High Morphological Variability Research Articles

Systematics of Urostephanus: resurrection of a Mesoamerican taxon of Gonolobinae (Apocynaceae, Asclepiadoideae), with eight new combinations

Background and Aims: Recent studies have focused on resolving the systematics of the tribe Gonolobinae of the family Apocynaceae, as well as the controversial genus Matelea s.l. However, many species within Matelea s.l. have not been evaluated phylogenetically. This is the case of M. gonoloboides, previously recognized as the type species of Urostephanus, and other taxa with similar floral morphology. The aim of this study is to test the monophyly of Urostephanus, including some species with morphology similar to M. gonoloboides. Furthermore, we evaluate the taxonomic position of the Urostephanus clade within the subtribe Gonolobinae and compare morphology among related clades. Methods: To assess phylogenetic relationships within Gonolobinae, we downloaded sequences from four loci for 94 species of the subtribe from GenBank. We extracted DNA and sequenced the trnL-F intergenic spacer and rps16 intron from four species of Dictyanthus and six species of Matelea, which are considered to belong to Urostephanus. We reconstructed the phylogeny with Bayesian inference using the maximum clade credibility tree. Based on the phylogenetic pattern, we performed morphological comparisons between the clades Dictyanthus, Polystemma, and Urostephanus. Key results: Phylogenetic analysis recovered Urostephanus as monophyletic and sister to Dictyanthus. Based on this phylogenetic pattern and floral morphology, we resurrect the genus Urostephanus. We propose eight new combinations for the species included in the phylogeny, as well as for those that share floral morphological similarity. We designate two lectotypes. Finally, we discuss aspects of morphology between Urostephanus and closely related groups. Conclusions: The current circumscription of Matelea s.l. includes species with high morphological diversity. With the phylogenetic and morphological evidence among related taxa, we support the resurrection of Urostephanus, more than 120 years after its description. These results contribute to the resolution of the systematics of Gonolobinae in Mesoamerica.

Environment, intraspecific lineages and geographic range jointly shape the high morphological variability of Dikerogammarus villosus (Sowinsky, 1894) (Crustacea, Amphipoda): a successful aquatic invader across Europe

AbstractPhenotypic variability is a key factor promoting the establishment and spread of invasive populations in new environments. The Ponto-Caspian region contains a diverse endemic fauna known for its exceptional environmental plasticity, with many species invading European waters. However, the extent to which the environment shapes the phenotypic variability of these successful invaders remains poorly understood. We test to what extent the environment, intraspecific lineage affinity and geographic range interact and shape the variability of ecologically relevant functional morphological traits of the amphipod, Dikerogammarus villosus. Our results show the highest differentiation among environments, with an enhancement of predation-related traits in brackish waters relative to freshwaters. Differentiation among lineages and ranges (native/invaded) was smaller, occurring in traits related to locomotion and food processing. Although we uncovered an overall increase in variability outside the native range, the dynamics of morphological change were lineage-specific: the Western Lineage (invading via the River Danube) underwent a shift towards increased appendage length, while the Eastern Lineage (invading via the River Dnieper) underwent a significant overall morphospace expansion. We conclude that D. villosus exhibits a remarkable morphological variability across Europe that is influenced by the interplay between the environment as well as its evolutionary and invasion history.

An integrative approach highlights the discrepancy in the genetic, phenotypic, and presumptive taxonomic structure of Phoxinus (Actinopterygii, Leuciscidae, Phoxininae) in Bulgaria.

The present drainage network of Bulgaria is the result of a complex Neogene and Quaternary evolution. Karst, which has developed on 23% of the territory, further complicates the hydrological pattern. Fresh waters of Bulgaria drain into the Black Sea and the Aegean Sea basins and can be roughly divided into the Danube (Middle and Lower Danube), non-Danube Black Sea, East Aegean, and West Aegean hydrological regions. Phoxinus, a small leuciscid fish, has a mosaic distribution in all four of these regions, inhabiting small mountainous and semi-mountainous streams. Based on morphology, it was identified as three species, Phoxinus phoxinus in the Danube, Phoxinus strandjae in the non-Danube, and Phoxinus strymonicus in West Aegean region. Later, molecular data revealed Phoxinus csikii and Phoxinus lumaireul in the Middle Danube and P. csikii in the Lower Danube. Phoxinus has been the focus of many studies, showing a high molecular and morphological diversity, which is not entirely consistent with previous morphology-only-based taxonomic concepts. In this study, molecular (a mitochondrial marker and a nuclear marker) and morphological data from both historical and recently sampled collections were analysed to assess the applicability of the integrative approach in Phoxinus. The results showed a significant influence of the complex paleo- and recent hydrology on the currently observed genetic structure of the considered populations and species. Furthermore, the study also demonstrated a strong influence of phenotypic plasticity on the morphological analysis of Phoxinus and the lack of a clear differentiation between P. csikii and P. strandjae. A barcoded specimen was designated as neotype to fix the species named P. strandjae in the current taxonomic concept. Finally, a significant discordance between genetically delimited clades and phenotypic groups did not allow a proper delineation of the species distributed in Bulgaria, demonstrating that more molecular markers are needed for further taxonomic study of the Phoxinus complex.

The use of 18S rRNA for identification of the first record of Tadpole Shrimp Lepidurus apus (Linnaeus, 1758) from Jordan

Abstract. Abushattal S, Alnasarat H, Alnaimat SM, Eid E. 2024. The use of 18S rRNA for identification of the first record of Tadpole Shrimp Lepidurus apus (Linnaeus, 1758) from Jordan. Biodiversitas 25: 1223-1229. The tadpole shrimps are living fossils that survive in temporary water pools and are considered benthic organisms that swim and feed on tiny organisms. Two genera of tadpole shrimps exist worldwide: Triops and Lepidurus, which share similar ecological niches and habitats but never coincide. The occurrence of the tadpole shrimp Lepidurus apus in Jordan was confirmed for the first time using the 18S rRNA Gene-Based PCR Assay. The experimental approach encompassed the amplification of biological specimens utilizing a universal amplicon measuring approximately 1,500 base pairs (bp), specifically targeting the 18S ribosomal RNA (rRNA) gene. Subsequently, the acquired sequences underwent scrutiny through BlastN search against the GenBank database for validation and comparative analysis. Genetic analysis was needed to define the species accurately, especially with tadpole shrimp's generally high morphological variability. This species was recorded in a temporary freshwater pool in the desert of Al-Jafr in Ma’an governorate in southern Jordan. The DNA analysis showed a 100% identical sequence of the 18S rRNA gene with Lepidurus apus sequences. This record is important due to the ecological role of the tadpole shrimps as filter feeders, consuming algae, bacteria, and other small particles of organic matter, and as a food source for various fish, birds, and other aquatic animals. In addition, it will pave the way for future research to identify its economic importance, such as its role in mosquito control and its potential role in aquaculture. Finally, tadpole shrimp are sensitive to environmental changes and could be used to indicate climatic changes and habitat degradation. This is mainly due to their sensitivity to changes in water quality, including temperature, pH, and chemical composition, and their niche requirements for survival and reproduction. In addition, monitoring tadpole shrimp distribution and comparing it with historical records can reveal patterns of climate-induced range shifts.

Traumatic copulation and counterpart female traits are widespread in fritillary butterflies (Lepidoptera: Nymphalidae: Argynnini)

AbstractFemale fritillary butterflies (Lepidoptera: Nymphalidae: Argynnini) are known to have diversified genital structures, especially at the entrance of the bursa copulatrix. However, the origin and function of such elaborated structures are poorly known to date. We examined the male and female genital structures of six Japanese species selected from five genera/subgenera [Argynnis (Argynnis), Argynnis (Damora), Argynnis (Argyronome), Fabriciana, and Speyeria] of the Argynnini tribe and found that traumatic copulation is widespread in Argynnini. Various male genital structures, such as the uncus, valva, and phallus, can cause wounds to the female genitalia. The eighth venter of the female, where the highest morphological diversity in female genitalia was detected, is hooked and held by the male uncus during copulation. It is very likely that the diversified female genital structure coevolved with the male uncus as a counterpart for traumatic coupling.

Morphological innovation after mass extinction events in Permian and Early Triassic conodonts based on Polygnathacea

Taxonomic diversity of marine animals decreased markedly during the end-Guadalupian and end-Permian mass extinctions, but conodonts were largely unaffected by these two major events. This conclusion is largely based on potentially problematic conodont taxonomy, but quantitative analyses of conodont morphology have received little attention, despite offering key insights into macroevolutionary dynamics. Polygnathacea conodonts seemingly evolved fast and had high morphological diversity, and are therefore ideal for exploring morphospace trends and disparity related to environmental change in conodonts. Here we compiled discrete character-taxon matrices to first refine phylogenetic interpretations and then explore morphological disparity in four related conodont families, the Anchignathodontidae, Sweetognathidae, Idiognathodontidae and Vjalovognathidae, from the Permian to Early Triassic. Our findings reveal morphological innovation and exploration of new morphospace after the end-Guadalupian mass extinction and end-Permian mass extinction. We also show that the smaller end-Guadalupian extinction event was more impactful, resulting in greater losses of morphological disparity and taxonomic diversity, than the larger end-Permian extinction event. Overall, our study reveals morphological disparity trends related to temporal evolutionary dynamics for conodonts during the geologically and environmentally turbulent Permian and Early Triassic. We show that conodonts are affected by extinction events during this interval in terms of morphological diversity, rather than simply taxonomic diversity.

A bilateral four-headed brachialis muscle with a variant innervation: a cadaveric report with possible clinical implications.

Anterior compartment muscles of the arm present high morphological variability, with possible clinical significance. The current cadaveric report aims to describe a bilateral four-headed brachialis muscle (BM) with aberrant innervation. Emphasis on the embryological background and possible clinical significance are also provided. Classical upper limb dissection was performed on an 84-year-old donated male cadaver. The cadaver was donated to the Anatomy Department of the National and Kapodistrian University of Athens. On the left upper limb, the four-headed BM was supplied by the musculocutaneous and the median nerves after their interconnection. On the right upper limb, the four-headed BM received its innervation from the median nerve due to the musculocutaneous nerve absence. A bilateral muscular tunnel for the radial nerve passage was identified, between the BM accessory heads and the brachioradialis muscle. BM has clinical significance, due to its proximity to important neurovascular structures and frequent surgeries at the humerus. Hence, knowledge of these variants should keep orthopedic surgeons alert when intervening in this area. Further dissection studies with a standardized protocol are needed to elucidate the prevalence of BM aberrations and concomitant variants.

First record of the genus Staurocladia (Hydrozoa: Cladonematidae) in the Gulf of Mexico with the description of Staurocladia dzilamensis sp. nov., a new species of crawling hydromedusa

The Cladonematidae are a family of hydrozoans with a worldwide distribution and morphological adaptations for a benthic mode of life. Species of this family are characterized by high morphological variability, which has caused many taxonomical debates, mainly for the species of the genera Eleutheria Quatrefages, 1842 and Staurocladia Hartlaub, 1917. Herein, we describe Staurocladia dzilamensis sp. nov., a new species of crawling hydromedusa from the southern Gulf of Mexico. This finding also constitutes the first record of the genus Staurocladia for the Gulf of Mexico. The presence of additional nematocyst clusters, supplementing the apical one on the upper branch of the tentacles, places it within Staurocladia. The presence of exumbrellar buds, a conspicuous marginal ring of nematocysts, 6–11 bifid tentacles with lower branches longer than their upper counterpart, the cnidome with stenoteles of two size classes, and two nematocyst clusters on the upper branch supplementing the apical one, opposite placed alternately on its aboral and oral sides permits to differentiate S. dzilamensis from its congeners. A taxonomic key for the species of Staurocladia is provided.

Observation on local high-yielding stevia (Stevia rebaudiana Bertoni L.) clone specific to Bandung District, West Java

The use of stevia (Stevia rebaudiana Bertoni L.) as a natural sweetener shows great potential. However, in Indonesia, the lack of superior and highly productive varieties has been a major challenge in its development. Nukita Co-op has developed a promising stevia clone which we evaluated in this study for its readiness to be proposed as a new and improved variety. Our research was conducted in August 2023 through primary and secondary data collection. Primary data comprised the clone development process and morphological variations observed in farmers’ fields, while secondary data included crop productivity and types of stevia-based products made. Our findings revealed that the CM3 clone, derived from a Vietnamese variety, has been cultivated by farmers in Bandung district since 2010. It has high yields (up to 7-ton dry leaves/ha/year) and is marketed as simplisia (unprocessed ingredients) and various tea variants. However, we noted high morphological variations in farmers’ fields. Therefore, stevia clone CM3 is not ready for direct release. With breeding efforts, this clone could be improved through the selection process and released as a high-yielding variety to support stevia’s development as an alternative sweetener.

Characterization of Angraecum (Angraecinae, Orchidaceae) Plastomes and Utility of Sequence Variability Hotspots.

Angraecum, commonly known as Darwin's orchid, is the largest genus of Angraecinae (Orchidaceae). This genus exhibits a high morphological diversity, making it as a good candidate for macroevolutionary studies. In this study, four complete plastomes of Angraecum were firstly reported and the potential variability hotspots were explored. The plastomes possessed the typical quadripartite structure and ranged from 150,743 to 151,818 base pair (bp), with a guanine-cytosine (GC) content of 36.6-36.9%. The plastomes all contained 120 genes, consisting of 74 protein-coding genes (CDS), 38 transfer RNA (tRNA) genes and 8 ribosomal RNA (rRNA) genes; all ndh genes were pseudogenized or lost. A total of 30 to 46 long repeats and 55 to 63 SSRs were identified. Relative synonymous codon usage (RSCU) analysis indicated a high degree of conservation in codon usage bias. The Ka/Ks ratios of most genes were lower than 1, indicating that they have undergone purifying selection. Based on the ranking of Pi (nucleotide diversity) values, five regions (trnSGCU-trnGGCC, ycf1-trnNGGU, trnNGUU-rpl32, psaC-ndhE and trnSGCU-trnGGCC) and five protein-coding genes (rpl32, rps16, psbK, rps8, and ycf1) were identified. The consistent and robust phylogenetic relationships of Angraecum were established based on a total of 40 plastomes from the Epidendroideae subfamily. The genus Angraecum was strongly supported as a monophyletic group and sister to Aeridinae. Our study provides an ideal system for investigating molecular identification, plastome evolution and DNA barcoding for Angraecum.

Redefining the phylogenetic relationships of European Angelica (Apiaceae) species

Angelica (Apiaceae) is a large complex genus with high morphological diversity. The many taxonomic treatments explain the controversy regarding the number of European species, which range from four to ten. Molecular methods have unraveled the complicated Asian and American taxonomies; however, no comprehensive molecular study has been conducted on the European taxa. We aim to determine the number of different European Angelica s.l. taxa and their relationship within the Selineae tribe by conducting Maximum Likelihood (ML) and Bayesian Inference (BI) analyses based on the nuclear Internal Transcribed Spacer (ITS) and haplotype networks by Templeton Crandall and Sing and neighbour-net analyses based on the plastid trnL. Three separate Iberian species (A. angelicastrum, A. razulii and A. pyrenaea) form the new Iberian Angelica clade, which is sister to the Archangelica clade. Although morphologically different, A. pachycarpa cannot be differentiated from A. angelicastrum by molecular methods, casting new doubts on the existing taxonomies. Molecular evidences suggest that A. heterocarpa should be considered an estuary forma of A. sylvestris. The east and west A. sylvestris subclades support the subspecies A. sylvestris subsp. elatior and A. sylvestris subsp. villosa (including A. heterocarpa). Our evidences support the classification of A. palustris as Ostericum palustre.

TRADITIONAL KNOWLEDGE IN CONSERVATION AND FARMING PRACTICES OF WATER YAM (DIOSCOREA ALATA L.): LESSONS LEARNED FROM EAST JAVANESE COMMUNITY

Water yam (Dioscorea alata L.) is an underutilized crop but plays a crucial role in food security of small and marginal rural families. For centuries, local farmers have planned agricultural production while conserving natural resources by adopting traditional knowledge (TK). This study aims to documents the importance of TK on water yam diversity, conservation and farming practices from the East Javanese community, a case study in Tuban Regency, Indonesia. The data collection was using a purposive sampling through interviews and direct participatory activities. Results showed that at least seven water yam local varieties were recognized with high tuber morphological variations, namely Uwi Bangkulit, Uwi Putih, Uwi Legi, Uwi Ungu, Uwi Sego, Uwi Klelet, and Uwi Randu. The variety naming mostly reflects distinct morphology and perceptual characteristics. The farmer’s reasons to cultivate variety are related to the economic value and consumable preference. Three farming systems were identified including home garden, dry land agriculture and agroforestry. The cultivation patterns are adjusted to the climatic and seasonal changes for many years, with good management practices from seed and soil preparation, planting and crop maintenance, to tuber harvest, storage and marketing. Miscellaneous uses of water yam are also documented for their sustainable livelihoods. This study can serve as a framework for decision-making at local and national level for conservation efforts and further development in cultivation management and utilization of water yam.

Genome Studies in Four Species of Calendula L. (Asteraceae) Using Satellite DNAs as Chromosome Markers

The taxonomically challenging genus Calendula L. (Asteraceae) includes lots of medicinal species characterized by their high morphological and karyological variability. For the first time, a repeatome analysis of a valuable medicinal plant Calendula officinalis L. was carried out using high-throughput genome DNA sequencing and RepeatExplorer/TAREAN pipelines. The FISH-based visualization of the 45S rDNA, 5S rDNA, and satellite DNAs of C. officinalis was performed on the chromosomes of C. officinalis, C. stellata Cav., C. tripterocarpa Rupr., and C. arvensis L. Three satellite DNAs were demonstrated to be new molecular chromosome markers to study the karyotype structure. Karyograms of the studied species were constructed, their ploidy status was specified, and their relationships were clarified. Our results showed that the C. officinalis karyotype differed from the karyotypes of the other three species, indicating its separate position in the Calendula phylogeny. However, the presence of common repeats revealed in the genomes of all the studied species could be related to their common origin. Our findings demonstrated that C. stellata contributed its genome to allotetraploid C. tripterocarpa, and C. arvensis is an allohexaploid hybrid between C. stellata and C. tripterocarpa. At the same time, further karyotype studies of various Calendula species are required to clarify the pathways of chromosomal reorganization that occurred during speciation.

Disentangling the distribution of Adenostyles in the Northern Iberian Peninsula: new insights from nuclear and plastid markers

The genus Adenostyles (Asteraceae) comprises three species with high morphological variability that inhabit south Europe mountainous regions. The Iberian Peninsula harbours A. alpina subsp. pyrenaica and A. alliariae; the former (calcifugate) is restricted to western-central Pyrenees and the Cantabrian Mountains, while the latter (calcicole) is eastern Pyrenees and Sierra de Gredos. The number of taxa inhabiting the Cantabrian Mountains has remained controversial as the sole presence of A. alpina subsp. pyrenaica and the presence of both species and intermediate forms have been reported. Additionally, a recent study casted doubts on the A. alpina subsp. pyrenaica edaphic preference. We determined the number of taxa in the Cantabrian Mountains, their edaphic preference and the presence of hybrids, by conducting phylogenetic analyses based on plastid (trnL-rpL32 and trnH-psbA) and nuclear (ITS) markers. The ITS Maximum Likelihood and Bayesian Inference topologies revealed no edaphic preference for A. alpina subsp. pyrenaica. The plastid networks grouped individuals by geographical origin in the Centre of Distribution and the Peripheral groups. The plastid-nuclear and PhyloNetwork topologies suggested Incomplete Lineage Sorting (ILS) in the Peripheral group, supporting the hypothesis of Quaternary expansions and contractions. No hybrid was found in the Cantabrian Mountains, although evidence suggested gene flow between species.

Население золотоордынского времени Восточно-Причерноморского региона по данным остеометрии (по материалам раскопок могильника Натухаевское 5)

Introduction. Osteometric data of adult individuals of the anthropological series from the burial ground of the Golden Horde time "Natukhaevskoe 5" are presented for the first time in this work. Based on the standard measurements, patterns of the skeletal constitution of the buried are discussed. As part of this study, we tested the hypothesis about the difference in the morphological appearance of two samples, combined according to the type of funeral rite - stone boxes and burial grounds. Materials and methods. The anthropological collection consists of the remains of 124 adult individuals, including 67 males and 57 females. Measurements of the postcranial skeleton were carried out according to the program of R. Martin (in version by V.P. Alekseev) according to 55 features. The degree of homogeneity of the male and female samples was determined using an intragroup analysis with the method of principal components for 10 features. The Mann-Whitney test was used to assess the statistical significance of differences. Results. The male population was rather tall with a shortened robust humerus and an elongated forearm bones, the lower limbs were long and massive. Among the female group, there is also a tendency to lengthen the lower limbs, relative to the upper ones, mainly due to the lower leg. The conducted intragroup analysis did not reveal statistically significant differences between the two groups, united according to the type of funeral rite, neither among men nor among women. However, a large range of linear size variations was found among men buried in stone boxes. Compared to them, the sample from the ground pit is more homogeneous. A different picture is observed in the female sample, where higher morphological diversity can be traced among those buried in the pits. @ 2023. This work is licensed under a CC BY 4.0 license

Morphological diversity of cancer cells predicts prognosis across tumor types.

Intratumor heterogeneity drives disease progression and treatment resistance, which can lead to poor patient outcomes. Here, we present a computational approach for quantification of cancer cell diversity in routine hematoxylin-eosin-stained histopathology images. We analyzed publicly available digitized whole-slide hematoxylin-eosin images for 2000 patients. Four tumor types were included: lung, head and neck, colon, and rectal cancers, representing major histology subtypes (adenocarcinomas and squamous cell carcinomas). We performed single-cell analysis on hematoxylin-eosin images and trained a deep convolutional autoencoder to automatically learn feature representations of individual cancer nuclei. We then computed features of intranuclear variability and internuclear diversity to quantify tumor heterogeneity. Finally, we used these features to build a machine-learning model to predict patient prognosis. A total of 68 million cancer cells were segmented and analyzed for nuclear image features. We discovered multiple morphological subtypes of cancer cells (range = 15-20) that co-exist within the same tumor, each with distinct phenotypic characteristics. Moreover, we showed that a higher morphological diversity is associated with chromosome instability and genomic aneuploidy. A machine-learning model based on morphological diversity demonstrated independent prognostic values across tumor types (hazard ratio range = 1.62-3.23, P < .035) in validation cohorts and further improved prognostication when combined with clinical risk factors. Our study provides a practical approach for quantifying intratumor heterogeneity based on routine histopathology images. The cancer cell diversity score can be used to refine risk stratification and inform personalized treatment strategies.

Origin and evolution of the Neogene calcareous nannofossil Ceratolithus

Sediment samples of deep marine oceanic ODP boreholes from sites 999 in the Caribbean Sea and 1237 in the Eastern Pacific Ocean covering the period between 6 and 4.5 Ma have been studied with a focus on ceratolith evolution. Orthorhabdus rugosus is a nannolith with three blades (sinistral, median, and dextral) that first appeared during the Serravallian, it is not-birefringent in its stable orientation. It shows a high morphological variability time-interval at the end of the Messinian to the basal Pliocene (5.5 to 5 Ma) during which Ceratolithus (5.484 Ma) evolved. Changes occurred in the sinistral and median blades, whilst the dextral blade was reduced. Ceratolithus finifer n. comb is the first species of the evolutionary line. The nannolith stable position changed during its evolution, resulting in the older forms showing low birefringence and the younger ones moderate to high birefringence in the most stable orientation. Ceratolithus acutus, with an arrowhead shape, Ceratolithus armatus, and the morphologically distinct C. larrymayeri evolved from C. finifer with all three species showing high birefringence. The previous O. rugosus and C. finifer continued. Finally, C. armatus gives rise to C. cristatus. Ceratolithus atlanticus and C. tricorniculatus also evolved from C. finifer. All the species mentioned become extinct during the Pliocene except Ceratolithus cristatus that lives today. Detailed observations permit the analysis of the evolutionary trends of the group, possible mechanisms, patterns, and processes of speciation, and establish new criteria to define the species that, by their relative abundance and short geologic range, have permitted adjustment of biostratigraphic markers for this period.

First record of Colpodidium caudatum (Ciliophora, Colpodidiidae) in Europe

The present study documents the discovery of the first European population of Colpodidium caudatum (Ciliophora, Colpodidiidae) in a water drain in a school playground in Manzanares (Ciudad Real, Spain). This species has been documented on every continent except Antarctica and Europe, until now. The ciliate was isolated from wet run-off soil collected from the water drain and was grown in semi-permanent cultures in the laboratory. The infraciliature of the ciliate was revealed using silver carbonate impregnation and cell measurements were taken from living and silver-impregnated specimens. A comparative analysis of published data from various populations of C. caudatum across the globe showed high intraspecific morphological variability in this species. To differentiate between species within the Colpodidium genus, a dichotomous key is presented. This investigation shows that C. caudatum is a ciliate that is found all over the world and is particularly associated with terrestrial habitats that are periodically flooded.

Skull morphology of bottlenose dolphins worldwide and patterns of adaptation between coastal and offshore environments

AbstractThe morphological differentiation between coastal and offshore ecotypes of bottlenose dolphins (genus Tursiops) has been researched since the 1960s, particularly in T. truncatus (Montagu, 1821), although most morphological studies have focused on localized populations. Therefore, it is unclear how patterns observed in these individual populations integrate within the global morphological variation. Here we carry out a meta‐analysis of global morphological variation between coastal and offshore ecotypes from 532 museum specimens, using both linear measurements (LM; 282 specimens), and shape data using geometric morphometrics (GM; 290 specimens). Together these analyses show consistent differentiation in skull morphology between coastal and offshore ecotypes, and provide a detailed description of variation patterns within each ecotype. These patterns show high individual morphological variation in the coastal ecotype between locations, while the offshore ecotype appears morphologically more uniform across the areas sampled. Overall, most skull shape variation can be described by features noticeable dorsally in the structures of the rostrum, whereas more limited change was found in ventral traits. Our results suggest that individual coastal populations may vary according to local environmental conditions, while those corresponding to the offshore ecotype appear to share similar morphological characteristics that might increase fitness in offshore habitats.

Quantifying the ability of imaging sonar to identify fish species at a subtropical artificial reef

Abstract Imaging sonars (ISs) are high-frequency acoustic devices that are increasingly being used to study fish in marine and freshwater habitats. Acoustic devices are limited in quantifying species richness, and previous attempts to identify fish species using IS have mostly focused on assemblages of low species richness or high morphological diversity. This study aimed to determine the ability of IS for identifying fish species at a subtropical artificial reef off Perth, Western Australia. Several fish traits that could be defined using IS were identified and described for all fish species observed with simultaneous optical footage. These traits were used to create a clustering algorithm to infer the species identity of IS detections of the five most abundant species at the reef. The identities of all fish from two species (Chromis westaustralis and Neatypus obliquus) were inferred with 100% success, though no individuals from the remaining three species (Seriola dumerili, Coris auricularis, and Pempheris klunzingeri) were correctly identified. An alternative clustering-based approach to categorising fish detected by IS independent of taxonomic inference was also implemented. Overall, this study demonstrates that IS can identify reef fish with variable success, and proposes an alternative method for describing fish assemblages irrespective of species identity.