Biodiversity is the number and variability of genes, species, and communities in space and time (Norse et al., 1986; Wilson, 1988; Heywood and Baste, 1995). The fundamental question that has governed its study in modern times is Hutchinson's (1959): “Why are there so many kinds of animals?” In more recent decades, a somber subquestion has been added: How many species are dying every year (e.g., Wilson, 1992)?

Stromatoporoids are found in the Dayville and Deansboro Members of the Coeymans Formation in central New York, where they are common to rare. The most common species present are Habrostroma centrotum (Girty) and H. microporum (Girty). Present in lesser numbers are Parallelostroma foveolatum (Girty), Atopostroma sp. 1, A. sp. 2, Coenostroma cf. C. monticuliferum (Winchell), Coenostroma sp., Habrostroma cf. H. centrotum (Girty), and Coenostelodictyon cf. C. krekovi (Yavorsky). Although previously reported from the Coeymans, Coenostelodictyon jewetti (Girty) was not found. Species identifications were based on traditional qualitative methods, supplemented by statistics. The assemblage bears affinities with Lochkovian faunas in Virginia and the Canadian Arctic.

The first-described articulated Silurian sponges from Spain and Portugal include a moderate assemblage of hexactinellids and a single monaxonid demosponge. The sponges were collected from a thin layer at the top of the Cyrtograptus lundgreni-Monograptus testis graptolite biozone, in a possible volcanic ash of latest Homerian (Wenlock) age. The sponges are from southeastern Portugal and southwestern Spain in the Ossa-Morena Zone of the Hesperian Massif. The hexactinellid collection includes several specimens of the new species, Protospongia iberica, and fragments of Diagoniella species and Gabelia(?) sp. Specimens of the latter two taxa are too small for species identification. Demosponges are represented by a single described specimen of a probably new genus and species preserved as a “wreath” of monaxon spicules. Dermal and gastral layers are of very fine spicules developed over the moderately coarse, aligned, principal body spicules.

Epistreptophyllum cornutiformis Gregory, 1900, is the name assigned to a Middle Jurassic population of scleractinian corals from Kachchh, western India. Measurements of ten variables from 84 specimens of this population have been statistically examined by means of univariate and multivariate analyses. A wide range of variation in corallum shape, septal perforation, lateral septal surface ornamentation, nature of the endotheca, and that of the columella is observed. The great majority of specimens are solitary. The wide range of gradational variation observed in this population corresponds to and includes the morphological characters described for various scleractinian genera such as Protethmos Gregory, Metethmos Gregory, Frechia Gregory, and Epistreptophyllum Milaschewitsch. The assignment of these genera to this later senior synonym genus is supported by the description of a well-preserved topotype from Nattheim. The ornamentation of the septa in Epistreptophyllum is detailed and distances it from typical pennular corals.

“Lingulepis’ malongensis Rong from the upper part of the Lower Cambrian Chiungchussu Formation of Yunnan is referred to Lingulellotreta Koneva; L. malongensis (=Lingulellotreta ergalievi Koneva) is redescribed on the basis of new material from the Lower Cambrian of south Kazakhstan. It is the earliest known taxon of the Lingulellotretidae, which is unique within the Linguloidea in having an elongate pedicle foramen and internal pedicle tube. The occurrence of Lingulellotreta malongensis in south China is considered usually to be of Atdabanian age, but brachiopod based correlation with south Kazakhstan suggests that a possible Botomian or younger age, for both the upper part of Chiungchussu Formation in Yunnan and the lowermost part of Shabakty Group in the Malyi Karatau Range, is equally plausible.

All previously known late Ordovician and Silurian trimerellides of Kazakhstan are reviewed and reillustrated, together with some recently discovered taxa, including the late Caradoc-Ashgill Palaeotrimerella medojevi new species from the Chu-Ili Range, the late middle Ashgill Gasconsia cf. worsleyi Hanken and Harper, and Silurian Dinobolus cf. hubeiensis Rong and Yang, both from Central Kazakhstan. Kazakhstanian terranes appear to contain the oldest-known trimerellide faunas from late Llandeilo to early Caradoc. The observed geographic distribution of Ordovician trimerellides may be explained as the result of two major migrations from the Kazakhstanian terranes: 1) during the early Caradoc, to Gondwana and North America; 2) during the late Caradoc, to Baltica and Angaria. All local trimerellide lineages in Kazakhstan became extinct just before the Hirnantian, and were replaced in the Llandovery by new forms, probably of Chinese origin.

The Namurian Tsingyuan Formation from Ningxia, China, is divided into three members. The remarkably well-preserved gastropods from the Tsingyuan Formation belong to three assemblages: the Angyomphalus longicostatus—Glabrocingulum tongxinensis assemblage from the Lower Member; an assemblage of some siliceous Bellerophon sp., and Naticopsis sp. from the Middle Member; and the Euphemites hindi—Turbonitella semisulcatus assemblage from the Upper Member. Based on the associated ammonoids and conodonts, these assemblages are considered equivalent to the Eumorphoceras, Homoceras2-Reticuloceras1 and Reticuloceras2 zones of West Europe respectively.

The new genus Herminespina comprises extinct South American species of “Thais”-like ocenebrine gastropods with prominent colabral folds and a labral spine. Geographic range extensions into Peru are reported for the late Pliocene H. mirabilis and the late Miocene to Pliocene H. philippii, both previously known only from Chile. A new early Pliocene species, H. saskiae, is described from the Sacaco Basin of southern Peru and compared with an early Miocene muricid from Peru and Chile, Acanthina katzi. Herminespina is one of several genera of Neogene muricids in western South America that bear labral spines.

A new species of carcineretid crab, Carcineretesplanetarius, is described from the Upper Cretaceous (lower Maastrichtian) Barton Creek Dolomite at Albion Island, Belize. The age is based on the stratigraphic range of associated nerineid gastropods and correlation with nannoplankton, benthic foraminifera, and the other known congeneric species of crab found in Jamaica. Confirmation of this age aids in constraining the timing of ejecta deposits of the Chicxulub impact found at the top of Barton Creek Dolomite exposed on Albion Island. Paleoenvironmental and paleoecological analyses suggest that these crabs were swimmers in lagoonal settings, capable of burrowing a few centimeters into the mud for protection.

New finds of the trilobites Cobboldites tichkaensis Geyer, 1988, Pseudocobboldia pulchra (Hupé, 1953), Protolenus (Protolenus) densigranulatus Geyer, 1990, Latoucheia (Latoucheia) tichkaensis Hupé, 1953, and Acanthomicmacca neltneri Hupé, 1953, from the basal Middle Cambrian near the peak of Tizi n'Tichka in the central High Atlas, Morocco, supplement the known morphology of these species; the trilobites Acanthomicmacca new species, Oreisator tichkaensis new genus and species, and “Parasolenopleura” sp. from that locality are new. Acanthomicmacca neltneri is the first species of the genus and family that is described and figured in detail in terms of morphologic plasticity and ontogeny; Oreisator tichkaensis is the first ptychopariacean trilobite formally described and based on material from Africa. Trilobites and other fossils from the locality suggest a strong affinity to other Mediterranean and to Avalonian faunas, which is well supported by helcionelloid and hyolith genera.

Shelly fossils from the basal Middle Cambrian, near the peak of Tizi n'Tichka in the central High Atlas, Morocco, include the new hyolithids Oboedalites peregrinus new species, Emarites decorissimus new genus and species, Patholites insolitus new genus and species, Rodentilites cricetus new genus and species, Slapylites afer new species, Tajinella mosei new genus and species, and Tizilites creber new genus and species. New orthothecid hyoliths are Gracilitheca destombesi new species, Contitheca chrosniaki new species, Sysoievia exilis new genus and species and an indeterminate species of Circotheca. The presence of Obeodalites, Slapylites, and Contitheca suggests a strong affinity to other Mediterranean and to Avalonian faunas. Their occurrence in Morocco extends their geographic ranges from Europe, and further reenforces their usefulness as indicators of Middle Cambrian age.

Calymenid trilobites are common components of diverse Silurian silicified faunas recovered from the Cape Phillips Formation of the Cape Phillips Basin, central Canadian Arctic Archipelago. Calymenids are represented in the Wenlock of the northern Laurentian region by only two genera, Diacalymene Kegel, 1927, and Arcticalymene new genus (type species A. viciousi new species). Calymenid diversity in any given fauna is never higher than two species, although these species may be numerically abundant. Arcticalymene became extinct during the Homerian, at which point calymenids disappeared forever from the northern Laurentian record.

Other new taxa are Arcticalymene cooki new species, A. jonesi new species, A. matlocki new species, and A. rotteni new species. Material representing at least two more species of the new genus is reported in open nomenclature. Diacalymene gabrielsi Siveter and Chatterton, 1996, is recorded from the Cape Phillips Basin.

Ontogenies of three trilobites from the Garden City Formation (Tremadocian to early Arenigian; equivalent to Ibexian) are described: Tesselacauda depressa (Pilekiidae), Rossaspis pliomeris (Protopliomeropsinae), and Protopliomerella contracta (Cybelopsinae).

Comparison of both larval and adult features of the described trilobites with those of cheirurids and encrinurids suggests that three lineages of the Cheirurina existed during the Early and Middle Ordovician. Members of the first lineage show the following hierarchical relationships; (Tesselacauda depressa (Cheirurinae (Acanthoparyphinae (two separate Sphaerexochinae groups)))). Within the second lineage, the following internested relationships of its members are recognized; (Protopliomeropsinae (“early” cybelines (“advanced” cybelines and Encrinurinae))). The Cybelopsinae constitute the third lineage that is considered as an immediate outgroup to the above two lineages. Pattern of nested distribution of synapomorphies within all these lineages reveals that the two pliomerid subfamilies (Protopliomeropsinae and Cybelopsinae) do not share a recent common ancestor, suggesting that the Pliomeridae is a paraphyletic group.

New aulacopleuroidean trilobites from the Lochkovian of Oklahoma include the otarionine Cyphaspis carrolli new species from the Haragan Formation, and the brachymetopid Cordania wessmani new species from the overlying Bois d'Arc Formation. Cyphaspis carrolli is the first record of the genus from the North American Devonian. It is a highly plesiomorphic species, dissimilar to contemporaries from Europe, but closely related to Silurian species from Northern Laurentia and England. Cordania wessmani had previously been interpreted as a possible sexual dimorph of Cordania falcata Whittington, 1960, but new material and information shows that the forms occur separately with no stratigraphic overlap. New information on trilobite occurrence in the Haragan and Bois d'Arc Formations does not support previous hypotheses of trilobite sexual dimorphism, but rather indicates the presence of distinct, stratigraphically successive faunas.

The taxonomy of the predominantly Australian fossil dipnoan genus, Neoceratodus, is revised and the Recent Australian lungfish, Neoceratodus forsteri, and two fossil species, Neoceratodus eyrensis and Neoceratodus nargun, are redefined. Two new species of the related Tertiary genus, Mioceratodus, are described on the basis of tooth plates from central and northern localities in Australia. These are Mioceratodus diaphorus and Mioceratodus poastrus. A new genus, Archaeoceratodus, is erected to include three rare Tertiary species and one Mesozoic species. The Tertiary members of this genus are the type species, Archaeoceratodus djelleh, described originally as Neoceratodus djelleh, and two new species, Archaeoceratodus rowleyi and Archaeoceratodus theganus. The Mesozoic species is Archaeoceratodus avus from Triassic and Cretaceous deposits in southeastern Australia, described originally as Ceratodus avus. All three genera belong in the family Neoceratodontidae.