Ideas about morphological complexity have been used to classify languages and to link complexity to language age and social structure. Creoles and sign languages are often framed as younger and structurally simpler than other languages. Concurrently, sign language morphology has been described as paradoxical, as both simple and complex. This paper is a critical examination of claims about morphological complexity and its relationship to language age and social structure. We show that the theoretical and empirical foundations of claims that sign language morphology is paradoxical are flawed. Specifically, argumentation and evidence supporting analogies between creole and sign language complexity adopt theoretically contested and ideologically problematic assumptions about creoles and uncritically apply them to sign languages. We identify four flaws in argumentation: (i) use of limited morphological data to generate claims about global complexity, (ii) association of binary language categories with categorical complexity differences, (iii) use of language age to motivate predictions about morphological complexity, and (iv) extrapolating from creole complexity to sign language complexity. Based on these flaws, we develop nine theoretical and practical recommendations for working with morphological complexity and discuss uncritical cross-disciplinary transfer of ideas.

This study examined how word identification is influenced by interword spacing and morphological complexity in Thai, a script without interword spacing. While previous research supported the facilitative effect of interword spacing on Thai word identification, they did not account for the potential effects of the words’ morphological structure. The challenge of word identification becomes more pronounced when readers have to identify compound words (e.g., bathroom) when reading sentences without interword spacing. In an eye-tracking experiment that manipulated interword spacing (unspaced, spaced) and noun type (bimorphemic compound, monomorphemic) in Thai sentences, we confirmed previous findings that interword spacing has a facilitative effect on word identification, as evidenced by shorter first fixation duration, gaze duration and total fixation time. Furthermore, we observed an interaction effect indicating that interword spacing had a larger facilitative effect on the identification of compounds compared to monomorphemic words. Our results also revealed that the morphological structure of Thai words can influence saccadic movements, e.g., the first fixation landing position was closer to the beginning of compounds than to simple words. We suggest that the orthography-language interface, a language-specific feature, should be considered a major component in eye movement models of reading.

Non-native languages tend to be acquired through a combination of explicit and implicit learning, where implicit learning requires coordination of language information with referents in the environment. In this study, we examined how learners use both language input and environmental cues to acquire vocabulary and morphology in a novel language and how their language background influences this process. We trained 105 adults with native languages (L1s) varying in morphological richness (English, German, Mandarin) on an artificial language comprising nouns and verbs with morphological features (number, tense, and subject-verb [SV] agreement) appearing alongside referential visual scenes. Participants were able to learn both word stems and morphological features from cross-situational statistical correspondences between language and the environment, without any instruction. German-speakers learned SV agreement worse than other morphological features, which were acquired equally effectively by English or Mandarin speakers, indicating the subtle and varied influence of L1 morphological richness on implicit non-native language learning.

The present study describes a new Ditylenchoides species, isolated from Meknès, Morocco, during nematode surveys conducted to investigate the biodiversity of plant-parasitic nematodes in Mediterranean olive groves and adjacent patches of natural vegetation. Application of integrative taxonomical approaches clearly verified that it is a new species designated herein as Ditylenchoides morocciensis sp. nov., also representing the first report of the genus in Morocco. The new species is parthenogenetic, characterised by a short body 460 (373–528 μm); stylet delicate, relatively short, 8.7 (8.0–9.0) μm long with rounded basal knobs; six lines in the lateral fields; median bulb of pharynx oval, muscular and valvate; secretory-excretory pore located at the level of basal pharyngeal bulb region; vulva located at 79.9 (76.9–81.3) % of body length; relatively long post-vulval uterine sac 29.1 (20.0–39.0) μm; and a subcylindrical tail 24.4 (22.0–28.0) μm long, with a bluntly rounded tip. The results of molecular analysis of D2-D3 28S rRNA, ITS rRNA, partial 18S rRNA, and cytochrome oxidase c subunit 1 (COI) gene sequences support for the new species status and clearly separated D. morocciensis sp. nov. from all other species within Ditylenchoides. Phylogenetic analyses of ribosomal markers (D2-D3 28S rRNA and partial 18S rRNA) of this study confirms that Ditylenchoides is a monophyletic genus, clearly separated from other genera within Anguinoidea.

Recent research has shown that 6-month-olds relate novel words suffixed with -s, like babs, that are embedded in passages, with just the stem bab, demonstrating an early sensitivity to morphological relatedness. This study builds on these findings by investigating the role of allomorphy in early morphological acquisition. We tested whether infants relate novel words suffixed with [-z] and [-s] allomorphs of the -s suffix and their stems. We find that English-learning 6-month-olds relate novel words suffixed with the [-z], but not [-s], allomorph with stems, providing evidence for an acquisition trajectory where infants discover morphemes one allomorph at a time.

Cryphodera guangdongensis n. sp. was collected from the soil and roots of Schima superba in Guangdong province, China. The new species is characterised by having a nearly spherical female, with dimensions of length × width = 532.3 (423.8–675.3) × 295.6 (160.0–381.2) μm, stylet length of 35.7 (31.1–42.1) μm, protruding vulval lips, a vulval slit measuring 54.2 (47.4–58.9) μm, an area between the vulva and anus that is flat to concave, and a vulva–anus distance 49.3 (41.1–57.6) μm. The male features two lip annules, a stylet length of 31.7 (27.4–34.8) μm and basal knobs that are slightly projecting anteriorly, while lateral field is areolated with three incisures and spicules length of 27.1 (23.7–31.0) μm. The second stage juvenile is characterised by a body length of 506.1 (441.8–564.4) μm long, two to three lip annules, a stylet length 31.2 (29.7–33.2) μm which is well developed, basal knobs projecting anteriorly, a lateral field that is areolate with three incisures, and a narrow rounded tail measuring 63.2 (54.2–71.3) μm long, with a hyaline region of 35.6 (27.4–56.6) μm long that is longer than the stylet. Based on morphology and morphometrics, the new species is closely related to C. sinensis and C. japonicum within the genus Cryphodera. The phylogenetic trees constructed based on the ITS-rRNA, 28S-rRNA D2–D3 region, and the partial COI gene sequences indicate that the new species clusters with other Cryphodera species but maintains in a separated subgroup. A key to the species of the genus Cryphodera is also provided in this study.

Homophonous morphs have been reported to show differences in acoustic duration in languages such as English and German. How common these differences are across languages, and what factors influence the extent of temporal differences, is still an open question, however. This paper investigates the role of morphological disambiguation in predicting the acoustic duration of homophones using data from a diverse sample of 37 languages. Results indicate a low overall contribution of morphological affiliation compared to other well-studied effects on duration such as speech rate and Final Lengthening. It is proposed that two factors increase the importance of homophony avoidance for the acoustic shape of morphs: crowdedness (i.e. the number of competing homophones) and segmental make-up, in particular the presence of an alveolar fricative. These findings offer an empirically broad perspective on the interplay between morphology and phonetics and align with the view of language as an adaptive and efficient system.

This paper presents a study focusing on the morphological variations in Southwestern Norwegian preschool children’s role-play register. Within this register, the children switch between their local Southwestern Norwegian dialect and a Central Eastern Norwegian variety similar to the Oslo dialect. Although the majority of the children (with the exception of two) employ this Central Eastern Norwegian variety in role-play, two children exhibited a significantly greater degree of usage compared to the others. Consequently, these two children were selected for an in-depth analysis. The detailed analysis reveals that while the Central Eastern Norwegian variety is used for most variables by both children, the extent to which they code-switch depends on the individual child and the specific variable in question. The observed variation across variables and between the children is examined and discussed in the paper.

Detection approaches based on environmental DNA (eDNA) are widely used for free-living species but remain underutilized for parasite species. This study applies eDNA detection methods to elucidate the life cycle of the trematode Curtuteria arguinae, which infects the socioeconomically and ecologically important edible cockle (Cerastoderma edule) as its second intermediate host along the northeastern Atlantic coast, including Arcachon Bay, France. The first intermediate and definitive hosts remained unknown. To identify these hosts – presumed to be a gastropod and a shorebird – we developed a quantitative PCR (qPCR)-based eDNA approach targeting partial cox1 and SSU gene regions of C. arguinae. We tested for C. arguinae eDNA presence in water samples containing separately five dominant gastropod species and fecal samples from known cockle predators, the European oystercatcher (Haematopus ostralegus) and gulls (Larus spp.), collected in Arcachon Bay. C. arguinae eDNA was only detected in water containing the needle snail (Bittium reticulatum), with cercarial emergence confirming infection in 1.6% of individual hosts. Morphological analysis of the cercarial and metacercarial stages revealed variability in collar spine visibility. Additionally, C. arguinae was detected by qPCR in 42% of oystercatcher feces and no gull feces, suggesting oystercatchers are the definitive host. This study is the first to elucidate the complete life cycle of C. arguinae, identifying B. reticulatum as its first intermediate host and H. ostralegus as its definitive host. Our findings highlight the potential of eDNA approaches for resolving parasite life cycles and enabling advances in ecological research on C. arguinae.

The caryophyllidean tapeworm Khawia armeniaca has long been regarded as an exceptionally widespread species within its genus, notable for its significant morphological variability. However, with the accumulation of molecular data from different fish hosts, K. armeniaca was suspected to represent a species complex. To clarify the true identity of these parasites, a comprehensive morphological and molecular study (using 18S, 28S and ITS2 ribosomal regions) of K. armeniaca tapeworms from barbels (Barbinae) across the Iberian Peninsula and the Middle East has been conducted. The results revealed two genetically distinct lineages within the K. armeniaca complex. The first lineage, found in Arabibarbus grypus, Barbus lacerta, Capoeta birunii, Carassobarbus luteus, Luciobarbus barbulus, L. esocinus and L. kersin in Iraq and Iran, is genetically congruent with K. armeniaca (Cholodkovsky, 1915), originally described from the Sevan khramulya (Capoeta sevangi) in Armenia. The second lineage, identified in Luciobarbus bocagei (type host), L. comizo and L. guiraonis from Portugal and Spain, is described as Khawia iberica n. sp. In addition to clear molecular divergence, K. iberica can be distinguished from K. armeniaca by notable morphological differences, including variations in the shape, structure and size of the ovary, the anterior extension of the vitelline follicles, the testes and several morphometric parameters.

Avian trypanosomes (Trypanosoma, Kinetoplastea) are successful blood parasites occurring worldwide. These parasites are usually non-pathogenic to their avian hosts, thus neglected in studies regarding their life cycles and vectors. Several families of blood-sucking dipteran insects, including mosquitoes, have been identified as vectors of avian trypanosomes. Mosquitoes have been experimentally confirmed as vectors of Trypanosoma culicavium and Trypanosoma thomasbancrofti. In this study, we describe a third species of avian trypanosomes occurring in mosquitoes, designated as Trypanosoma tertium n. sp. This species can be distinguished from related trypanosome species based on morphology and small subunit rRNA gene sequence. Two isolates of T. tertium n. sp. obtained from a mosquito and a bird host were able to infect two subspecies of laboratory Culex pipiens mosquitoes, with infection rates reaching 60% and heavy infections in 90% of positive females. In infected mosquitoes, trypanosomes occurred as long epimastigotes in the midgut and short epimastigotes and rosettes in the hindgut. Putative infectious stages were detected in the diuretic liquid of infected mosquitoes, suggesting, besides transmission through ingestion of the infected vector, a possible transconjunctival infection. Among wild mosquitoes, avian trypanosomes were detected exclusively in Cx. pipiens with 3.3% total prevalence, while T. tertium n. sp. prevalence was only 0.08% among 1128 dissected Cx. pipiens individuals. In birds, T. tertium n. sp. was detected in 8 species within which the prevalence was 1.3% (686 birds), while it was 0.3% in total (3084 birds). We discuss the relationship of the newly described T. tertium n. sp. with other mosquito-transmitted trypanosomes.

A model for groundwater silicification within the Sables de Fontainebleau in sub-contemporary landscapes in the Paris Basin proposed 35 years ago has since been continuously and substantially updated, particularly with reference to new studies that relate silica precipitation to periglacial climate conditions. Herein we link the various distinctive morphologies of silicified sandstone bodies to the flow paths of groundwaters that imported the silica, the conditions under which it was precipitated, and the patterns of iced ground. The silicified masses are, in a way, fossil groundwater flow paths. The spatial arrangements of these paleo-groundwater flow paths suggest that permafrost developed to significant depth in parts of the Paris Basin. Our model visualizes a gradual settlement of periglacial conditions in the landscape starting with (1) cooling of the near-surface regolith and development of horizontal silicified pans; (2) progressive descent of impermeable permafrost as glacial conditions persisted, leading to non-horizontal flows ‘forced’ beneath the frozen layer; (3) thickening of the permafrost and consequent pressurization of groundwater in the phreatic zone when groundwater outflows to the valleys froze and closed, and convoluted silicified masses and possibly vertical dikes were formed; (4) followed by later thawing of the permafrost and a reduction in hydrostatic level due to climate warming leading to growth of geotropic silicified bodies when residual permafrost remained at depth. In this context, the distinctive morphologies of the silicified sand masses are proxies for the paleohydrology that prevailed during silicification and constitute a new toolbox for determining the depths reached by permafrost at time of silicification.

The East Asian region has seen the first discovery of trematodes of the genus Psilotrema in the muskrat Ondatra zibethicus. When studying the morphology of the trematodes, two morphotypes were identified among individuals of Psilotrema spp., the differences between which at the morphological level are equivalent to those between species. The affiliation of one of these morphotypes with the bird parasite Psilotrema limosum was established based on partial sequences of genes coding for 28S ribosomal RNA, nad1, and cox1 mitochondrial DNA. Based on the analysis of these three markers, we classified individuals with this morphotype as P. limosum, despite some morphological features of worms infecting birds. At the same time, the worms with second morphotype had no interspecies differences based on the first two markers, while the cox1 gene confirmed the separation of these samples on a species level. These trematodes were described as a new species, Psilotrema elegans n. sp., based on both morphological and molecular data.

The present study describes a new Mediterranean terebellid, Spinosphaera latachaeta sp. nov., found along the Aegean coast of Türkiye and the Sea of Marmara, between 27 and 80 m depth in soft substrata. It can be morphologically distinguished from all other species of Spinosphaera having 18 pairs of notopodia, double rows of uncini present until the last notopodia, and 11 pairs of Spinosphaera-chaetae. A dichotomous taxonomic key and a table summarizing the morphological characters that distinguish all species of Spinosphaera are provided. This study also reports, for the first time, the transformations of Spinosphaera-chaetae and saw-like chaetae from the anterior to posterior segments of body.

ZooBank: urn:lsid:zoobank.org:pub:628B1F01-166A-4E26-9C42-39D0CBFDE998.

This paper focuses on two phenomena in Irish agreement – namely, complementarity between overt in-situ arguments and agreement, and the obviation of this complementarity under A-movement. An analysis of these facts is offered in terms of the defective goal ‘incorporation’ (DGI) mechanism proposed by Roberts (2010), and applied to cases of complementarity in Bantu languages by Iorio (2014), and van der Wal (2015, 2020, 2022), as well as asymmetric chains under A-movement, consisting of a full copy and a pronominal $ \phi $-feature bundle; cf. similar configurations discussed by Takahashi & Hulsey (2009), Harizanov (2014), Kramer (2014), Baker & Kramer (2018), inter alios. It is shown that this approach accounts for the facts in Irish and that the same account can be extended to explain facts concerning participial agreement in, for example, Italian. Additional cross-linguistic implications are also considered, particularly with respect to French and Welsh.