Morphological Distinction Research Articles

Anatomical and histological study on the tongue of two different species Ptychadena mascareniensis and Hemidactylus turcicus from the Egyptian environment

BackgroundThe tongue plays definite and important role in simplifying food intake and also, exhibits significant morphological distinctions to acclimatize the environment. This study aimed to investigate the variations in gross and microscopic anatomy of the tongue in two tetrapod classes Ptychadena mascareniensis from class: Amphibia and Hemidactylus turcicus from class: Reptilia to correlate the structure and functions of the tongue in relations to the habitat and feeding mechanisms.ResultsAll the modifications perceived in the tongues of the premeditated animals explained the relationship between adaptation of each animal to its feeding habit and habitat. Amphibians which live in and nearby freshwater showed no keratinization in their lingual epithelium. However, reptiles, which live in terrestrial habitats, have shown keratinization and ideal forms of lingual papillae which considered the most remarkable feature of the histological structures of the reptilian tongues and reflect their adaptations to the dry habitat in which they live.ConclusionThere were some variations reported in histological structure, gross anatomy and ultrastructure morphology of the tongue from the two tetrapod classes, the Amphibia (Ptychadena mascareniensis) and Reptilia (Hemidactylus turcicus). The present study is the first one in Egypt that deals with the tongue structures and functions in one of the amphibians Ptychadena mascareniensis. Concerning the lizard Hemidactylus turcicus.

Using elemental staining and mapping techniques for simultaneous visualization of biological structures in the nucleus by multichannel electron microscopy.

Transmission electron microscopy (TEM) has been essential in defining the structural organization of the cell due to its ability to image cell structures at molecular resolution. However, the absence of colour has made it very difficult to compare the distributions and relationships of two or more types of biomolecules simultaneously if they lack clear morphological distinctions. Furthermore, single-channel information limits functional analysis, particularly in the nucleoplasm, where fibrillar material could be chromatin, ribonucleic acid or protein. Where specific stains exist to discriminate among these molecules, they cannot be combined because conventional TEM is a single-channel technology. A potential path around this barrier is through electron spectroscopic imaging (ESI). ESI can map the distributions of chemical elements within an ultrathin section. Here, we present methods to stain specific molecules with elements that ESI can visualize to enable multichannel electron microscopy.

Review: The different adaptive trajectories in Neanderthals and Homo sapiens and their implications for contemporary human physiological variation

Neanderthals are our one of our closest evolutionary cousins, but while they evolved in Eurasia, we (anatomically modern humans, AMH) originated in Africa. This contrasting evolutionary history has led to morphological and genetic distinctions between our species. Neanderthals are characterised by a relatively stocky build, high body mass, proportionally wide bodies and shorter limbs, a bell-shaped ribcage with a wide pelvis, and a long, low cranial vault compared with AMH. Classic readings of Neanderthal morphology link many of these traits to cold climate adaptations, however these interpretations have been questioned and alternative hypotheses including behavioural factors, dietary adaptations, locomotor specialisations, evolutionary history and neutral evolutionary processes have been invoked. Compared with AMH, Neanderthals may have been adapted for strength and power rather than endurance and may have consumed a diet high in animal products. However, reviewing these hypotheses highlights a number of limitations in our understanding of contemporary human physiology and metabolism, including the relationship between climate and morphology in AMH and Neanderthals, physiological limits on protein consumption, and the relationship between gut morphology and diet. As various relevant factors are clearly linked (e.g. diet, behaviour, metabolism, morphology, activity), ultimately a more integrated approach may be needed to fully understand Neanderthal biology. Variation among contemporary AMHs may offer, with caveats, a useful model for understanding the evolution of both Neanderthal and modern human characteristics, which in turn may further deepen our understanding of variability within and between contemporary humans.Neanderthals; Anatomically modern humans; morphology; climate adaptation; power adaptations; metabolism; diet; physiology; endurance running;

Triatoma yelapensis sp. nov. (Hemiptera: Reduviidae) from Mexico, with a Key of Triatoma Species Recorded in Mexico

Thirty-four species of Triatominae (Hemiptera, Reduviidae) are recorded in Mexico, Triatoma Laporte, 1832 the most speciose genus in this country. Here, we describe Triatoma yelapensis sp. nov. from the Pacific coast of Jalisco (Mexico). The most similar species to T. yelapensis sp. nov. is T. recurva (Stål, 1868), but they differ in head longitude, the proportion of labial segments, coloration pattern of corium and connexivum, spiracles location, and male genitalia. To provide statistical support for the morphological distinctiveness of the new species, we performed a geometric morphometric analysis of T. yelapensis sp. nov., T. dimidiata s.s. (Latreille, 1811), T. gerstaeckeri (Stål, 1859), and T. recurva (Stål, 1868), considering head morphology. We also provide an updated key of the genus Triatoma for species recorded in Mexico.

A New Combination for a Narrowly Endemic Polemonium (Polemoniaceae)

Based on recent molecular work, Polemonium occidentale Greene subsp. lacustre Wherry (Polemoniaceae) is elevated to species rank as P. lacustre (Wherry) J. P. Rose & Sytsma. Key morphological distinctions between this and other species of the clade to which it belongs are summarized.

An Evaluation of Landmark-Based Methods to Explore Tooth Score Morphology: A Case Study on Felids and Hyenids

Taphonomic studies aim to identify the modifying agents that intervene in bone assemblages found at archaeopaleontological sites. Carnivores may modify, accumulate, or scavenge skeletal parts inflicting tooth marks, including scores, on the cortical surface. Several works have studied tooth score morphology to discern which carnivore group modified the bone assemblages, achieving different results. In the present study, different methods based on the use of landmarks and semilandmarks have been tested to describe and analyze the score profile cross-sections of spotted and brown hyenas, leopards, and lions. According to our results, the already published seven-landmark method is useful in order to differentiate between carnivore species from different families (e.g., felids and hyenids). Meanwhile, felid species (e.g., leopards and lions) cannot be consistently distinguished using any of the methods tested here. In contrast, hyenid species can be morphologically differentiated. On the other hand, the use of semilandmarks does not generally improve morphological characterization and distinction, but low numbers of landmarks and the inclusion of the score’s deepest point might provide the best results when semi-automatic semilandmark models are preferred to avoid sampling biases.

Contribution to the knowledge of the genus Boucheona (Oligochaeta, Hormogastridae) in France with a newly described species and a redescribed species

Hormogastrid earthworms are found in the diversity hotspot of the Franco-Iberian domain, together with the better-known family Lumbricidae. Integrative systematics (the combination of morphological, molecular and ecological data) have increased our knowledge of the diversity and evolutionary history of these earthworms, highlighting unresolved taxonomic conflicts. One example of a species group in need of integrative taxonomic revision is the genus Boucheona in France. In this work, we analyzed their diversity using previously published data together with additional data obtained from recently sampled localities. Molecular data including DNA barcodes and additional markers enabled us to reconstruct Bayesian and time-calibrated phylogenies to discuss the evolutionary relationships among the different taxa, and to propose hypotheses regarding their biogeographical history. Based on our results, four species of Boucheona are present in Southern France, including two new taxa. Morphological distinctness and molecular phylogenetics results supported the status of four populations as the newly described Boucheona corbierensis sp. nov., as well as the status of "Hormogaster pretiosa var. nigra" as an independent species, redescribed as Boucheona tenebrae sp. nov. These results provide a new perspective of the importance of the genus Boucheona in southern France, as the possible evolutionary origin of a clade of giant anecic earthworms with unknown (but probably remarkable) impact on ecosystem functioning across their range.

Novel data support validity of Phoxinus chrysoprasius (Pallas, 1814) (Actinopterygii, Leuciscidae)

The common minnow species Cyprinus chrysoprasius, previously synonymised to Phoxinus phoxinus, was originally described from the Crimean Peninsula (Black Sea – Sea of Azov basin). A genetic analysis of the mitochondrial cytochrome oxydase 1 in the context of a phylogenetic study of European Phoxinus showed that it represents a distinct genetic clade and potentially a valid species. In the present study, we approach the issue following a broader, both genetic and morphological, study in order to check and support the validity of native Crimean Phoxinus under the earliest available name of the species: P. chrysoprasius. Our data demonstrate a reliable genetic distance of this minnow from geographically neighbouring clades and species, and a certain morphological distinctiveness. In order to determine the taxonomic concept of P. chrysoprasius, as a species involved in a genetically well-differentiated, but phenotypically poorly structured complex of east-European Phoxinus, a neotype for the species, based on topotypical material, is herein described and designated. The original type locality of the species is also clarified.

NEW DATA ON HESPERORNITHIDS (AVES: ORNITHURAE) FROM THE CAMPANIAN OF THE LOWER VOLGA REGION (LATE CRATACEOUS, RUSSIA)

Taxonomic diversity of the Late Cretaceous Hesperornithidae (Aves: Hesperornithidae) of the European part of Russia and Eastern Europe as a whole remain poorly understood, and the morphology of these large flightless birds is poorly known. New finds of Hesperornithidae in the Karyakino locality (Saratov oblast, Russia) confirm the coexistence of two forms of these flightless seabirds in the Campanian (mid-Late Cretaceous) of the Lower Volga region. For Hesperornis rossicus Nessov et Yarkov, 1993, a femur is described for the first time; it indicates a morphological distinctiveness of this large species as compared to the North American H. regalis Marsh, 1872.

A new species of small-eared shrew (Soricidae, Cryptotis) from El Triunfo Biosphere Reserve, Chiapas, Mexico

Abstract The Cryptotis goodwini species group of small-eared shrews (Eulipotyphla, Soricidae) includes at least 12 species discontinuously distributed in the cloud forests from southern Mexico to Honduras. Its taxonomy is still under study, with several species described only in the last decade. Previous genetic studies have highlighted that a population from El Triunfo Biosphere Reserve in Chiapas, Mexico, previously assigned to C. goodwini, is evolutionarily divergent from the other known species. However, the available specimens from this region have not been examined rigorously. Herein, I use morphological and biogeographic analyses to evaluate the taxonomic status of this population. The results confirm that it is an independent lineage, which I describe here as a new species endemic to Mexico. Overall, this is the largest shrew within the C. goodwini group. Its morphological and genetic distinction is probably due to long-term geographic isolation in the mountains of El Triunfo. I present what is now the first and only record of C. goodwini (sensu stricto) for Mexico. Finally, I identify some priority regions to direct field surveys on the C. goodwini species group to better understand its richness and distribution.

Problematic putative pachycephalosaurids: Synchrotron µCT imaging shines new light on the anatomy and taxonomic validity of Gravitholus albertae from the Belly River Group (Campanian) of Alberta, Canada

The taxonomic validity of the holotype and sole specimen of the pachycephalosaurid Gravitholus albertae (TMP 1972.027.0001) from the Belly River Group (Alberta, Canada), remains unresolved forty years after its first description. The diagnosis for this species is tenuous at best and extensive cranial fusion has prevented a thorough description and taxonomic referral of TMP 1972.027.0001. We used synchrotron µCT imaging to identify fused sutures and segment the individual elements that comprise TMP 1972.027.0001. This allowed for a detailed description of the specimen in a more thorough comparative framework with other known pachycephalosaurid specimens. Using new observations of contacts between cranial elements, the morphological distinction of TMP 1972.027.0001 from other Belly River Group pachycephalosaurids was tested with bivariate and multivariate morphometric analyses. TMP 1972.027.0001 is morphologically consistent as an end-stage semaphorant of Stegoceras validum. Furthermore, we find no taxonomically significant morphometric distinctions between Gravitholus albertae, Hanssuesia sternbergi, and Stegoceras validum, and propose the former two are synonymous with the later. Large Stegoceras validum frontoparietals show statistically significant dimorphism in the thickness of the frontonasal boss, which is not apparent amongst juvenile and subadult specimens. Pathologies consistent with intraspecific combat (“headbutting”) appear restricted to frontoparietal domes with proportionally taller frontonasal bosses, and suggests that the two morphs represent sexual dimorphs, rather than separate species. Foraminacephale brevis and Stegoceras validum are the only named pachycephalosaurids recognised in the Dinosaur Park Formation. The stratigraphic and temporal range of Stegoceras validum is extended into the underlying Oldman Formation. Pachycephalosaurid diversity in the Campanian is reduced as a result of these revised taxonomic hypotheses. A revised phylogenetic character matrix, recognising taxonomic synonymies and ontogenetically dependent character states results in a largely unresolved Pachycephalosauria.

A new nematode of the family Capillariidae identified in Cairina moschata (Linnaeus) on Marajó Island in the Brazilian Amazon.

Capillaria Zeder, 1800, parasitizes the organs and tissues of several hosts, including the domestic duck Cairina moschata (Linnaeus). This article describes a new species of Capillaria in domestic ducks identified based on morphological studies and molecular analyses of the ribosomal RNA gene. Thirty-eight specimens of C. moschata from the municipality of Soure, Marajó Island, Pará, Brazil. The organs of the birds' digestive tract were analyzed under a stereomicroscope to confirm the parasitic infection, after which the collected nematodes were identified by light microscopy, scanning electron microscopy, and molecular analysis. Capillariids parasitized the intestine and cecum of the examined birds. These parasites had three bacillary bands and a pair of elongated precloacal papillae on the tail. Phylogenetic analysis indicated that the new species formed a sister clade with Capillaria spinulosa (Linstow, 1890), as described in Indonesia and Japan. Based on morphological distinctions and molecular data, Capillaria cairina n. sp. can be considered a new parasite species of C. moschata in the Brazilian Amazon.

Hidden in the fog: morphological and molecular characterisation of Derogenes varicus sensu stricto (Trematoda, Derogenidae) from Sweden and Norway, and redescription of two poorly known Derogenes species.

Derogenes varicus (Müller, 1784) is widely reported as a trematode with exceptionally low host specificity and a wide, bipolar distribution. However, several recent studies have suggested that D. varicus represents a species complex and based on molecular evidence, four genetic lineages (labeled as "DV1-4") have been designated within the D. varicus species complex. This possibility requires improved (ideally molecular) characterisation of specimens from the type-host (Salmo salar) and type-locality (off Denmark). During examination of trematode parasites of fish from Scandinavian and Arctic waters (Sweden and Norway), we found specimens of D. varicus in the stomach of Merlangius merlangus off the coast of Sweden, and in Gadus morhua off the coast of Sweden and Norway; we compared them to D. varicus from the type-host, the Atlantic salmon Salmo salar fromNorway, to verify their conspecificity. Newly generated sequences (28S rDNA, ITS2 and cox1) of Scandinavian and Arctic specimens consistent with D. varicus all formed a single clade, DV1. 28S sequences of D. varicus from S. salar from Norway, i.e., close to the Danish type locality, clustered within the DV1 clade along with sequences of D. varicus from various hosts including Limanda limanda, G. morhua and Myoxocephalus scorpius from the White Sea and the Barents Sea (Russia), without any host-related structuring. We thus consider that the lineage DV1 represents D. varicus sensu stricto. Additionally, specimens from M. merlangus had a similar morphology and anatomy to those of D. varicus from L. limanda, G. morhua and M. scorpius from T. Odhner's collection, supporting the presence of a single species in the DV1 lineage designated herein as D. varicus sensu stricto. We redescribe D. varicus sensu stricto, add new morphological characters and provide morphometric data. We infer that D. varicus types DV2-4 all relate to separate species. We also revise type-specimens of Derogenes minor Looss, 1901 from the A. Looss collection in the Swedish Museum of Natural History and provide redescriptions of it and of the type-species of the genus, Derogenes ruber Lühe, 1900. In light of their morphological distinctiveness relative to D. varicus sensu stricto, we reinstate D. parvus Szidat, 1950 and D. fuhrmanni Mola, 1912.

On the emergence of inflection classes

Laz has a rich verb classification system. While the language presents robust morphological correlates of argument structure, it also exhibits finer morphological distinctions that have been argued to encode less canonical semantic features. This paper argues that these distinctions merely constitute inflection classes in the synchronic grammar of Laz but could be a residue of a grammar where these semantic features were active in exponent selection.

Molecular and morphological evidence support the recognition of three genera within Radulaceae (Porellales: Marchantiophyta)

The discovery of new fossil bryophytes allows refined estimates of divergence times when the fossils have unambiguous synapomorphies enabling their confident assignment to nodes within molecular phylogenies. We use two fossil Radula species from Cretaceous age Burmese amber to estimate divergence times for Radula. One of these fossils, R. cretacea which has synapomorphies of subg. Odontoradula, has been used previously; the other, with relative synapomorphies of subg. Amentuloradula, has not. In combination these two fossils, when used to constrain the crown node age of their respective subgenera, result in median age estimates for the Radula crown node of 263 million years, under our preferred time-calibration scenario where subgeneric crown-node fossil assignments are coupled with a secondary maximum age constraint on the Porellales crown node. We explore other time-calibration scenarios, including deeper fossil assignments, and conclude that, under all, Radula as currently circumscribed is an outlier among land plant genera on the basis of its age. While this violates no established norms regarding how old genera should be, the absolute age, the relative ages of other families within Porellales, and the morphological distinctiveness of the two serial sister lineages, subg. Cladoradula, with seven species, and subg. Dactyloradula with one species, motivates our proposal to elevate these two subgenera to generic rank, resulting in three genera within the family Radulaceae. We provide diagnoses for genera, new combinations for species, and an emended circumscription for Radula, that reflect this change.

Phylogenetic and morphological analysis of Gloydius himalayanus (Serpentes, Viperidae, Crotalinae), with the description of a new species

Gloydius is a widespread pitviper group occurring from Eastern Europe to Korea and Siberia, with only one known species, G. himalayanus (Günther, 1864), found south of the Himalayas. We provide combined genetic and morphological data for G. himalayanus from specimens collected from Himachal Pradesh, India. Bayesian Inference and Maximum Likelihood phylogenetic analysis were performed on four concatenated mitochondrial genes, along with a multi-locus coalescent analysis of these and five additional nuclear genes. Our results indicate that G. himalayanus from the Chamba Valley, in western Himachal Pradesh, are highly distinct from the remaining studied populations. Haplotype networks of each nuclear locus showed that G. himalayanus contains high haplotype diversity with low haplotype sharing between the Chamba Valley population and populations from further west. Principal component analysis and canonical variate analysis conducted on morphological data of live and museum specimens also highlight the morphological distinctiveness of the Chamba population and we herein describe this population as a new species, Gloydius chambensis sp. nov. Recent descriptions of other new species of snakes from this valley underscores its isolation and suggests that further herpetological investigation of the highly dissected landscapes of the western Himalayas is needed to assess the true diversity of the region.

Regional environmental and climatic concerns on preserving native gene pools of a least concern species: Brown trout lineages in Mediterranean streams

The European brown trout, Salmo trutta, is a cold-adapted fish reported as a Least Concern species in the IUCN Red List. This species colonized new territories from southern refuges during the last glacial melting, but during the 20th century suffered from anthropic impacts on its habitats. The long-time survival of the species relies on the genetic diversity within and among populations. Brown trout is among the genetically most diverse vertebrate species; however, native populations in Mediterranean rivers have dramatically suffered of introgressive hybridization from extensive releases of evolutionary distant non-native Atlantic stocks. In addition, in Mediterranean rivers climate change will result in unsuitable conditions for the species during the 21st century. Using brown trout populations at the headstreams of a Pyrenean river as a model, this paper revised how hatchery releases have affected the native gene pools and how environmental and climatic variables controlled the amount of local introgression at intra-basin level. Introgressive hybridization was detected in all studied sites. Ten times larger divergence was observed among populations at tributaries than among populations along the main stem. A highly impacted population distributed in a long transect in the main stem suggested that hatchery fish move towards the main stem wherever released. From already highly impacted populations and despite the cessation of hatchery releases, warmer temperatures and lower precipitation expected from climate change will extend the introgressive hybridization along the basin, contributing to the extinction of the native gene pools. Based on available morphological distinction of native, hatchery and hybrid brown trout, we advocate the involvement of regional social groups (e.g. riverside dwellers, anglers, conservationists, hikers) in citizen science programs to detect the spread of non-native phenotypes along the rivers. These are cheap and fast methods to collaborate with fishery managers in the preservation and recovery of the regional native populations.

Morphological variation between the two species of the palm genus Gaussia (Arecaceae) from Mesoamerica

Palms (Arecaceae) represent a challenge for studies of morphological variation for several various reasons. For instance, the height of many species makes them difficult to collect, and in some cases, the size of the leaves or the presence of spines make them hard to process and preserve in herbaria. Arecaceae is one of the most diverse families of monocots (ca 2600 species), and many of its species remain poorly studied. The genus Gaussia has five recognized species. Their distributions are restricted to Central America and the Caribbean islands, and for most of them, their taxonomic descriptions are the only information available. Two species – Gaussia maya and G. gomez‐pompae – are exclusively distributed in Mesoamerica. They occur allopatrically and their populations are isolated from each other. The aim of this work was to evaluate the levels of intra‐ and inter‐population morphological variation in both species and determine the possible factors that influence such a variation. We examined the morphological variation of 13 vegetative structures of 155 adult individuals from nine populations of G. maya and G. gomez‐pompae. The differentiation among populations was significant for almost all the variables and was consistent with an isolation‐by‐distance pattern. A linear discriminant analysis, Mahalanobis distances and UPGMA cluster analysis based on Euclidean distances among populations showed that three morphological groups could be distinguished. One group contained only individuals of G. maya, the second only G. gomez‐pompae, while the third group represents a yet unknown taxon. Pairwise differentiation tests clarified the morphological distinction among the three groups. This work highlights the importance of quantifying morphological variation between populations of little‐studied palms.

Blastocystis occurrence in water sources worldwide from 2005 to 2022: a review.

There has been increasing interest in the study of Blastocystis in the last two decades. Many studies have been carried out in human and animal hosts including environmental sources, but there is little or no information on the occurrence of Blastocystis in water sources worldwide. Therefore, this study aimed at assessing the occurrence of Blastocystis in water sources across the world from 2005 to 2022, noting the method of detection and the distribution of the subtypes from various water sources. A literature search was performed on internet-based databases including Google search, PubMed, Scopus, and Web of Science. Upon application of the criteria for inclusion, 25 articles revealing the occurrence of Blastocystis in water sources in 15 countries were included in the review. Blastocystis occurrence varies across water sources ranging from 0% in a drinking water source in Venezuela to 100% in rivers; well water, stored water, and fishpond in Nepal and Malaysia; and fountain water, irrigation water, and rainwater in Italy, Spain, and Thailand. The occurrence of the parasite was significantly associated with the coliform count, temperature, conductivity, dissolved oxygen, turbidity, total dissolved solids, and chemical oxygen demand. A total of 11 Blastocystis subtypes were identified in water sources worldwide, namely, ST1-ST8, ST10, ST23, and ST26 in which ST1 and ST3 were the most prevalent subtypes. Considering the importance of Blastocystis as a waterborne parasite, the subtype distribution and morphological distinction in water sources need to be carried out using molecular and electron microscopic techniques. Existing studies have covered only about 10% of the world's countries.

Molecular assessment of Ulva (Ulvales, Chlorophyta) diversity in Vietnam including the new species U. vietnamensis

SUMMARYSpecies diversity of Ulva in Vietnam was investigated using three commonly used genetic markers, the nuclear encoded rDNA ITS region and the plastid encoded rbcL and tufA genes. Single locus species delimitation methods, complemented with morphological and ecological information resulted in the delimitation of 19 species. This diversity is largely incongruent with the traditional understanding of Ulva diversity in Vietnam. Only four species identified in this study, U. lactuca, U. reticulata, U. spinulosa, and U. flexuosa, have been previously reported, and seven species, U. ohnoi, U. tepida, U. chaugulii, U. kraftiorum, U. meridionalis, U. limnetica, and U. aragoënsis, are recorded for the first time from Vietnam. Seven genetic clusters could not be associated with species names with certainty. A new species, U. vietnamensis, is described from marine to brackish coastal areas from southern Vietnam based on its morphological and molecular distinctiveness from the currently known Ulva species. A comparison with recent molecular‐based studies of Ulva diversity showed that species composition in Vietnam is similar to that of adjacent countries, including Japan, China, as well as Australia. Our study emphasizes the importance of molecular data in the assessment of Ulva diversity, and indicates that a lot of diversity may still remain to be discovered, especially in tropical regions.