Taxonomic Distinctness Research Articles

Continuous warming shifts the community pattern of periphytic protozoan fauna in marine environments

Protozoan fauna is playing an important role in the functioning of microbial food webs by transferring the flux of material and energy from low to high tropic levels in marine ecosystems. To assess effects of elevated temperature on the marine ecosystem, periphytic protozoan communities were used as the test microbial fauna, and were incubated in a temperature-controlled circulation system in a successive temperature gradient of 22 (control), 25, 28, 31 and 34 °C. The results showed that: (1) the test microbial fauna was shifted in both species composition and community structure; (2) the average taxonomic distinctness represented a clear decreasing trend, (3) while the variation in taxonomic distinctness significantly increased with increase of water temperature; and (4) the community pattern was significantly departed from an expectation when temperature increased by 12 °C. These results suggested that Protozoa may be used as a useful bioindicator of global warming in marine ecosystems.

Stream fish assemblages in the Eastern Amazon: the role of small tetras (Characidae) in alpha diversity and taxonomic structure

Abstract Wallacean shortfalls in knowledge about biodiversity, especially in the Amazon biome, can only be addressed by increasing sampling efforts in focal areas. The objective of this study was to describe the fish fauna of streams associated with four protected areas in the Eastern Amazon. These areas include the Tapajós (Parque Nacional da Amazônia, Parque Nacional do Jamanxim) and Trombetas drainages (Floresta Nacional Saracá-Taquera), and Tapajós/Xingu interfluve (Reserva Biológica Nascentes da Serra do Cachimbo), state of Pará, Brazil. In the 99 stream reaches surveyed, 176 fish species were recorded. Almost a third of the species and specimens belong to the Characidae family, predominantly represented by small tetras (known as piabasor lambaris). One threatened species (Harttia dissidens) was registered. Of the total richness, 24 species were singletons and associated with specific habitats. The highest taxonomic distinctness was observed for Floresta Nacional Saracá-Taquera, while streams within the Parque Nacional da Amazônia exhibited the greatest taxonomic distinctness variation. Compared to existing records in scientific collections covering stream fish fauna in watersheds of up to 4,300 hectares in Pará, our study added the record of eight other genera and identified relevant areas for additional surveys.

Redescription of Rhacophorus tuberculatus (Anderson, 1871) and the validity of Rhacophorus verrucopus Huang, 1983

Rhacophorus tuberculatus and Rhacophorus verrucopus are two morphologically similar species described in 1871 and 1983 respectively. Their taxonomic distinctiveness has been questioned in the past. In the current study, we encountered frogs that we confer to R. tuberculatus based on morphological similarity to a syntype of this species. We redescribe the species based on a re-examination of a syntype, which is designated as a lectotype here, and additional specimens from Garo hills of Meghalaya. We also present molecular data, natural history notes, and report a range extension of this species. Molecular phylogenetic analysis based on the 16S rRNA fragment revealed minimal genetic divergences (0.20–1.74% uncorrected p-distance) between specimens identified as either R. tuberculatus or R. verrucopus from different locations. On the basis of molecular data and morphological characteristics, we conclude that R. verrucopus is a junior synonym of R. tuberculatus.

Reconnoitre on ichthyofauna of Mahanadi River of India: shifting diversity down the river continuum and linking ecological traits with patterns in biodiversity.

Anthropogenic alterations have paramount impacts on the alpha and beta diversity of aquatic resources, and fishes are predominantly susceptible to such impacts. Mahanadi River, one of the major peninsular rivers of India, has abundant fish resources, which play a significant role in supporting the fishers' livelihoods. The exploratory study in the river conducted for three consecutive years recorded 148 species under 53 families. Cyprinids dominated the fish diversity with 41 species, followed by Bagrids (9) and Sciaenids (7). One hundred-one species under 29 families were reported from the freshwater stretch. With a total of 111 species reported under 48 families, the estuarine and tidal freshwater stretch was more speciose, due to marine migrant species which advent the estuarine and tidal freshwaters stretch for breeding and feeding purposes. Tikarpara, a conserved site within a sanctuary, was the most species-diverse as well as a species-even site. The study also recorded the extension of the distributional range of 3 fish species and also 4 exotic species from the river. The seasonal variations in diversity indicated that the deviations were not prominent in freshwater sites, whereas in tidal brackish water sites, species richness was relatively higher in post-monsoon, and species evenness was higher during monsoon. Taxonomic distinctness test showed that the average taxonomic distinctness was high for tidal estuarine locations as they harbour taxonomically distant fishes. The hierarchical clustering of sites showed the inordinate effect of river gradient and fragmentation on the fish community structure. Analyzing the key drivers of the assemblage structure of the entire river, salinity was the major deterministic factor, and within the freshwater stretch, the major influences were depth, transparency, and specific conductivity. The study concluded that, despite all of its ecological stresses, Mahanadi still supports rich fish diversity, yet there is a notable shift in the fish community structure. There is a need for integrating molecular and morphological tools for the taxonomic revision of many genera and species for proper in situ and ex situ conservation measures and to formulate future biodiversity management plans addressing to reduce the impacts of the ecological threats.

Responses of Different Plant Taxonomic Groups to Complex Environmental Factors in Peri-Urban Wetlands

Wetland plants are essential for ecosystem functions. However, wetland plants in peri-urban areas have been affected by increased human interference. Hence, analyzing the drivers of plant diversity could be extremely useful for biodiversity conservation. The main objective was to investigate the response of plant diversity in wetlands (e.g., plant richness, plant abundance, and taxonomic distinctness) to the environment in peri-urban areas. The results show that the wetland area is the most important factor influencing plant diversity in peri-urban areas. Plant richness and abundance decreased significantly with a decreasing wetland area. The cultivated land decreased the abundance of native plants and indirectly promoted native plant growth and spread by increasing the total organic carbon content of the water. Forest encroachment on wetlands significantly reduced native plant abundance. The effects of soil pH, water body pH, soil organic matter, and slope on introduced species showed opposite trends to those on native plants. Introduced plants were significantly more adapted to the land use around the wetland than native plants. The green land and forest areas promoted the spread of introduced plants. Introduced plants were significantly less adapted to the physicochemical properties of the soil and water than native species. Humans, through agricultural cultivation, have caused introduced plants in cultivated lands to escape to wetlands, resulting in an increase in introduced species. The riparian zone length showed opposite effects for aquatic and terrestrial plants. Pollution from urbanization and agriculture both positively and negatively affects aquatic plants. The response of aquatic plants to nutrients in the water was better than their response to soil nutrients and the response of terrestrial plants to soil nutrients. Terrestrial plants can better withstand pollution from urbanization and agricultural activities, as well as the erosion of wetlands from forested and cultivated lands.

Assessing the Seasonal and Spatial Dynamics of Zooplankton through DNA Metabarcoding in a Temperate Estuary.

Zooplankton are key components of estuarine trophic networks. However, routine monitoring is hindered by the difficulty of morphology-based identification. DNA-based methods allow us to circumvent some of these hurdles, providing precise species identifications regardless of the taxonomic expertise of the investigator or the developmental stage of the specimens. However, the process is dependent on the completeness of the reference libraries. In this study, we sought to evaluate the potential of DNA metabarcoding to assess the seasonal (summer, autumn, and early spring) and spatial dynamics of zooplankton (four locations spanning ca. 6 km) in the Lima estuary (NW Portugal). Two genetic markers were used: the cytochrome c oxidase subunit I and the V4 hypervariable region of the ribosomal 18S rRNA genes. Overall, 327 species were recovered, and both markers displayed minute overlap (7% were detected with both markers). Species richness, composition, and taxonomic distinctness were majorly influenced by the season, with a declining tendency from summer (highest number of exclusive species, n = 74) to spring. Second to season, the taxa composition was influenced by spatial variation where the most downstream site displayed the highest number of exclusive species, n = 53. A total of 16 non-indigenous species were detected using metabarcoding, but only one (Austrominus modestus) has been documented out in the estuary. In conclusion, both the seasonal and spatial gradients influenced the recovered richness, composition, and taxonomic distinctness, confirming the great aptitude of DNA metabarcoding for providing higher density monitoring and shedding new light on the composition and dynamics of complex zooplankton communities.

A new species of Ochthebius (Cobalius) (Coleoptera: Hydraenidae: Ochthebiinae) inhabiting marine rockpools of NW Sicily

Here we describe a new species of Ochthebius (Cobalius) from marine rockpools of NW Sicily: O. (C.) senczuki sp. n. This species was first discovered on the basis of molecular evidence, but its taxonomic distinction has been subsequently supported by morphological characters. Ochthebius (C.) senczuki sp. n. shows a clear genetic diversity from the known related species, with an average COI p distance ranging from 5.6% to 10.7%; it exhibits only small morphological differences, mostly limited to dorsal punctation, pronotal and elytral outer edge, and (in males) to the mobile part of the median lobe of the aedeagus. The origin of O. (C.) senczuki sp. n. is estimated to lie in the Late Miocene (~9 Mya); the ancestors of this taxon probably remained isolated from populations of the related taxa of the Ochthebius (Cobalius) subinteger and O. (Cobalius) adriaticus complexes during cycles of regressive and transgressive marine phases that occurred in the SW Mediterranean during Late Miocene and Pliocene. The detailed state of the art of members of the O. (Cobalius) adriaticus complex throughout the Central and Eastern Mediterranean rocky coastal areas is also preliminarily discussed. http://zoobank.org/urn:lsid:zoobank.org:pub:CBFA5063-2FBE-488B-8497-E5DA7DCA9361

Macroinvertebrate Spatial Diversity Patterns of Shore Habitats in Italian High-Altitude Natural and Permanent Lakes and Ponds

A comparative analysis of environmental conditions between Alpine and Apennine lakes/ponds which represent different faces of European mountain regions was conducted. The data set was created on the basis of previous works carried out by national and international institutions including biological, physical–chemical, geographic, and precipitation data from 27 lakes/ponds placed at altitudes ranging from 2334 ± 294 m a.s.l. (in the Alps) and 1541 ± 154 m a.s.l. (in the Apennines), with mean maximum depths of about 5.5 ± 4.6 m. A specific focus was dedicated to chironomids as outstanding sentinels for local and global changes in habitat conditions. Species richness and Taxonomic Distinctness Indices were applied to lakes/ponds macroinvertebrates to highlight differences in the biodiversity of the two areas. Subsequently, associations between descriptors of the mountain region climate, lithology, water chemistry, lake morphology, geography, macroinvertebrate assemblage richness, and distinctness were examined through Principal Component Analysis, Analysis of Variance, and Non-metric Multi-dimensional Scaling. Results showed strong positive correlations between mean annual precipitation and temperature with lake macroinvertebrate biodiversity as a whole and with chironomid in particular. Thus, these shore habitats face a threat under climate change conditions (impacting thermal and precipitation regimes). These results are also central in showing that even small ecosystems are important sources of biodiversity for the lower altitudes, stressing the urgency of including them within targeted monitoring and action plans to preserve their peculiar habitat, flora, and fauna.

Study on the taxonomic diversity of fish in the East China Sea hairtail national aquatic germplasm resources conservation zone

The species composition and taxonomic diversity of fish in the East China Sea hairtail national aquatic germplasm resources conservation zone (EHCZ) were analyzed by average taxonomic distinctness (Δ+) and variation in taxonomic distinctness (Λ+) based on the fishery resource survey from 2009 to 2022. It was found that there are 169 species of fish that are collected in the EHCZ, belonging to 26 orders, 73 families, and 131 genera. The Δ+ of EHCZ was about 65.5 and Λ+ was about 40.2. The Δ+ has exhibited a slightly down trend over the decade, which implies a slight decrease in fish diversity. The Δ+ was highest in spring, possibly due to fish migration for spawning. Most of the Δ+ of a year fall within the 95% confidence funnel for Δ+ values and all Λ+ of a year fall within the 95% confidence funnel for Λ+ values. The indices were relatively stable and close to the expected value. Moreover, we recommend optimizing the protection period, improving fishing gear and methods, reducing bycatch and decreasing the number of fishing vessels and vessel power to restore the fish diversity.

An annotated checklist of the Amphipoda (Crustacea) of Kuwait, north-western Arabian Gulf

Kuwait’s intertidal and subtidal habitats were surveyed from 2013 to 2016 for amphipods, and earlier records from Kuwait and the rest of the Gulf were compared to provide the first annotated checklist of Amphipoda in Kuwait. A total of 82 sites in mainland and islands were surveyed including intertidal and subtidal zones. The resulting data identified 86 amphipod taxa belonging to 54 genera, 32 families and 3 suborders, including 20 new records to science that are currently being described. A total of 46 amphipod species, 34 genera and 19 families constituted new regional records either for Kuwait or the entire Gulf area. Information on local distribution, occurrence, and habitat are provided for each species. Within the tidal zonation, 50 species inhabited both the intertidal and subtidal areas, 19 were intertidal, 12 subtidal, and 3 species were found in the supratidal zone. Sandy and rocky shores supported the most diverse amphipod assemblages. A gradient of increasing amphipod species richness from north to south along Kuwait’s mainland coastline was revealed. The high level of regional endemism supported notable taxonomic distinction of the amphipod fauna of Kuwait from the other Gulf areas. Compositional dissimilarity among amphipod faunas increased with distance within a wide longitudinal gradient across the Gulf, Sea of Oman, and north-western Arabian Sea.

Molecular evidence and environmental niche evolution at the origin of the disjunct distribution in three mountain endemic Tephroseris (Asteraceae) of the Mediterranean basin

Studies on the origin and evolutionary history of closely related plants help to understand patterns of diversity of the mountain flora in addition to providing the basis for their identification. The genus Tephroseris includes three endemic taxa with small and disjoint distributions in the high mountains of the Iberian Peninsula and on the Maritime Alps. Tephroseris balbisiana is native to the Southwestern Alps, Tephroseris elodes to Sierra Nevada, and Tephroseris coincyi to Sierra de Gredos. These taxa have been treated under different combinations of species or subspecies due to limited morphological differentiation, but comprehensive studies have not been published so far. By combining information from phylogeny, molecular dating and genome size, we demonstrated the taxonomic distinctiveness between T. balbisiana and the two Iberian taxa. Although the lack of variability in plastid DNA hampered the precise estimation of the diversification events, some of the recovered patterns suggested a recent divergence of T. balbisiana, T. elodes and T. coincyi dating back to the Pleistocene (0.5–2.8 Mya). However, niche modeling supported a geographical overlap between the three taxa during the Last Glacial Maximum (LGM). Moreover, the fragmentation of their ancient larger distribution range, particularly in the lower elevations of the Iberian Peninsula, and migration to glacial refuges in the south-western Alps, provide the most plausible explanations for the current disjoint distribution within the Mediterranean mountains. Furthermore, based on the evidence we gathered, we inferred that the alpine T. balbisiana, as well as the Iberian taxa, should be considered as three distinct subspecies.

Diversity and Distribution of the Benthic Foraminifera on the Brunei Shelf (Northwest Borneo): Effect of Seawater Depth

The marine benthic diversity of the Palawan/North Borneo ecoregion is poorly known, despite its implied unique high species richness within the Coral Triangle. The present study investigated the diversity and distribution of benthic foraminifera on the Brunei shelf. The objectives were to determine the species composition of sediment samples collected from 11 sites, extending ~70 km from the Brunei coastline and along a depth gradient of 10–200 m. We retrieved a total of 99 species, belonging to 31 families and 56 genera, out of which 52 species represented new records for Brunei and probably the ecoregion. Using presence/absence data, analyses were also performed to compare species diversity patterns (species richness, occupancy, taxonomic distinctness) and species assemblage similarity across the sites. For further insight into the relationship between distribution and depth-associated environmental conditions, we undertook stable isotope analyses of selected species of Rotaliida, Miliolida, and Lagenida. Oxygen isotope values were positively correlated with depth and species distribution, confirming cooler temperatures at greater depth. The carbon isotope data revealed species differences relating to habitat and food source specificity and a biomineralization effect. Close to one-third of the species were recorded from single sites, and species richness and taxonomic distinctness increased with depth and were greatest at the second deepest site (144 m). Together, these findings suggest data underrepresentation of diversity, habitat disturbance in shallower water, and species specialization (adaptation) in deeper water. Importantly, assemblage similarity suggests the occurrence of at least three marine biotopes on the Brunei shelf (10–40 m, 40–150 m, and >150 m). This study contributes significantly to our understanding of the local and regional patterns of foraminiferal diversity and distribution.

Hares from the Late Pleistocene of Ukraine: a phylogenetic analysis and the status of Lepus tanaiticus (Mammalia, Lagomorpha)

AbstractHares (genus Lepus) are widely distributed in Europe, and they are adapted to various types of habitats. Many species are known to hybridise, and previous molecular genetic studies have revealed recurrent introgressions between species at all stages of the genus’s radiation. The Don hare (Lepus tanaiticus) was described from the Late Pleistocene of the Southern Urals and subsequently reported from coeval deposits of various regions of northern Eurasia. It is morphologically close to the mountain hare (Lepus timidus) and recent studies of mitochondrial DNA questioned its status as an independent species. Here we compare cytochrome b and control-region sequences of mtDNA of arctic Lepus, including, for the first time, eight specimens from Late Pleistocene localities of Ukraine, in order to analyse the phylogenetic relationships between representatives of different taxa. The phylogenetic tree and haplotype network analyses do not support the taxonomic distinctness of the Don hare, and only specimens of Lepus arcticus and Lepus othus form monophyletic groups based on the control-region sequences. Instead, L. tanaiticus are scattered among specimens of L. timidus. The obtained results support the hypothesis that the Don hare is an ancient morphotype of L. timidus, and its distinctive morphological traits are the result of increased geographical variation of the latter due to range expansion and adaptation to the specific conditions of the periglacial biome, similarly to other Late Pleistocene small-mammal species.

Species diversity, trophic structure, and taxonomic distinctness of molluscan assemblages associated with Sargassum beds in a historically impacted bay

AbstractAnthropogenic impacts on coastal habitats can result in alterations of diversity parameters in marine invertebrate assemblages. Macroalgae beds are highly susceptible to human‐induced disturbances, supporting a great diversity of molluscan species and being ecologically important for coastal ecosystems. This study investigates the diversity alterations on Sargassum‐associated molluscan assemblages from areas with different distances from a main source of pollution within a historically impacted bay in Brazil. In general, sites closer to the pollution source presented lower species diversity, trophic diversity, and taxonomic relatedness among species. Beta diversity among assemblages was highly correlated with environmental differentiations among localities due to heavy metal concentrations in algal tissue. Bittiolum varium was the dominant species and was mainly responsible for differences in community parameters. Several trophic groups were well‐represented in Sargassum‐associated molluscan fauna, but assemblages were mostly dominated by micrograzers. A seasonal trend was observed in diversity alterations, with lower diversity during warm season at most sites except Santa Rita, possibly because it is the site less affected by human impacts. The importance of other environmental variables, such as hydrodynamism, for molluscan composition is also discussed. Our results highlight the potential of Sargassum‐associated molluscan assemblages for the study of impacted areas and reinforce the importance of using multiple community metrics to understand the biodiversity patterns of marine invertebrates under anthropogenic impacts.

Molecular and morphological studies reveal a new species of Panaeolus (Agaricales, Basidiomycota) from Punjab, Pakistan

Panaeolus punjabensis M. Asif, Q. Firdous, A. Izhar, Niazi & Khalid sp. nov. was collected from three different localities (Bahawalnagar, Kasur, and Lahore) in Punjab, Pakistan. Morphological observations and phylogenetic analyses based on nuclear encoded internal transcribed spacers (ITS1-5.8S-ITS2 = ITS) and D1/D2 domain of large subunit (28S) rDNA confirmed the taxonomic distinctness of this species. The new species is potentially hallucinogenic and characterized by a parabolic pileus with a light brown center, broadly fusiform basidiospores, presence of cheilocystidia, pileocystidia, and caulocystidia, and absence of pleurocystidia and clamp connections. The DNA sequences of the species clustered together in a well-supported distinct clade. We present a detailed description, photographs, and line drawings, and elucidate and discuss the phylogenetic position of the new species. Morphological comparisons with phylogenetically and morphologically allied species are discussed.

Morphometric analysis confirms the presence of the Plains-wanderer (Aves: Pedionomus torquatus) in fossil deposits at Naracoorte Caves, South Australia

ABSTRACT The Plains-wanderer (Pedionomidae: Pedionomus torquatus) is a species of Australian shorebird that exclusively inhabits open grasslands. The reported presence of this species in the fossil deposits of Naracoorte Caves suggests that it once inhabited a wooded environment. It was therefore important to assess whether the fossils are indeed conspecific with P. torquatus before inferences on the past palaeoecological preferences of the species are made. This study reassessed the identity of fossils identified as P. torquatus using both qualitative observations and morphometric analyses to test for proportional differences of fossil specimens which might indicate taxonomic distinction. Measurements were collected from fossils attributed to Pedionomus from Blanche Cave (45–15 ka) and Victoria Fossil Cave (>400–220 ka), and compared with modern skeletal specimens through univariate and principal component analyses. Fossil elements were significantly larger than the modern specimens, although marked overlap was consistently observed, precluding unambiguous differentiation on size. No qualitative traits distinguishing the two groups could be identified. The Naracoorte fossil Pedionomus are therefore considered to represent a population of P. torquatus, wherein birds were slightly larger than extant ones. The Naracoorte deposits sampled a forest and woodland-dominated environment over the last 400,000 years, one which would be deemed unsuitable for modern Plains-wanderers, indicating that P. torquatus may have formerly occupied a much broader range of habitats than its present distribution suggests. It is inferred that the Plains-wanderer underwent a marked contraction in occupied habitat during the Holocene.

Composition and Long-Term Variation Characteristics of Coral Reef Fish Species in Yongle Atoll, Xisha Islands, China.

Yongle Atoll was the largest atoll in the Xisha Islands of the South China Sea, and it was a coral reef ecosystem with important ecological and economic values. In order to better protect and manage the coral reef fish resources in Yongle Atoll, we analyzed field survey data from artisanal fishery, catches, and underwater video from 2020 to 2022 and combined historical research to explore the changes in fish species composition and community structure in Yongle Atoll over the past 50 years. The results showed that a total of 336 species of fish were found on Yongle Atoll, belonging to 17 orders and 60 families. Among them, Perciformes had the most fish species with 259 species accounting for 77.08% of the total number of species. The number of fish species in the coral reef of Yongle Atoll was exponentially correlated with its corresponding maximum length and significantly decreases with its increase. The fish community structure of Yongle Atoll changed, and the proportion of large carnivorous fish decreased significantly, while the proportion of small-sized and medium-sized fish increased. At the same time, Yongle Atoll has 18 species of fish listed on the IUCN Red List, 15 of which are large fish. The average taxonomic distinctness (Delta+, Δ+) and the variation taxonomic distinctness (Lambda+, Λ+) in 2020-2022 were lower than the historical data, and the number of fish orders, families, and genera in Yongle Atoll has decreased significantly, which indicates that the current coral reef fish species in Yongle Atoll have closer relatives and higher fish species uniformity. In addition, the similarity of fish species in Yongle Atoll was relatively low at various time periods, further proving that the fish community structure has undergone significant variation. In general, due to multiple impacts, such as overfishing, fishing methods, environmental changes, and habitat degradation, the fish species composition of Yongle Atoll may have basically evolved from carnivorous to herbivorous, from large fish to small fish, and from complexity to simplicity, leaving Yongle Atoll in an unstable state. Therefore, we need to strengthen the continuous monitoring of the coral reef ecosystem in Yongle Atoll to achieve the protection and restoration of its ecological environment and fishery resources, as well as sustainable utilization and management.

Can tidal events shape the taxonomic breadth of periphytic protozoa in intertidal zone ecosystems?

To evaluate the influence of tidal events (tidal disruption) on the taxonomic breadth of periphytons in intertidal zone ecosystems, a 1-month baseline survey on protozoan periphyton fauna was studied at five sampling sites from the highest tideline to the lowest (sites A–E) in an intertidal zone of the Yellow Sea, northern China. Samples were collected using an artificial substratum (glass slides) in the sea water with the sediment taken at each sampling site after a 14-day exposure period. The protozoan fauna showed a significant variation in both taxonomic composition and taxonomic distinctness measures along five tidelines. Based on the pair-wised taxonomic distinctness measures (Δ+ and Λ+), the expectation test revealed an increasing departure of the periphyton samples from an expected taxonomic breadth from the highest to the lowest tideline. Therefore, it suggests that tidal events (tidal disruption) may significantly shape the taxonomic breadth of protozoan periphyton fauna in intertidal zones of marine ecosystems.

Intrageneric taxonomic distinction based on morphological variation in the macaque (Macaca) skeleton.

Taxonomic classification is important for understanding the natural world, yet current methods for species assessment often focus on craniodental morphology rather than the entire skeleton. Moreover, it is currently unknown how much variation could, or should, exist intragenerically. Here, we tested whether taxonomy can be accurately predicted based on patterns of morphological variation in macaques (H1 ) and whether postcranial bones reflect subgeneric macaque taxonomy similarly, or better, than the cranium (H2 ). Data included 3D scans of cranial and postcranial bones for eight macaque species (Macaca arctoides, Macaca fascicularis, Macaca fuscata, Macaca mulatta, Macaca nemestrina, Macaca nigra, Macaca radiata, and Macaca sylvanus). Fixed anatomical and semilandmarks were applied to scans of eight skeletal elements (crania = 45; mandible = 31; scapula = 66; humerus = 38; radius = 33; os coxa = 28; femur = 40; tibia = 40). For each skeletal element, regression analyses were performed to minimize the effects of sexual dimorphism. Between-groups principal components analysis was used to visualize the major patterns of among-species morphological variation, while the strength of correct taxon classification was measured with discriminant function analysis. Results suggested accepting the alternate hypothesis that different macaque species can be distinguished morphologically. Both cranial and many postcranial elements appeared to possess a taxonomic signal, and the limb bones-especially the upper limb-are reported to be more useful for taxonomic assessment than previously realized. Theoretically, certain behaviors and/or ecogeographical factors, as well as phylogeny, influenced skeletal morphology in macaques, likely contributing to taxonomic distinctions among different species.

Taxonomic Structure and Diversity of Benthic Diatoms (Bacillariophyta) in the Northern Shelf of the Black Sea

The key role of benthic diatoms in coastal ecosystems highlights the relevance of studying their biodiversity and developing integrated biodiversity conservation measures. Benthic diatom richness in the northern part of the Black Sea was estimated based on both published data and our own data. The checklist of benthic diatoms includes 1100 species and intraspecific taxa, 953 species, 149 genera, 61 families, 32 orders, and 3 classes of Bacillariophyta. More than 280 species and intraspecific taxa, as well as 8 genera new to the diatom flora of the Black Sea and 7 species new to science, were revealed. An interregional analysis of the diversity of benthic Bacillariophyta along the coasts of Bulgaria, Romania, and Crimea, as well as the northwestern and northeastern parts of the Black Sea shelf, was carried out using the Taxonomic Distinctness Indices (TaxDI). The lowest TaxDI value for Crimea was closest to the average value expected for the Black Sea diatom flora, indicating a large proportion of polyspecies branches in the taxocene structure, which resulted in the maximum species richness (species/genus = 7) and led to a decrease in the vertical evenness of hierarchical tree. On the contrary, the highest TaxDI value was detected off the Romanian coast, which was caused by the significant proportion of mono- and oligospecies branches and minimal species saturation in the taxocene structure (species/genus = 4). We also identified some species with a high taxonomic exclusivity rank. If these species disappear, the entire architectonics of the Black Sea hierarchical tree of Bacillariophyta may be significantly altered. Such region-specific species are given the highest protection priority since they have great importance for gene pool conservation.