, Reference Linnaeus1758) (also extant); C. petreus Beschin et al., Reference Beschin, Busulini, De Angeli and Tessier2007.
Carpilius feldmanni new species
Type material
The holotype, a near-complete, slightly compressed carapace, is MPZ 2024/82.
Diagnosis
Carapace ovate, wider than long, vaulted longitudinally, smooth surface, with small- to medium-size pits on anterior two-thirds, poorly defined regions. Front with central bilobed projection. Circular, rimmed and smooth orbits. Convex anterolateral margin. Nearly straight posterior and posterolateral margins. Cheliped smooth, manus about as long as high; fingers short, thick, with one blunt tooth.
Description
Carapace transversely oval, vaulted, wider than long, L/W ratio 0.68; regions not defined, maximum width about two-thirds of its length. Frontal margin with four blunt lobes (quadrilobate). Orbits sub-circular; inner and outer orbital spines blunt. Fronto-orbital margin occupying about 43% of carapace width. Anterolateral margins arched, longer than the posterolateral margins, entire. Posterolateral margins nearly straight. Posterior margin narrow, rimmed. Dorsal regions not defined, only the branchiocardiac grooves are well marked. Dorsal surface with small- to medium-size pits on anterior two-thirds of the carapace. Proepistome subtriangular, with rounded apex, antennular fossettes rhomboidal.
Etymology
The specific epithet honors Dr. Rodney Feldmann, in recognition of his considerable contributions to the crustacean paleontological record.
Remarks
The general shape, dorsal ornamentation, and the main characters of the new material fit the general diagnosis of the extant and extinct Carpilius (see Schweitzer et al., Reference Schweitzer, Feldmann and Karasawa2018). However, C. feldmanni n. sp. has a narrower fronto-orbital margin, and the branchiocardiac grooves are deeper than other species. The fossil species C. petreus is slightly reminiscent of the general outline of the carapace of the new species; however, it is more rounded than that of the new species and the morphology of the frontal margin is different, more downward oriented, and with more marked protuberances in C. petreus (see Beschin et al., Reference Beschin, Busulini, De Angeli and Tessier2007, t. 5, ff. 7a, b, 8a, b, Reference Beschin, De Angeli, Checchi and Zarantonello2016b, fig. 45. t. 9, ff. 3A, B). The fossil species C. cantellii De Angeli and Alberti, Reference De Angeli and Alberti2020, from the late Eocene of Italy, can be differentiated mainly in its more rounded outline (less laterally expanded), wider posterior margin, less marked branchiocardiac grooves, and the pits of its carapace are larger and are distributed over the entire surface, unlike the new species. Carpilius feldmanni n. sp. represents the oldest record of the genus Carpilius.
Family Tumidocarcinidae Schweitzer, Reference Schweitzer2005
Genus Xanthilites Bell, Reference Bell1858
Type species
Xanthilites bowerbanki Bell, Reference Bell1858, by original designation.
Fossil species included
Xanthilites bowerbanki Bell, Reference Bell1858, X. robustus n. sp., X. interpunctus Schafhäutl, Reference Schafhäutl1863.
Xanthilites robustus new species
Reference Ferratges2017 Xanthilites bowerbanki, Ferratges, p. 53, fig. 13 B, C.
Reference Ferratges, Zamora and Aurell2021a Xanthilites sp. Ferratges et al., p 11, fig. 7S.
Type material
Four specimens, the holotype (MGSB 75446) preserves the ventral portion, and three paratypes; MGSB 75447 a–c, and MPZ 2021/44.
Diagnosis
Carapace subhexagonal, wider than long, widest at position of epibranchial node. Frontal margin downturned, straight from dorsal view, bearing four lobes. Orbits small, rimmed, with two supraorbital fissures. Anterolateral margin bearing two blunt nodes. Posterolateral margin somewhat concave. Posterior margin with thin rim. Dorsal regions well defined by gentle swellings and shallow grooves. Mesobranchial region weakly separated from posterior regions. Dorsal surface densely covered by granules. Sternum broad, subtriangular, with arched lateral margins. Sternites 3 and 4 with elongated horizontal and oblique swellings. Female pleon broad, subtriangular; telson triangular, sixth pleonal segment subrectangular, large. Coxae of pereiopods and third maxillipeds large.
Description
Carapace subhexagonal in outline, wider than long, L/W ratio about 0.77, widest at position of the last anterolateral spine, about 50% of carapace length. Carapace vaulted in both directions. Front broad, straight from dorsal view, with a small axial indentation, strongly downturned; frontal margin with four blunt lobes. Orbits small, anterolaterally directed, orbital margin rimmed, granulated. Anterolateral margins arched and shorted than posterolateral; first portion broadly arched, last portion bearing two blunt nodes. Posterolateral margins converging posteriorly, slightly concave. Posterior margin rimmed, somewhat longer than the frontal margin. Dorsal regions well defined by broad, gentle swellings and weak, shallow grooves. Epigastric regions defined by small swellings and numerous granules. Protogastric regions large, subtrapezoidal in shape. Mesogastric region large, subpentagonal, weakly differentiated posteriorly; anterior extension extremely narrow, elongated. Hepatic region slightly swollen. Epibranchial region large, slightly swollen, scarcely divided, the anterior portions of branchial region separated from the metabranchial by a shallow depression. Cardiac region somewhat swollen, subtriangular inverted in shape. Intestinal region flattened. Dorsal surface of carapace densely granulated, except the dorsal grooves and depressions, which are smooth. A well-defined hepatogastric groove runs obliquely along the carapace, merging with the gastrobranchial and the branchiocardiac grooves; the cervical groove not defined. Ventral portions of carapace narrow, elongated, with scarce granules. Pterygostomial region large, arched, devoid of granulation. Sternum large, subtriangular, with arched lateral margins. Sternites 1–2 small subtriangular, fused. Sternites 3–4 large, fused, sternite 3 horizontal swollen; sternite 4 oblique, swollen; sternite 5 scarcely visible, sternites 6–8 covered by female pleon. Episternites 4 and 5 subtriangular, well developed. Upper portion of the antennular space, below the front, strongly ridged. Basal segment of antennule subtriangular. Proepistome subtriangular, with rounded apex. Epistome robust, subrectangular, with rounded corners and medial sulcus. Buccal frame subtrapezoidal. Maxilipeds 3 large, stout, endopod with elongated sulcus in the middle, exopod long, narrow. Sternopleonal cavity large, relatively deep. Female telson large, subtriangular; pleonal segment 6 subrectangular, large, pleomeres 3–5 free, narrow. Coxae of pereiopods large, subrectangular. Chela short robust, palm short globular, densely granulated, carpopropodial articulation oblique; dactylus with long and robust occlusal protuberance.
Etymology
“robustus” referring to its robust constitution.
Other material examined
About 57 near-complete carapaces (MGSB 75447), 36 additional incomplete carapaces in MPZ (MPZ 2024/83), and one specimen figured in Ferratges, Reference Ferratges2017 (p. 52–53, fig. 27-B, pl. 13 B, C); there are about 10 isolated chelipeds in MGSB.
Remarks
The type species Xanthilites bowerbanki differs from the new species in several features. It has a wider frontal margin with larger indentations, strongly downturned, and features four blunt nodes. In X. bowerbanki, the frontal margin projects farther beyond the orbits, with four spinous processes visible in dorsal view and a V-shaped axial notch. In contrast, X. robustus n. sp. has orbits that are less rimmed and raised. The anterolateral margins bear two blunt nodes, separated by a vertical portion. In X. bowerbanki, these margins present two arched lobes and two more projecting, spinous processes.
The dorsal regions are gently swollen, moderately marked, and less subdivided in portions in Xanthilites robustus n. sp., whereas they are more swollen, strongly marked, and subdivided in portions in X. bowerbanki. The meso-, proto-, and epigastric regions are more tumid in X. bowerbanki, and the mesogastric region is smaller, more inflated, and bounded posteriorly by a deep groove. The urogastric region is just a depression behind the mesogastric region in the new species, whereas it is swollen and subtrapezoidal in shape in X, bowerbanki. The hepatic region is scarcely defined in the new species, while it is larger and more swollen in X. bowerbanki. The dorsal grooves are also more evident, deeper in X. bowerbanki, and weakly defined in the new species. The sternum also shows some notable differences: sternites 3–4 are swollen and elongated in the new species, but they are flatter and more defined by a deep oblique and longitudinal medial depression, described as a Y-shaped groove by Schweitzer (Reference Schweitzer2005) in X. bowerbanki. The epistome bears three arched indentations in the lower margin in X. bowerbanki, whereas it is robust and subrectangular in X. robustus n. sp. The chelae are short, globular, stout, and densely granulated in the new species, whereas they are more elongated and less ornamented in X. bowerbanki; the fingers are short and robust, with a strongly elongate occlusal protuberance in the dactylus, and only one low, robust protuberance in the occlusal margin of the fixed finger in X. robustus n. sp., whereas they are thinner and more elongated, with more numerous and less robust occlusal protuberances in X. bowerbanki (Bell, Reference Bell1858; Schweitzer, Reference Schweitzer2005).
Superfamily Goneplacoidea MacLeay, Reference MacLeay1838
Family Euryplacidae Stimpson, Reference Stimpson1871
Genus Alponella Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a
Type species
Alponella paleogenica Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a, by original designation.
Fossil species included
Alponella paleogenica Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a; Alponella sp.
Alponella sp.
(1–3) Eohexapus simplex n. sp., holotype (MGSB 77607) in dorsal (1), frontal (2), and left lateral (3) views. (4) Alponella sp. in dorsal view (MPZ 2024/85). (5–8) Aragolambrus collinsi Ferratges, Zamora, and Aurell, Reference Ferratges, Zamora and Aurell2019, (MPZ 2024/86) detail of frontal ventral view (5) with epistoma and antennular pits; (6) dorsal view of MGSB 75458; ventral view (7) and (8) detail of the pterigostomial region with the ridge of tubercles (MGSB 75459). (9–14) Galenopsis ossoi n. sp. (9–12) MGSB 75439 in ventral (9), dorsal (10), and frontal views without and with chelipeds (11, 12 respectively); frontal (13) and dorsal (14) views of the paratype MGSB 75440. (15–18) Parhalimede antiqua n. sp. holotype (MGSB 75465) in dorsal view (15), and paratype MPZ 2024/87 in frontal (16), right lateral (17), and dorsal views (18).
Description
Carapace subhexagonal to subcircular, slightly wider than long, longitudinally convex. Front broad, protruding, downturned, with median groove; frontal margin almost straight. Orbits wide, slightly raised, with orbital margin entire. Anterolateral margins short, convex, not well preserved; posterolateral margins longer, convex. Dorsal regions scarcely defined.
Material examined
One incomplete specimen, MPZ 2024/85.
Remarks
The specimen is included in the genus Alponella because of its subhexagonal carapace, slightly wider than long; shape of the frontal margin; and the rounded shape and oblique position of the orbits. The only other species is A. paleogenica Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a, from the early Eocene of Italy, but Alponella sp. can be differentiated by its less marked dorsal regions and a less elongated outline of the carapace; the front is flat, without inflations; and the orbits are only weakly rimmed. For contrast, the Italian species presents a frontal margin with two strongly swollen lobes, the orbits are notably rimmed, and the dorsal regions are more evident, with gentle inflations and weak grooves (Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a). With only one incomplete carapace, we assign this taxon to the genus Alponella, keeping it in open nomenclature.
Superfamily Hexapodoidea Miers, Reference Miers1886
Family Hexapodidae Miers, Reference Miers1886
Genus Eohexapus De Angeli, Guinot, and Garassino, Reference De Angeli, Guinot and Garassino2010
Type species
Eohexapus albertii De Angeli, Guinot, and Garassino, Reference De Angeli, Guinot and Garassino2010, by original designation.
Fossil species included
Eohexapus albertii De Angeli, Guinot, and Garassino, Reference De Angeli, Guinot and Garassino2010; E. simplex n. sp.
Eohexapus simplex new species
Type material
Only one complete carapace, the holotype MGSB 77607.
Diagnosis
Carapace subrectangular, frontal margin downturned, nearly straight. Orbits small, directed forward. Anterolateral margins short, broadly arched, bearing numerous granules. Posterolateral margins subparallel, slightly convergent backwards. Posterior margin long, slightly convex. Lateral sides of carapace vertical, bearing numerous granules. Dorsal regions of carapace poorly defined.
Description
Carapace wider than long, subrectangular; dorsal surface convex longitudinally, smooth, without deep cervical and branchiocardiac grooves; arched, short, branchio-cardiac depressions; mesogastric and cardiac regions poorly defined by shallow grooves. Surface ornamented by spaced pits, anterior margins of carapace and lateral sides with dense granulation. Front depressed, narrow, downturned, extending beyond orbits, widened distally, sulcate; margin straight in frontal view. Orbits reduced and rounded; supraorbital border rounded, weakly rimmed; upper orbital margin sinuous; anterolateral margin convex, ornamented with small granules; posterolateral margins subparallel, somewhat convergent backwards, posterior portion with rimmed, large, concavity; wide posterior margin, slightly convex. Lateral margins convex, vertical; posterior portion with large concavity for the insertion of last pereiopods.
Etymology
“simplex”, due to the simplicity of its carapace.
Remarks
Despite the complete preservation of dorsal characters, including the fronto-orbital construction, in absence of ventral characters and chelipeds, or more numerous specimens, we include this new taxon in the genus Eohexapus. Both E. simplex n. sp. and the Italian taxon E. albertii, share a subrectangular outline of carapace; with short, broadly arched anterolateral margins, bearing granules; slightly arched and somewhat convergent posterolateral margins; and a long weakly convex posterior margin. The new taxon presents a more subquadrate outline of the carapace; a nearly straight frontal margin; anterolateral margin and the lateral sides are densely covered by notable granules; and short, arched, well-marked branchiocardiac grooves. For contrast in the Italian species, the outline is more subrectangular, being notably wider; the frontal margin is bilobed from dorsal view, with both lobes slightly swollen; in frontal view the margin exhibits a thin rim; the anterior portion of lateral margins is visibly rimmed; the granulation over the dorsal carapace and vertical sides is smaller and differently distributed; the dorsal surface exhibits two big, rounded depressions close to the cardiac region. The fossil species Stevea cesarii Beschin et al., Reference Beschin, Busulini, De Angeli and Tessier1994, is very similar, but shows a different outline of the carapace, subtrapezoidal instead of subrectangular, with the lateral margins divergent backwards; the orbits are strongly rimmed; the posterior margin is more convex and presents a notable rim. Other fossil genera assigned to the Hexapodidae exhibit still more notable differences (see De Angeli, Guinot, and Garassino, Reference De Angeli, Guinot and Garassino2010).
Superfamily Parthenopoidea MacLeay, Reference MacLeay1838
Family Parthenopidae MacLeay, Reference MacLeay1838
Subfamily Dairoidinae Števčić, Reference Števčić2005
Genus Aragolambrus Ferratges, Zamora, and Aurell, Reference Ferratges, Zamora and Aurell2019
Type species
Aragolambrus collinsi Ferratges, Zamora, and Aurell, Reference Ferratges, Zamora and Aurell2019, by original designation.
Aragolambrus collinsi Ferratges, Zamora, and Aurell, Reference Ferratges, Zamora and Aurell2019
Reinterpreted and idealized reconstruction of Aragolambrus collinsi Ferratges, Zamora, and Aurell, Reference Ferratges, Zamora and Aurell2019, based on the new material.
Reference Ferratges, Zamora and Aurell2019 Aragolambrus collinsi Ferratges, Zamora, and Aurell, fig. 4.
Reference Ferratges, Zamora and Aurell2021a Aragolambrus collinsi; Ferratges et al., p. 11, fig 7 M.
Holotype
An almost complete carapace preserving chelipeds (MPZ-2019/210).
Emended diagnosis
Carapace subtriangular to pentagonal, longer than wide; orbits inflated; regions inflated; epibranchial margin slightly expanded. Projected frontal margin, triangular, with interorbital depression. Exorbital angle acute. Anterolateral margins almost straight; gastro-orbital notch present. Hepatic margin distinct with small spine, not continuous with epibranchial region. Hepatobranchial notch present, distinct. Epibranchial margin convex, angled at last epibranchial spine; posterolateral margin converging backward. Dorsal surface densely tuberculated with non-coalescent mushroom-shaped tubercles. Proto-, meso-, and metagastric regions differentiated, without ridge; protogastric region is most developed. Hepatic region inflated, slightly lower than epibranchial, gastric regions. Epibranchial region without continuous diagonal ridge. Epistome densely ornated. Pterygostomial ridge present. Subepibranchial region narrow, tuberculate. Epimeral line bordered by numerous small tubercles. Cheliped manus outer margin with 3–5 teeth, triangular in shape and widely spaced; inner margin composed by only three ornamented tubercles; outer side covered with tubercles of variable size (diagnosis modified from Ferratges et al., Reference Ferratges, Zamora and Aurell2019).
Material examined
Five specimens in MGSB. Two of them represent complete carapaces (MGSB 75458; MGSB MGSB 75459; and some remains (MPZ 2024/86), and MGSB 77610a–c.
Remarks
The new material studied allows further characters to be included in the original diagnosis proposed by Ferratges et al. (Reference Ferratges, Zamora and Aurell2019); especially those from the ventral view of the carapace. In addition, the new data observed in the new material was used in Ferratges et al. (Reference Ferratges, Luque, Domínguez, Ossó, Aurell and Zamora2023b) to clarify the systematic position of Phrynolambrus Bittner, Reference Bittner1893. The obtained results suggest a close position of both genera that are included in the subfamily Dairoidinae Števčić, Reference Števčić2005.
Superfamily Pilumnoidea Samouelle, Reference Samouelle1819
Familia Galenidae Alcock, Reference Alcock1898
Subfamily Halimedinae Alcock, Reference Alcock1898
Genus Parhalimede Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b
Type species
Parhalimede ornata Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b by original designation.
Fossil species included
Parhalimede antiqua n. sp., P. ornata Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b.
Parhalimede antiqua new species
Type material
Eleven specimens, the holotype MGSB 75465, and 10 paratypes MGSB 75466a–c, MGSB 75467a–c, MPZ 2021/41, MPZ 2024/87, MPZ 2024/88, MPZ 2024/89.
Diagnosis
Carapace subhexagonal, strongly convex, wider than long; frontal margin sulcate medially, with two rows of granulated ridges; small, rimmed, anterolaterally directed orbits; short and acute outer-orbital spine; convex anterolateral margins, with four granulated blunt nodes, last one spinous; posterolateral margin longer, slightly convex, without spines; posterior margin straight, finely rimmed, corners slightly rounded. Dorsal regions subdivided in portions, raised, swollen, tip of regions densely granulated.
Description
Carapace subhexagonal in outline, strongly convex in longitudinal and transverse sections; wider than long, maximum width at level of last anterolateral spine, L/W ratio about 0.81. Frontal margin nearly straight, slightly sulcate medially; with two rows of parallel granules and two small medial lobes when seen from frontal view. Orbits small, somewhat raised and rimmed, bearing two barely perceptible supraorbital fissures; short and acute outer-orbital spine. Fronto-orbital margin occupying about 62% of carapace width. Anterolateral margins slightly arched, convex, with four blunt, stout nodes covered by granules, the last one sometimes more spinous and protruding; posterolateral margin longer, nearly straight, only slightly convex, without spines. Posterior margin nearly straight, only somewhat convex, finely rimmed, corners slightly rounded. Dorsal regions well defined, divided into numerous portions, large, strongly raised, swollen, bearing numerous big granules. Epibranchial regions subcircular, situated close to the frontal margin; epigastric regions with a medial longitudinal groove; mesogastric region relatively small, transversely subelliptical in shape, with narrow, long, anterior extension. Hepatic region large, strongly swollen, obliquely positioned. Urogastric region defined by a horizontal ridge of granules. Epibranchial region divided into three portions; postbranchial regions defined by a large swelling. Cardiac region broad, subpentagonal, with five rounded swellings. Intestinal region flattened, barely distinct from cardiac lobe. Dorsal grooves numerous, defined as narrow and shallow depressions.
Etymology
“antiqua” referring to the fact that it is the oldest representative of the genus.
Remarks
The new taxon has important similarities with Parhalimede ornata Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b, from the early Lutetian of Italy, such as the general outline, similar fronto-orbital construction, rather similar anterolateral margins, and the shape and distribution of dorsal regions. Nevertheless, the new species exhibits a more subhexagonal outline of the carapace, strongly convex in both directions; the front is straighter and only slightly sulcate; the orbits bear nearly imperceptible incisions; the anterolateral margins bear only four stout, blunt nodes, covered with granules, in some remains the fourth node is somewhat more spinous but few protruding; the posterolateral margins are clearly straight and devoid of granules, tubercles, or spines; the posterior margin is finely rimmed; the dorsal regions are larger, more raised, and swollen, with narrower depressions between them.
Family Pilumnidae Samouelle, Reference Samouelle1819
Genus Galenopsis Milne-Edwards, Reference Milne-Edwards1865
Type species
Galenopsis typica Milne-Edwards, Reference Milne-Edwards1865, by original designation.
Fossil species included
Galenopsis crassifrons Milne-Edwards, Reference Milne-Edwards1865, G. depressa (Milne-Edwards, Reference Milne-Edwards1872), G. murchisoni Milne-Edwards, Reference Milne-Edwards1865, G. ossoi n. sp.; G. pustulosa (Milne-Edwards, Reference Milne-Edwards1865), G. ristorii Checchia-Rispoli, Reference Checchia-Rispoli1905, G. schopeni Checchia-Rispoli, Reference Checchia-Rispoli1905, and G. similis Bittner, Reference Bittner1875.
Galenopsis ossoi new species
Type material
Three specimens, the holotype is MGSB 75439 (measurements: W, 49 mm, L, 28 mm) and the paratypes are 75440a, b.
Diagnosis
Carapace subtrapezoidal, wider than long; frontal margin downturned, rimmed, with relatively deep posterior groove; orbits subcircular, strongly rimmed; anterolateral margins rimmed, with single arched lobe and two blunt nodes; posterolateral margins straight; posterior margin notably concave. Cheliped surface smooth, heterochelous, with the right bigger; occlusal margins of right cheliped with blunt molariform teeth; fingers of left cheliped thin, elongated, without occlusal teeth.
Description
Carapace subtrapezoidal in shape, wider than long, widest at position of the last anterolateral node, L/W ratio about 0.67; convex longitudinally, less convex transversely. Front strongly downturned, nearly straight, slightly sulcate medially, rimmed, with a deep posterior groove when seen from dorsal view; broad, with two notable arched lobes bounded laterally by thin, acute spines when seen from frontal view. Orbits small weakly arched from dorsal view, outer-orbital corner with spinous appearance; orbits subcircular, closed, from frontal view; supraorbital margins entire, strongly rimmed; fronto-orbital width occupying about 45% of maximum carapace width. Anterolateral margin short, arched, strongly rimmed, with three lobes, first of which immediately behind orbit, gently arched; the two posterior lobes are stout, robust, blunt nodes. Posterolateral margins longer than anterolateral, nearly straight converging backwards. Posterior margin wide, concave, with a thin rim. Dorsal regions not well differentiated; epigastric region small, with strong swellings directed forwards. Only weak, arched, branchiocardiac grooves are defined in some specimens. Dorsal surface smooth. Chelipeds smooth, without ornamentation; strongly marked heterochely. Large right chela, palm robust, globular oval in cross section. Robust fingers, with blunt molariform teeth. Left chela smaller, more elongate; fingers elongated, thin, without strong denticles. Buccal frame subhexagonal; endostome large, stout, bearing a longitudinal groove; exostome elongate. Sternum wide, subtriangular, with long base. Sternites 1–2 subtriangular, fused, with thin and elongate apex; sternites 3–4 fused, with large episternite 4; sternite 5 horizontal, with rounded lateral corner; sternites 6–7 narrow, obliquely situated.
Etymology
Honoring Àlex Ossó, a prolific author on decapod systematics.
Remarks
The new taxon shares the main characters assigned to the genus Galenopsis, such as the carapace expanded laterally, wider than long; orbits small; anterior part bowed, but the front edge rises so as to form a rather thick, beaded rim that continues to the anterolateral margins; anterolateral margins slightly trilobate and shorter than posterolateral ones; and posterolateral margins almost straight; dorsal regions poorly marked (see Milne-Edwards, 1875). Galenopsis depressa has a concave posterior margin that is straight in the new species (see Beschin et al., Reference Beschin, Busulini, Fornaciari, Papazzoni and Tessier2018). In addition, Galenopsis ossoi n. sp. presents on the anterolateral margin a first arched lobe, a second rather protruding node and a posterior stout but blunt node, whereas G. depressa exhibits the two first lobes as gently arched, and the posterior node spinous, strongly protruding. The posterolateral margins are more straight in the new species, less convergent posteriorly, with a less marked lateral angle. The new taxon has a more elongated outline than G. crassifrons, and a smooth dorsal surface, not covered with small pits. Other differences are illustrated in Ferratges et al. (Reference Ferratges, Zamora and Aurell2020) in which the anterolateral nodes are defined by two gently arched lobes and a posterior protruding, spinous, node. It is also easily distinguishable from G. similis because it has a less prominent frontal margin, a more oval outline, and orbits oriented forwards.
Superfamily Majoidea Samouelle, Reference Samouelle1819
Family Majidae Samouelle, Reference Samouelle1819
Subfamily ?Majinae Samouelle, Reference Samouelle1819
Genus Spinirostrimaia Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2012
Type species
Micromaia margaritata Fabiani, Reference Fabiani1910, by original designation.
Fossil species included
Spinirostrimaia margaritata (Fabiani, Reference Fabiani1910); S. echinata Ferratges et al., Reference Ferratges, Domínguez, Ossó and Zamora2023a.
?Spinirostrimaia sp.
(1–3) Lovaroides sp. MGSB 77613a in dorsal (1), frontal (2), and right lateral (3) views. (4–7) Liocarcinus tridentatus n. sp. holotype (MGSB 75448) in dorsal (4), lateral (5), and oblique frontal (6) views; (7) paratype MGSB 75449 in dorsal view. (8–10) Microboschettia elegans n. gen. n. sp. holotype (MGSB 77609) in frontal (8), dorsal (9), and lateral (10) views. ?Spinirostrimaia sp. (11) in dorsal view (MGSB 88654).
Description
Carapace pyriform (not totally preserved). Lateral margins convex, notched by the cervical groove. Dorsal regions ornamented with pearl-shaped tubercles (probably broken spines); carapace regions well defined by relatively shallow grooves; axial regions elevated above other regions. Proto- and mesogastric regions inflated; meta- and urogastric regions narrower than mesogastric and cardiac regions; hepatic region inflated; branchial regions wide; epi- and mesobranchial regions inflated, poorly differentiated by a shallow groove; metabranchial region slightly depressed; cardiac region inflated; branchiocardiac grooves deep. Posterior margin not preserved.
Material examined
One incomplete specimen (MGSB 88654).
Remarks
The studied material cannot be assigned on the species level because the specimen lacks important diagnostic elements such as orbits and pseudorostrum. However, the specimen can be assigned questionably to Spinirostrimaia based on the elongate carapace general outline, and distribution of dorsal regions (see diagnosis in Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2012) with a similar morphology in the preserved dorsal regions (gastric, hepatic, branchial, and cardiac regions).
Superfamily Portunoidea Rafinesque, Reference Rafinesque1815
Family Carcinidae MacLeay, Reference MacLeay1838
Subfamily Polybiinae Paul’son, Reference Paul’son1875
Genus Microboschettia new genus
Type species
Microboschettia elegans n. gen. n. sp. by monotypy.
Diagnosis
As for the type species by monotypy.
Etymology
The generic name refers to the small size, together with Boschettia, the most similar genus.
Remarks
The fossil genus Boschettia Busulini et al., Reference Busulini, Tessier, Beschin and De Angeli2003, shows similarities with the new genus in the general shape of the carapace, frontal margin, orbits, and dorsal ornamentation. However, Boschettia presents a shorter frontal margin, broader orbits, strongly granulated dorsal surface and a very long fourth anterolateral spine, all of which precludes a congeneric relationship with Microboschettia n. gen (see Busulini et al., Reference Busulini, Tessier, Beschin and De Angeli2003, pl. 4, fig. 2).
Microboschettia elegans new species
Type material
Two specimens; the holotype MGSB 77609, the paratype MGSB 77614.
Diagnosis
Carapace subquadrate, nearly wider than long; frontal margin with four lobes, projecting beyond orbits; orbits large, with two notches, well-developed suborbital spine, visible from dorsal view; anterolateral margin short, with two spines, last largest, outwardly directed; posterolateral margin convex, with small spine just behind last anterolateral spine. Dorsal regions well defined by swellings and spinous tubercles on tip of gastric, cardiac, and branchial regions. Cardiac region largest, strongly swollen, bearing protruding tip. Dorsal grooves defined by shallow depressions. Lateral portion of cervical groove horizontal. Dorsal regions densely covered by noticeable granules.
Description
Carapace subquadrate, moderately vaulted; nearly as wide as long, maximum width at level of last anterolateral spine, L/W ratio about 0.9. Frontal margin broad, slightly projecting beyond orbits, not completely preserved, with four spines, occupying about 25% of the total width of carapace. Orbits large, broad, with two differentiated portions; supraorbital margin divided into three lobes by two supraorbital fissures; the two inner-orbital lobes are small, slightly spinous, the intra-orbital lobe is nearly straight, the outer-orbital tooth large, stout, subtriangular; suborbital tooth extremely developed, subtriangular, first portion of the supraorbital margin finely rimmed, bearing two small lobes. Fronto-orbital margin about 0.8 of carapace width. Anterolateral margins slightly arched, shorter than the posterolateral margins, bearing two small conical spines, the posterior the largest, directed outwards. Posterolateral margins broadly convex, longer than the anterolateral, convergent posteriorly, bearing a small concavity in the lower corner, at position of the fifth pereiopod. Posterior margin not preserved. Mesogastric region well defined, large, swollen, subdivided in portions, bounded by shallow grooves, bearing eight pointed tubercles on tip of regions, mesogastric region the largest and more swollen, subpentagonal in shape, with a notably protruding tip; horizontal gastric slits are present in the lower portion of the mesogastric region; urogastric lobe transversely narrow, separated anteriorly by the cervical groove, which is horizontal in the lateral portion. Cardiac region large, subpentagonal in shape, strongly swollen, bearing a prominent tubercle on tip. Intestinal region flattened, barely distinct from cardiac lobe. Hepatic regions swollen, bearing a pointed tubercle, delimited from branchial regions by the cervical groove, delimited from gastric regions by the gastro-hepatic groove. Dorsal surface of carapace and the vertical lateral sides are densely and uniformly covered by notable granules of similar size.
Etymology
“elegans” referring to its elaborate appearance.
Remarks
Boschettia giampietroi Busulini et al., Reference Busulini, Tessier, Beschin and De Angeli2003, from the middle Eocene of Italy shows similarities with the new species in the general shape of the carapace, similar construction of fronto-orbital margin, orbits, similar distribution of dorsal regions, ornamentation and similar spines in the lateral margin (see Busulini et al., Reference Busulini, Tessier, Beschin and De Angeli2003, pl. 4, fig. 2). However, Microboschettia elegans n. gen. n. sp. is easily distinguishable in having a much more subquadrate carapace and smaller size; the frontal margin is somewhat broader; broader orbits, which exhibit a clearly differentiated supraorbital margin, with different shape and distribution of intraorbital projections; the outer orbital tooth is large, stout, and subtriangular; the anterolateral margins have less developed spines, with only two small, short, conical nodes. The posterior margin is not totally preserved in the new taxon.
Genus Lovaroides Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b
Type species
Lovaroides elegans Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b, by original designation.
Fossil species included
The type species is the only species included.
Lovaroides sp.
Description
Carapace subhexagonal, wider than long, L/W ratio about 0.75, maximum width at position of the last anterolateral tooth, vaulted in longitudinal and transverse sections. Frontal margin broad, nearly straight, with four small lobes, the two axial ones more protruding. Orbits large, anterolaterally directed, without apparent supraorbital fissures, outer orbital spine reduced. Small and oblique indentation between orbits and frontal margin. Fronto-orbital margin about 66% of the maximum width; anterolateral margin arched, short, bearing three subtriangular teeth, excluding the outer orbital. Posterolateral margin arched, bearing a small spine. Posterior margin not well preserved. Dorsal regions poorly defined. Gastric regions broad, large, only gently swollen, similarly swollen posterior portion of the branchial region and cardiac region. Cervical and branchiocardiac grooves shallow, weakly defined. Dorsal surface of carapace smooth.
Material examined
Two incomplete carapaces, MGSB 77613a, b.
Remarks
The new material shows several similarities with the type species, Lovaroides elegans, in the outline of the carapace, frontal margin with four small lobes, the two medial somewhat more developed; orbits broad, entire, without supraorbital fissures; anterior margins with similar teeth; and dorsal regions of carapace weakly defined. However, the two species present notable differences: the new material exhibits a straighter frontal margin, with the two axial lobes more prominent; the anterolateral margin bears three flattened, triangular spines; the carapace presents a subhexagonal outline, being wider than the type species; the gastric, mesobranchial, and cardiac regions are scarcely inflated; and the dorsal grooves are weakly defined. The Italian species, L. elegans, presents a much more subcircular outline of the carapace; the frontal margin is more sinuous, with smaller axial lobes; the lateral nodes are spinous, conical, and not contiguous, with space between them; the gastric, epibranchial and cardiac regions are well defined, swollen; and the dorsal grooves are shallow but better defined (Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b). The similarities and distinctions with other genera were discussed in Beschin et al. (Reference Beschin, De Angeli, Checchi and Zarantonello2016b). Prealpiplax lessinea Beschin, Bussulini, and Tessier, 2016, and Corallioplax exigua Beschin, Busulini, and Tessier, 2016, have similar anterolateral margins, with the same number of teeth, the penultimate the largest, and a similar carapace outline. However, they show a different morphology and distribution of dorsal regions, anterolateral spines more pointed, and a clearly different frontal margin wider, straighter and less prominent (see Beschin et al., Reference Beschin, Busulini, Tessier and Zorzin2016a, p. 144–146., pl. 19).
Genus Liocarcinus Stimpson, Reference Stimpson1871
Type species
Portunus holsatus Fabricius, Reference Fabricius1798, by original designation.
Fossil species included
Liocarcinus corrugatus (Pennant, Reference Pennant1777) also extant; L. depurator (Linnaeus, Reference Linnaeus1758) also extant; L. holsatus (Fabricius, Reference Fabricius1798) also extant; L. kuehni (Bachmayer, Reference Bachmayer1953); L. marmoreus (Leach, Reference Leach1816) also extant; L. oligocenicus (Paucă, Reference Paucă1929); L. oroszyi (Bachmayer, Reference Bachmayer1953); L. praearcuatus Müller, Reference Müller1996; L. pusillus (Leach, Reference Leach1816) also extant; L. rakosensis (Lőrenthey in Lőrenthey and Beurlen, Reference Lőrenthey and Beurlen1929); L. priscus Beschin et al., Reference Beschin, De Angeli, Checchi and Zarantonello2016b.
Liocarcinus tridentatus new species
Type material
Two almost complete carapaces in MGSB; holotype MGSB 75448; paratype MGSB 75449.
Diagnosis
Carapace subhexagonal, wider than long, maximum width at level of last anterolateral spine, about half of carapace length. Frontal margin advanced, large, broadly arched. Orbits wide; supraorbital margin without notches or fissures. Anterolateral margins arched, armed with three subtriangular teeth. Posterolateral margin longer, concave. Posterior margins straight. Dorsal regions defined by shallow grooves. Anterior extension of mesogastric process well marked, spatula-shaped, bounded by deep groove. Epibranchial swelling well marked, arched.
Description
Carapace subhexagonal in outline, moderately vaulted; wider than long, maximum width at level of last anterolateral spine, L/W ratio about 0.77. Frontal margin large, slightly advanced, broadly arched, entire. Orbits broad, without supraorbital fissures, anterolaterally directed, outer orbital teeth robust, subtriangular. Fronto-orbital margin occupying about 64% of maximum carapace width. Anterolateral margins arched, shorter than the posterolateral margins, armed with three robust subtriangular teeth, forwardly directed. Posterolateral margins slightly concave, elongated, convergent posteriorly. Posterior margin straight, finely rimmed. Dorsal regions well defined, gently swollen, bounded by shallow grooves. Mesogastric region transversely subelliptical; anterior extension of the mesogastric region elongated, spatula-shaped, with straight tip, bounded by a deep groove. Protogastric regions large, swollen. Epigastric regions subcircular, connected with the protogastric region. Urogastric region arched. Hepatic region slightly swollen, elongated, delimited from branchial regions by the cervical groove, delimited from gastric regions by the gastro-hepatic groove. Epibranchial ridge well marked, arched, reaching the last anterolateral tooth; meso- and metabranchial regions inflated, large. Cardiac region broad, subpentagonal. Intestinal region flattened, barely distinct from cardiac lobe. Dorsal surface of carapace smooth, without ornamentation.
Etymology
“tridentatus”, referring to the three teeth in the anterolateral margins.
Remarks
Liocarcinus tridentatus n. sp. has a frontal margin entirely arched, like in fossil species L. priscus and the modern L. navigator (Herbst, 1794). However, the new taxon is clearly distinct in having a much broader and advanced frontal margin; complete orbits, without supraorbital fissures; anterolateral margins with only three teeth; different posterolateral margins, without the large concavity for the insertion of the last pereiopods, the anterior extension of the mesogastric process spatula-shaped, bounded by deep grooves. Liocarcinus priscus exhibits a less broad and advanced frontal margin; orbits with two supraorbital fissures; anterolateral margins with four teeth, excluding the outer orbital; posterolateral margins with a strong concavity in the lower corner for the insertion of the last pereiopods; anterior mesogastric process narrow and pointed.
Indeterminate and isolated chelipeds
Isolated chelipeds from the studied outcrop. (1–5) Indeterminate chelipeds. (6–8) isolated manus of ?Rhinolambrus sp. in outer side (6), inner side (7), and frontal (8) views (MGSB 77606). (9–12) Paromola sp. in inner (9, 10), outer (11), and frontal (12) views; (9) MPZ 2024/90, (10, 12) MGSB 75468.
Remarks
In addition to the great diversity of decapod crustaceans found, a large number of isolated chelae have been observed. Some of them can be assigned to brachyuran taxa such as Aragolambrus collinsi Ferratges, Zamora, and Aurell, Reference Ferratges, Zamora and Aurell2019; Pyrenicola pyrenaica (Artal and Vía, Reference Artal and Vía1989) (see Artal and Ossó, Reference Artal and Ossó2024); Eocarpilius ortegai Artal and van Bakel, Reference Artal and van Bakel2018b; Oscacarpilius rotundus Artal and van Bakel, Reference Artal and van Bakel2018b; Ilerdapatiscus guardiae Artal and van Bakel, Reference Artal and van Bakel2018a; Locomius parthenopimimus n. gen. n. sp.; Xanthilites robustus n. sp.; and various Dromioidea such as: Mclaynotopus longispinosus Artal et al., Reference Artal, Ferratges, van Bakel and Zamora2022; and Kromtitis isabenensis Artal et al., Reference Artal, Ferratges, van Bakel and Zamora2022 (see Artal et al., Reference Artal, Ferratges, van Bakel and Zamora2022).
However, some of the isolated chelae cannot be included in any known species (Fig. 9). For example, some elongated specimens (MGSB 75468) resemble the material described by Ferratges et al. (Reference Ferratges, Domínguez and Ossó2021b) from the Roda Formation, assigned to the genus Paromola Wood-Mason in Wood-Mason and Alcock, Reference Wood-Mason and Alcock1891, collected four kilometers from the studied outcrop in the present work (Fig. 9.9–9.11). One isolated right propodus (MGSB 77606) is tentatively assigned to the genus ?Rhinolambrus Milne-Edwards, 1878 (Parthenopinae) due to its elongated morphology, with tubercles distributed in three rows, situated in the lower, upper, and inner margins, and its slightly triangular section. The mentioned characters are typical in Parthenopinae as described and illustrated by different authors (i.e., Tan and Ng, Reference Tan and Ng2007, and references herein), and show similarities with modern species of the genus Rhinolambrus.
Final remarks
The remarkable site of Ramals has provided a great diversity of decapod crustaceans (see Table 1). In addition, its exceptional exposure and state of preservation of fossils allowed controlled sampling, which has made it possible to interpret the distribution of these species within the same environment (Ferratges et al., Reference Ferratges, Zamora and Aurell2021a). This sole outcrop concentrates the greatest diversity of associated decapod crustaceans for the Eocene of the Iberian Peninsula and is one of the most diverse worldwide locations for this period, having 44 different species (including the taxa described here) to date, in addition to some remains that could not be assigned to any of the described taxa.
Considering the quantitative data presented by Ferratges et al. (Reference Ferratges, Zamora and Aurell2021a), decapod crustaceans were common components in these early Eocene reef assemblages. The most important contribution of this site is that some of the taxa represent the oldest records in some genera of modern families (Cancridae; Carpiliidae; Parthenopidae). These records have important implications for molecular clock calibrations (Luque et al., Reference Luque, Bracken-Grissom, Ortega-Hernández and Wolfe2023) and the understanding of modern hot spots of decapod crustaceans.
Acknowledgments
This work has been supported by the projects CGL2017-85038-P subsidized by the Spanish Ministry of Science and Innovation, the European Regional Development Fund, and Project E18-20R Aragosaurus: Recursos Geológicos y Paleoambientes of the government of Aragón-FEDER. The research of F.A. Ferratges was funded by a FPU Grant (FPU17/03623) of Spanish Ministry of Science and Innovation and Programa Juan de la Cierva (ref. JDC2022-049170-I), financed by MCIU/AEI/10.13039/501100011033 and for the European Union NextGenerationEU/PRTR, the project CGL2017-85038-P, subsidized by the Spanish Ministry of Science and Innovation; I. Pérez provided photographic assistance. The staff of the MGSB allowed the study of their historical decapod collections. Thanks to A. Onetti (Barcelona, Spain) for material donated. We are also grateful to the reviewers C.E. Schweitzer (Kent State University), F.J. Vega (Universidad Nacional Autónoma de México), and an anonymous reviewer, who greatly improved the resulting manuscript.
Competing interests
The authors declare no competing interests.
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