Cercariae of two trematode species from the family Notocotylidae were found in the snails Radix auricularia and Boreoelona ussuriensis. Sexually mature flukes were obtained by experimentally infecting a duckling and a few chickens, respectively, with metacercariae from the found cercariae. Based on a combination of morphological and molecular (nuclear and mitochondrial markers) evidence, the trematodes grown in the duckling were identified as Notocotylus ikutai. The adult flukes obtained from the infected chickens were assigned to trematodes previously grouped into the genus Catatropis on the basis of morphological characteristics, including the structure of tegumental papillae. However, according to molecular data, the found trematodes were differentiated at the generic level from other Notocotylidae. Based on the above evidence, we here erect a genus, Neocatatropis n. g., to accommodate the type species Neocatatropis primorskii n. g. n. sp.

This study examines the interaction between regularity and complexity in the acquisition of morphology and morpho-syntax in Hebrew nominal inflection. Seventy-eight Hebrew-speaking children, ages 4–8, were tested, using sentence completion tasks, on nine structures from three linguistic systems: singular adjectival agreement, noun pluralization, and plural adjectival agreement. Regularity and complexity emerged as organizing factors across ages: regular structures precede irregular ones, and within each level of regularity, less complex structures were acquired before more complex ones. The findings are discussed within the Dual-Route Model pointing to the difference between rule-governed and memory-based knowledge, while suggesting that the advantage of regularity could be attributed to frequency as well as to the strength of regularity cues in language acquisition, as proposed by Usage-Based models. The advantage of less complex structures over more complex ones is accounted for by the greater cognitive and linguistic effort required to acquire the latter.

Hearts with a double-inlet and double-outlet right ventricle are infrequent. Due to their infrequency, it is unclear whether there are natural patterns in hearts like this. A systematic review was performed to identify published cases of double-inlet double-outlet right ventricle. Characteristics for individual reported hearts were collated and entered into a cluster analysis. Hearts with double-inlet, double-outlet right ventricles tended to fall into two clusters largely based on aortic atresia and systemic venous connections.

The case-number suffixes of the Western Nilotic language Nuer (Frank 1999) display a remarkable combination of formal simplicity and distributional complexity, which is manifested in: (i) a seemingly erratic form-function mapping that precludes attributing a consistent meaning to the suffixes, and (ii) a wealth of inflection classes only barely differentiated from each other. The suffixes looks as if they were rule-generated, but behave as if they were memorized. I advance a model of inflection combining principal parts, implicational rules, and default inheritance, in which the bulk of the complexity is attributed to the lexical stem, revealing the underlying systematicity behind suffix assignment.

Free association (e.g., what is the first word that comes to mind when given a cue word) can reveal multiple linguistic relationships between cues and responses, even when a specific association (i.e., semantic, phonological) is intended. In this study, we investigated the influence of morphological similarity on semantic and phonological free association. Previously collected large datasets were used to evaluate morphological similarity between cues and responses in a semantic association task and a phonological association task. The results indicate that morphologically related cue–response word pairs comprised less than 2% of pairs in both association tasks. When morphologically related responses were detected in both tasks, we found more words that were non-compounds than compounds, more decomposition than composition and more suffixation than prefixation. There were task-specific differences in the psycholinguistic properties of cue words eliciting morphologically related responses. We interpret the results following a two-stage lexical model, where free association primarily involves the exploration of conceptual/lemma representations in the mental lexicon, as opposed to form/lexeme representations.

While affix ordering often reflects general syntactic or semantic principles, it can also be arbitrary or variable. This article develops a theory of morpheme ordering based on local morphotactic restrictions encoded as weighted bigram constraints. I examine the formal properties of morphotactic systems, including arbitrariness, nontransitivity, context-sensitivity, analogy, and variation. Several variable systems are surveyed before turning to a detailed corpus study of a variable affix in Tagalog. Bigram morphotactics is shown to cover Tagalog and the typology, while other formalisms, such as alignment, precedence, and position classes, undergenerate. Moreover, learning simulations reveal that affix ordering under bigram morphotactics is subject to analogical pressures, providing a learning-theoretic motivation for the specific patterns of variation observed in Tagalog. I raise a different set of objections to rule-based approaches invoking affix movement. Finally, I demonstrate that bigram morphotactics is restrictive, being unable to generate unattested scenarios such as nonlocal contingency in ordering.

I present evidence from Navajo and English that weaker, gradient versions of morpheme-internal phonotactic constraints, such as the ban on geminate consonants in English, hold even across prosodic word boundaries. I argue that these lexical biases are the result of a maximum entropy phonotactic learning algorithm that maximizes the probability of the learning data, but that also contains a smoothing term that penalizes complex grammars. When this learner attempts to construct a grammar in which some constraints are blind to morphological structure, it underpredicts the frequency of compounds that violate a morpheme-internal phonotactic. I further show how, over time, this learning bias could plausibly lead to the lexical biases seen in Navajo and English.

A new species of spionid polychaete from the coastal waters of southwest India, Trochochaeta chakara sp. nov., is described and illustrated. Adults are common on Alappuzha mud banks (locally known as Chakara) off the coast of Kerala. They live in silty tubes in soft sediment and are characterized by the presence of two pairs of red eyes, caruncle extending to end of chaetiger 1, heavy falcate spines in neuropodia of chaetigers 2 and 3 (those in chaetiger 3 much stronger and darker), capillary chaetae in notopodia of chaetigers 1, 3–10, frayed heavy spines in neuropodia of chaetigers 4–13, hirsute capillaries in neuropodia from chaetiger 14, lateral interneuropodial membranes from chaetiger 14, one pair of ventral papillae on each chaetiger from chaetigers 14–16, bundles of acicular spines in notopodia from chaetigers 50–52, and small pygidium with up to six pairs of short cirri. This is the third species of Trochochaeta described and found in the Indian Ocean, including T. orissae (Fauvel, 1932) and T. cirrifera (Hartman, 1975).

The genus Strongyloides (Nematoda; Strongyloididae) comprises over 50 species of nematodes parasitic in terrestrial vertebrates, including humans (Homo sapiens), dogs (Canis lupus familiaris) and cats (Felis catus). Taxonomy of the genus has been shaped by over a century of morphological research, with the most widely adopted framework established in the late 1980s. Advances in molecular genetics have increasingly revealed cryptic diversity and yielded new insights into interspecific and intraspecific relationships within the genus. Despite the rapid expansion of molecular genetic data over the past decade, particularly for Strongyloides spp. infecting humans and companion animals, a synthesis of these findings remains lacking. Here, we review historical and contemporary literature on the taxonomy of Strongyloides spp. infecting humans (Strongyloides stercoralis, Strongyloides fuelleborni), dogs (S. stercoralis, including host-specific lineages and cryptic taxa) and cats (Strongyloides felis, Strongyloides planiceps, Strongyloides tumefaciens and S. stercoralis). We provide an updated overview of taxonomic histories, host ranges and key morphological features for genus identification and species differentiation, along with a synthesis of available molecular taxonomic data informed by phylogenetic and population genetic studies. This work is intended to serve as a renewed reference for researchers, diagnosticians and clinicians working with Strongyloides spp. in medical and veterinary contexts, supporting accurate diagnosis and guiding future taxonomic research on these nematodes.

The white mullet, Mugil curema (Mugilidae), is a catadromous euryhaline fish with an omnivorous diet, and is distributed mainly along the Pacific and Atlantic coasts of the Americas. Mullets represent an important economic resource for the artisanal fisheries in Mexico. In this study, 73 individuals of M. curema were analysed; specimens were sampled in 4 coastal lagoons of the Yucatán Peninsula, Mexico, between 2022 and 2024. Parasite identification was accomplished by using DNA sequences. Nineteen parasite taxa were found, including 1 monopisthocotylan, 1 copepod, 1 acanthocephalan, 1 nematode, and 15 trematodes. Specimens were sequenced for a nuclear or mitochondrial molecular marker. Ten taxa are reported for the first time in this host species, including the adult trematodes Saccocoelioides olmecae; Schikhobalotrema sp. 1 and sp. 2, Hemiuridae gen. sp., the larval trematodes Mesostephanus microbursa, M. cubaensis, Cardiocephaloides medioconiger, Saccularina sp., Bucephalus sp., as well as the larval nematode Contracaecum fagerholmi. Of the 21 metazoan parasites recorded, 58% were adults and 42% were larval stages. The checklist of the metazoan parasites of M. curema was updated. Our study contributes to the understanding of the parasite diversity of an economically important fish species with a wide distribution range and corroborates the usefulness of combining morphological and molecular data for species identification and for linking larval forms with adults to complete parasite life cycles. Our results will be useful in further studies of parasites as bioindicators of ecosystem health, and studies of the role of parasites in food webs in coastal lagoons.

The first report of Ophiophragmus luetkeni occurred in the British Virgin Islands; however, it was also recorded in Brazil, the United States Virgin Islands, and Trinidad and Tobago, yet its occurrence in Colombia was previously lacking. Between 2023 and 2024, four specimens were collected from sandy and muddy substrates in Cispatá Bay, Colombian Caribbean. Taxonomic identification was conducted through morphological observations and microstructural analysis using Scanning Electron Microscopy. A comparative table for Ophiophragmus species recorded in Colombia are also provided. This new record increases the number of Ophiophragmus species in Colombia to three, contributing to the country’s marine biodiversity and expanding the knowledge of O. luetkeni distribution.

The English past tense contains pockets of variation, where regular and irregular forms compete (e.g. learned/learnt, weaved/wove). Individuals vary considerably in the degree to which they prefer irregular forms. This article examines the degree to which individuals may converge on their regularization patterns and preferences. We report on a novel experimental methodology, using a cooperative game involving nonce verbs. Analysis of participants' postgame responses indicates that their behavior shifted in response to an automated co-player's preferences, on two dimensions. First, players regularize more after playing with peers with high regularization rates, and less after playing with peers with low regularization rates. Second, players' overall patterns of regularization are also affected by the particular distribution of (ir)regular forms produced by the peer.

We model the effects of the exposure on participants' morphological preferences, using both a rule-based model and an instance-based analogical model (Nosofsky 1988, Albright & Hayes 2003). Both models contribute separately and significantly to explaining participants' pre-exposure regularization processes. However, only the instance-based model captures the shift in preferences that arises after exposure to the peer. We argue that the results suggest an account of morphological convergence in which new word forms are stored in memory, and on-line generalizations are formed over these instances.