Valid Taxon Research Articles

Revised anatomy, taxonomy and biostratigraphy of Notochampsa istedana Broom, 1904, a Lower Jurassic crocodyliform from the Clarens Formation (Stormberg Group), and its implications for early crocodyliform phylogeny

The early-branching crocodylomorph species Notochampsa istedana is known from a single South African specimen collected more than 100 years ago. This species is potentially important for understanding early crocodylomorph evolution, but it is of uncertain taxonomic status and its stratigraphic position is poorly constrained. Here we reinvestigate the anatomy, taxonomy, systematics and biostratigraphy of the holotype specimen, SAM-PK-4013. SAM-PK-4013 has a unique suite of features that distinguish it from the closely related taxa Orthosuchus and Protosuchus. These features include the length and shape of the dentary symphysis, the number and shape of dentary teeth, and the number of dorsal ribs with expanded intercostal ridges. Notochampsa is therefore a valid taxon, and our phylogenetic analysis recovers it as sister to Orthosuchus, in a monophyletic Notochampsidae. Notochampsa and Orthosuchus share a ventrally expanded squamosal flange and expanded intercostal ridges on the dorsal ribs. Notochampsidae is in turn sister to Protosuchidae, forming the monophyletic group Notochampsoidea. Fieldwork and stratigraphic revisions show definitively that SAM-PK-4013 is from the Clarens Formation, approximately ∼65 m above the Elliot contact, ageing Notochampsa to the Pliensbachian stage, a period of vertebrate body fossil scarcity. Thus, Notochampsa istedana is the youngest known occurrence of a crocodylomorph (and vertebrate body fossil) from the Karoo Basin of South Africa.

New and little-known digger wasps (Hymenoptera: Ampulicidae, Sphecidae, Crabronidae) from Russia.

New additions to the knowledge of digger wasps (Ampulicidae, Sphecidae, Crabronidae) in Russia are provided. Tachysphex loktionovi Mokrousov Proshchalykin, sp. nov. is described from Tyva Republic. Five species of digger wasps are reported from Russia for the first time: Hoplammophila clypeata (Mocsáry, 1883) (Sphecidae), Tachysphex desertorum F. Morawitz, 1894, T. mongolicus Kohl, 1898, Tachytes argenteus Gussakovskij, 1933, and Trypoxylon albipes F. Smith, 1856 (Crabronidae). Misidentified Tachysphex speciosissimus Morice, 1897 (=T. gussakovskii Pulawski, 1971) is excluded from the fauna of Russia. Hitherto unknown male of Tachysphex mongolicus Kohl, 1898, stat. resurr. is described and regarded as a valid taxon. New synonymy is proposed for T. mongolicus Kohl, 1898 = T. abditus Kohl, 1898, syn. nov. Diagnosis for male of Dolichurus haemorrhous A. Costa, 1886 is updated. New regional records for seven species are recorded. The known fauna of Russia currently numbers three families, 87 genera and 694 species of digger wasps. In addition Tachytes argenteus Gussakovskij, 1933 is reported for the first time from Uzbekistan and Cyprus, and Trypoxylon beaumonti Antropov, 1991 is newly recorded from Ukraine.

New anomalocaridids (Panarthropoda: Radiodonta) from the lower Cambrian Chengjiang Lagerstätte: Biostratigraphic and paleobiogeographic implications

Radiodonts are a morphologically and ecologically diverse clade of stem-group euarthropods that occupied numerous ecological niches in early animal ecosystems. Many Cambrian taxa are considered apex predators, primarily due to the possession of raptorial frontal appendage, though sweep and filter-feeding examples were also prevalent. Four major families have been distinguished including Anomalocarididae, whose elongate appendages consist of a series of podomeres bearing short endites. Studies of anomalocaridids have seen limited investigation in the Chengjiang Lagerstätte (Cambrian Stage 3) of China, despite the deposit being well-known for the diverse radiodont assemblage, and recently the putative anomalocaridid ‘Anomalocaris’ saron was reassigned to Tamisiocarididae. Here we present exceptionally preserved specimens of two new anomalocaridid taxa from Chengjiang. Lenisicaris lupata gen. et sp. nov. represents the first valid Chengjiang anomalocaridid taxon, characterized by bearing short endites lacking auxiliary spines on almost all its podomeres. A second taxon, Anomalocaris cf. canadensisWhiteaves, 1892, indicates a broad geographical range for this famous Burgess Shale species. With the help of this new information, we show that the family Anomalocarididae was widespread at low latitudes from Cambrian Stage 4 to the Guzhangian. The biogeographical patterns of anomalocaridids suggest a high dispersal capability in the larval form of anomalocaridids, and possible climatic control on their distribution. Furthermore, the known distribution of anomalocaridids in the well-documented soft-bodied biotas indicates that anomalocaridids were likely adapted to a broad spectrum of environments.

Linking environmental with biological data: Low sampling frequencies of chemical pollutants and nutrients in rivers reduce the reliability of model results

Linking environmental and biological data using ecological models can provide crucial knowledge about the effects of water quality parameters on freshwater ecosystems. However, a model can only be as reliable as its input data. Here, the influence of sampling frequency of temporal variable environmental input data on the reliability of model results when linked to biological data was investigated using Threshold Indicator Taxa Analysis (TITAN) and species sensitivity distributions (SSDs). Large-scale biological data from benthic macroinvertebrates and matching water quality data including four metals and four nutrients of up to 559 site-year combinations formed the initial data sets. To compare different sampling frequencies, the initial water quality data sets (n = 12 samples per year, set as reference) were subsampled (n = 10, 8, 6, 4, 2 and 1), annual mean values calculated and used as input data in the models. As expected, subsampling significantly reduced the reliability of the environmental input data across all eight substances. For TITAN, the use of environmental input data with a reduced reliability led to a considerable (1) loss of information because valid taxa were no longer identified, (2) gain of unreliable taxon-specific change points due to false positive taxa, and (3) bias in the change point estimation. In contrast, the reliability of the SSD results appeared to be much less reduced. However, closer examination of the SSD input data indicated that existing effects were masked by poor model performance. The results confirm that the sampling frequency of water quality data significantly influences the reliability of model results when linked with biological data. For studies limited to low sampling frequencies, the discussion provides recommendations on how to deal with low sampling frequencies of temporally variable water quality data when using them in TITAN, in SSDs, and in other ecological models.

Taxonomic Revision of Living Boring Bivalves Belonging to the Family Pholadidae Lamarck, 1809, (Bivalvia: Myida) from the Southwestern Atlantic.

Boring bivalves of the family Pholadidae Lamarck, 1809 living in Argentinean and Uruguayan waters are herein revised. The literature research revealed twelve nominal species of Pholadidae mentioned as living in the study area. Type material of all nominal taxa were examined when it was possible. Additional specimens from field works and malacological collections were studied, illustrated and re-described. Details of type localities, repositories, and distribution range are provided for each valid taxa. This work revealed the presence of five native and one introduced species belonging to Pholadidae in Argentinean and Uruguayan waters. Barnea (Anchomasa) lamellosa, Cyrtopleura (Scobinopholas) lanceolata, Pholas (Thovana) campechiensis and Martesia fragilis belonging to the Argentine biogeographical province; Netastoma darwinii from Magellan province; and Barnea (Anchomasa) truncata introduced in the Bahía Blanca estuary. Finally, morphological comparison with congeneric species distributed in American seas are provided.

REVISION OF THE DEVONIAN FENESTRATE BRYOZOAN GENERA Cyclopelta BORNEMANN, 1884 AND Pseudoisotrypa PRANTL, 1932, WITH DESCRIPTION OF A RARE FENESTRATE GROWTH HABIT

The fenestrate bryozoan genus Cyclopelta is common and locally abundant in Devonian rocks of central and western Europe. Cyclopelta is a junior homonym and is here renamed Bigeyina. The Bohemian genus Pseudoisotrypa, very closely related with Bigeyina and formerly interpreted as a junior synonym of the latter, is restored herein as a valid taxon. Revised diagnoses of both genera and their type species are provided. Also, an extremely rare variation on the conical growth habit is reported in Bigeyina and implies higher plasticity in this genus than usual in fenestrates. The presence of abundant Bigeyina zoaria with this rare growth habit in the well known outcrop of Arnao (Spain), emphasizes the need for the preservation of its paleontological heritage.

Lectotype designation for Orbitolinopsis flandrini Moullade, 1960 (Foraminifera): The missing piece of a taxonomic puzzle

Orbitolinopsis flandrini Moullade, 1960, was described from Lower Cretaceous Urgonian limestones of southeastern France without the designation of a holotype. It represents a valid taxon since the selection of a holotype is only obligatory for taxa established after 1999 (ICZN, 4th edition, article 72.3). Today the original description is considered to be a mixture of several taxa belonging to Orbitolinopsis Henson, 1948/Cribellopsis Arnaud-Vanneau, 1980 (transverse sections with cupules/septules in the central zone) and Drevennia Arnaud-Vanneau, 1980 (axial sections with an axial columella-like column). The short and in any case insufficient original description of O. flandrini, however, stressed the presence of a columellar-like central test as the main characteristic feature. In fact, the majority of the (sub)axial sections showing an axial column (lacking in Orbitolinopsis) are considered to belong to Drevennia (Family Pfenderinidae). Therefore, the new combination Drevennia flandrini (Moullade, 1960) is proposed and a lectotype herein designated from the original illustrations. Drevennia ecougensis, the type-species of the genus, is found to be a subjective junior synonym of the latter. New finds from Serbia and Spain extend the stratigraphic range of D. flandrini, from the upper Berriasian to the lowermost upper Aptian. The first occurrences of Drevennia, Dobrogelina Neagu, 1979, Pfenderina Henson, 1948, and Moulladella Bucur & Schlagintweit, 2018, in the upper Berriasian give evidence for an adaptive radiation of the Pfenderinidae during the time reported and from other, mostly complex larger benthic foraminifera (e.g., Orbitolinidae).

Skeletal Anatomy of Acaenasuchus Geoffreyi Long and Murry, 1995 (Archosauria: Pseudosuchia) and its Implications for the Origin of the Aetosaurian Carapace

ABSTRACT Acaenasuchus geoffreyi is a diminutive armored archosaur from the Upper Triassic Chinle Formation of northern Arizona, U.S.A., with uncertain evolutionary relationships and skeletal maturity. Known only from osteoderms, the taxon has been considered a valid taxon of aetosaur, juvenile specimens synonymous with the aetosaur Desmatosuchus spurensis, or a non-aetosaurian pseudosuchian archosaur. Here, we describe new fossils of Acaenasuchus geoffreyi that represent cranial, vertebral, and appendicular elements as well as previously unknown variations in the dorsal carapace and ventral shield. The skull bones are ornamented with the same anastomosing complex of ridges and grooves found on the paramedian and lateral osteoderms, and the appendicular skeleton resembles that of Revueltosaurus callenderi, Euscolosuchus olseni, aetosaurs, and other armored archosaurs such as erpetosuchids. Histology of osteoderms from the hypodigm of Acaenasuchus geoffreyi shows multiple growth lines, laminar tissue, and low vascularity, evidence that the individuals were close to skeletal maturity and not young juveniles. A revised phylogenetic analysis of early archosaurs recovers Acaenasuchus geoffreyi and Euscolosuchus olseni as sister taxa and members of a new clade that is the sister taxon of Aetosauria. This new phylogeny depicts a broader distribution of osteoderm character states previously thought to only occur in aetosaurs, demonstrating the danger of using only armor character states in aetosaur taxonomy and phylogeny. Acaenasuchus geoffreyi is also a good example of how new fossils can stabilize ‘wild card’ taxa in phylogenetic analyses and contributes to our understanding of the evolution of the aetosaur carapace.

The braincase of <em>Bissektipelta archibaldi</em> — new insights into endocranial osteology, vasculature, and paleoneurobiology of ankylosaurian dinosaurs

We describe in detail three braincases of the ankylosaur Bissektipelta archibaldi from the Late Cretaceous (Turonian) of Uzbekistan with the aid of computed tomography, segmentation, and 3D modeling. Bissektipelta archibaldi is confirmed as a valid taxon and attributed to Ankylosaurinae based on the results of a phylogenetic analysis. The topographic relationships between the elements forming the braincase are determined using a newly referred specimen with preserved sutures, which is an exceedingly rare condition for ankylosaurs. The mesethmoid appears to be a separate ossification in the newly referred specimen ZIN PH 281/16. We revise and discuss features of the neurocranial osteology in Ankylosauria and propose new diagnostic characters for a number of its subclades. We present a 3D model of the braincase vasculature of Bissektipelta and comment on vascular patterns of armored dinosaurs. A complex vascular network piercing the skull roof and the wall of the braincase is reported for ankylosaurs for the first time. We imply the presence of a lepidosaur-like dorsal head vein and the venous parietal sinus in the adductor cavity of Bissektipelta. We suggest that the presence of the dorsal head vein in dinosaurs is a plesiomorphic diapsid trait, and extant archosaur groups independently lost the vessel. A study of two complete endocranial casts of Bissektipelta allowed us to compare endocranial anatomy within Ankylosauria and infer an extremely developed sense of smell, a keen sense of hearing at lower frequencies (100–3000 Hz), and the presence of physiological mechanisms for precise temperature control of neurosensory tissues at least in derived ankylosaurids.

Taxonomic revision of Microdaiphron Pic, 1926 (Coleoptera: Cantharidae: Chauliognathinae)

The genus Microdaiphron Pic, 1926 is revised. Ten species are recognized as valid: Microdaiphron polemioides (Kirsch, 1889), M. implicitus (Erichson, 1847) comb. nov., M. pauloensis (Pic, 1926), M. peruvianus Pic, 1938, M. mendesensis (Pic, 1926), M. tapuruquara sp. nov., M. geodesicus sp. nov., M. batasitensis (Pic, 1926), M. guyanensis Constantin, 2016, and M. brevehumeralis Pic, 1938. Other 23 names within Microdaiphron are synonymized with the currently valid species, whilst Microdaiphron bicoloricornis Pic, 1947 is transferred to Malthesis Motschulsky, 1853. The taxonomic status of three primary homonyms is also discussed. Daiphron polemioides var. atripenne Pic, 1927 (=Microdaiphron implicitus comb. nov.) is the senior homonym of Daiphron atripenne Pic, 1934 and Daiphron atripenne var. bipartitum Pic, 1934. The later is synonymized and reinstated as a valid species under the name D. bipartitus Pic, 1934. Descriptions, distribution maps and illustrations of diagnostic features are presented for all valid taxa, including the photographs of primary types in all available names within Microdaiphron.

MAASTRICHTIAN LARGER BENTHIC FORAMINIFERA FROM THE ARABIAN PLATE SENSU LATO: NEW DATA FROM SOMALIA, TURKEY, AND IRAN

Larger benthic foraminifera from the upper Maastrichtian Auradu Formation of Somalia exhibit striking matches with the assemblages from the time-equivalent Tarbur Formation of Iran and other, but less well studied lithostratigraphic units in SE Turkey (e.g., Garzan Fm.). Some taxa, among also new ones, described from Somalia need taxonomic updates (revision, synonymy, re-instatement). Dukhania? cherchii Luger is considered a junior synonym of Acordiella? tarburensis Schlagintweit & Rashidi, and Pseudorbitolina schroederi Luger is re-instated and considered a valid taxon, different from the Campanian P. marthae Douvillé of the western Tethyan domain. The genus Cyclopsinella Galloway is reported for the first time from the upper Maastrichtian of Iran.

Invalidation of taxa within the silvery wooly monkey (Lagothrix lagothricha poeppigii, Atelidae, Primates)

The systematics of the Humboldt’s wooly monkeys (L. lagothricha; Atelidae) is essential to preserve this Neotropical primate species. Traditionally, four morphological subspecies have been described, which recently have been molecularly confirmed. However, no population genetics studies have been carried out throughout the geographical distribution of one of these subspecies, Lagothrix lagothricha poeppigii. For this reason, we analyzed nine mitochondrial genes of L. l. poeppigii mainly collected from the Ecuadorian and Peruvian Amazon in order to better understand the evolutionary history of this taxon. The mitochondrial genetic diversity levels (haplotype and nucleotide diversity) we estimated are likely the highest yet reported for L. lagothricha. Our results did not detect important genetic structure within L. l. poeppigii. Furthermore, our phylogenetic analyses did not detect any relevant molecular cluster in the area where Groves hypothesized the existence of L. poeppigii castelnaui. Therefore, based on these data, castelnaui is not a valid taxon from a molecular perspective. The most differentiated subpopulation within L. l. poeppigii was from Morona-Santiago province (Ecuador) and had a genetic distance of 0.8–1.2% relative to the other subpopulations studied. However, this genetic distance range is within the variability found within a population. We estimated the mitochondrial temporal diversification within L. l. poeppigii to have occurred during the Pleistocene, 1.8–1.2 million years ago. Similarly, all our analyses detected a strong Pleistocene female population expansion for this taxon. Diverse spatial genetic analyses, perhaps with the exception of Monmonier’s Algorithm, did not detect differentiated taxa within the area analyzed for L. l. poeppigii. These genetics results could be of importance to conservation efforts to preserve this taxon as one unit.

The enigma of Enaliosuchus, and a reassessment of the Lower Cretaceous fossil record of Metriorhynchidae

Enaliosuchus macrospondylus Koken, 1883 was one of the first thalattosuchian taxa from the Cretaceous to be described. The type series includes an atlas-axis complex, remnants of three post-axial cervical vertebrae, several dorsal vertebrae, a caudal vertebra, an incomplete femur and a fragmentary sacral rib from the upper Valanginian of northern Germany. Additionally, two isolated, non-thalattosuchian, tooth crowns from the uppermost Valanginian to lowermost Hauterivian of different localities in northern Germany were tentatively assigned to E. macrospondylus by Koken. The taxon was established for the distinctive the atlas-axis morphology, in particular the apparent lack of an axis parapophysis. Enaliosuchus macrospondylus has been considered a valid taxon in recent studies, based upon a largely complete metriorhynchid specimen from the Valanginian of France that had been referred to this taxon, an assignment that has never been questioned. Here we provide a detailed re-description of the E. macrospondylus holotype specimen and determine whether it is diagnostic, and if a referral of the French specimen to E. macrospondylus is justified. We also discuss whether E. macrospondylus and another metriorhynchid specimen from the Valanginian of northern Germany, described as Enaliosuchus schroederi, are conspecific. Finally, we provide an overview of the current knowledge of metriorhynchid diversity during the Cretaceous.

On the genus Crossaster (Echinodermata: Asteroidea) and its distribution.

Several starfish (Echinodermata, Asteroidea) are keystone species of marine ecosystems, but some of the species are difficult to identify using morphological criteria only. The common sunstar, Crossaster papposus (Linnaeus, 1767), is a conspicuous species with a wide circumboreal distribution. In 1900, a closely similar species, C. squamatus (Döderlein, 1900) was described from the NE Atlantic Ocean, but subsequent authors have differed in their views on whether this is a valid taxon or rather an ecotype associated with temperature variations. We assessed the differentiating morphological characters of specimens from Norwegian and Greenland waters identified as C. papposus and C. squamatus and compared their distributions in the NE Atlantic as inferred from research cruises. The field data show that C. papposus is found mainly in temperate and shallow waters, whereas C. squamatus resides on the shelf-break in colder, mixed water masses. Intraspecific diversity and interspecific genetic differentiation of the two putative species, and their phylogenetic relationships to several Crossaster congeners worldwide, were explored using mitochondrial and nuclear DNA sequences. The molecular evidence suggests that C. papposus is the more diverse and geographically structured taxon, in line with its wide distribution. C. papposus and C. squamatus are closely related, yet clearly distinct taxa, while C. papposus and C. multispinus H.L. Clark, 1916, the latter from the South Pacific Ocean, are closely related, possibly sister taxa.

Delimiting the snapping shrimp Alpheus lobidens De Haan, 1849 (Caridea: Alpheidae) based on morphological and molecular data.

Our aim was to delimit the taxonomic status of the snapping shrimp Alpheus lobidens De Haan, 1849, based on morphological and molecular analyses of the topotype material from Nagasaki (Japan). We provide a redescription, detailed illustrations, and molecular data. Through comparisons with close-related species, we also tested the taxonomic status of A. inopinatus Holthuis Gottlieb, 1958 and A. buckupi Almeida, Terossi, Araújo-Silva Mantelatto, 2013. We examined 74 specimens previously identified as A. lobidens, 84 specimens of A. buckupi, and 30 of A. inopinatus. The morphological analysis was based on the examination of 68 characters. The molecular analysis included mitochondrial gene sequences (16S) of 18 individuals: six A. lobidens, three A. buckupi, one A. inopinatus, and eight individuals of other species of Alpheidae. The morphological analysis revealed that A. lobidens sensu stricto is consistently distinct of A. lobidens sensu lato, A. inopinatus and A. buckupi. The genetic analyzes (Bayesian Inference and p-distance) corroborated the morphological results and showed a clear separation between them. The highest values of genetic divergence (p-distance) (19%) were observed between A. lobidens sensu stricto and A. buckupi, and between A. lobidens sensu stricto and A. lobidens sensu lato from Australia (Northern Territory). The lowest divergence (12%) occurred between A. lobidens sensu stricto and A. lobidens sensu lato from Marshall Islands. Based on our results, the occurrence of A. lobidens sensu stricto is currently restricted to the type locality in Japan, and A. inopinatus and A. buckupi are valid taxa. Delimiting A. lobidens sensu stricto is relevant since the name A. lobidens has been applied to cryptic species, resulting in a high unclear taxonomic state.

Cymothales annisancti Navás, 1926 is a valid species (Neuroptera: Myrmeleontidae)

Cymothales annisancti Navas, 1926, formerly kept as a synonym. On the basis of a Cymothales specimen from Republic of Guinea we concluded, it is conspecific with the type of Cymothales annisancti Navas, 1926. The valid taxon is compared to Cymothales liberiensis van der Weele, 1904. With 8 figures.

Molecular phylogeny of Eupodidae reveals that the family Cocceupodidae (Actinotrichida; Eupodoidea) and its genus Filieupodes are valid taxa.

The family Eupodidae is one of eight families belonging to the superfamily Eupodoidea. Although the Eupodidae are very common mites, they are still poorly investigated and the systematic parameters of the family are vague with unclear intrafamilial relationships between its genera. According to the hypothesis of Jesionowska (Genus 21(4):637-658, 2010), the eupodid genera Cocceupodes, Linopodes and her new genus Filieupodes should be transferred from the Eupodidae to a separate family named Cocceupodidae. The opposite hypothesis of Khaustov (ZooKeys 422:11-22, 2014) considers the family Cocceupodidae an artificial taxon and the genus Filieupodes a junior synonym of Cocceupodes and assignes the family Eupodidae its primary definition. Here, we present the first molecular reconstruction of phylogenetic relationships within the Eupodidae. We test the taxonomic status of the Eupodidae and refer to the previous hypotheses based on morphological data. According to the reconstructed phylogram based on nuclear (18S + 28S rDNA) and mitochondrial (COI) sequences as well as morphological characters tracing this analysis, we have concluded that: (1) the genera Linopodes, Filieupodes and Cocceupodes are a separate monophyletic lineage of familial rank and the sister group of Eupodidae s.s., and (2) the genus Filieupodes should be considered a separate genus being a sister group of the Linopodes-Cocceupodes clade.

Morphological and molecular characterization of Acrobeloides saeedi Siddiqi, De Ley and Khan, 1992 (Rhabditida, Cephalobidae) from India and comments on its status.

Two cultured populations of Acrobeloides saeedi are described from India. Morphologically and morphometrically this material agrees with other species of the Maximus-group (A. bodenheimeri, A. longiuterus, and A. maximus), especially with A. longiuterus. However, molecular studies based on 18 S, 28 S and ITS rDNA confirmed the Indian material is well differentiated from all of these species. According to this, A. saeedi is considered a valid taxon distinguished mainly from A. bodenheimeri by having dextral female reproductive system (vs sinistral), from A. longiuterus by having larger females (1.03-1.57 vs 0.57-0.88 mm) and from A. maximus by having seta-like labial processes (vs absent) and males as frequent as females (vs males very infrequent). Molecular and phylogenetic studies revealed the present specimens to be conspecific to undescribed Acrobeloides sp. population from Iran, and hence, both regarded to be conspecific to each other. In addition, other similar species are revised: Acrobeloides ishraqi is considered new junior synonym of A. saeedi, Acrobeloides mushtaqi is considered new junior synonym of A. bodenheimeri, while Acrobeloides gossypia is also considered junior synonym of A. saeedi.

Genetic variation and admixture of red-eared sliders (Trachemys scripta elegans) in the USA

The most ubiquitous, abundant, and invasive turtle on Earth, Trachemys scripta elegans (TSE, “red-eared slider”), is one of four taxa in a clade that is native to the USA and adjacent Mexico (three subspecies of Trachemys scripta plus Trachemys gaigeae). The present range-wide study of this clade is based on 173 known-locality mtDNA sequences combined with ddRAD libraries for 43 samples emphasizing the western part of the range of TSE, its contact with that of T. gaigeae, and anthropogenic hybrids between TSE and T. s. scripta. The data presented here are the first to sample the TSE × T. s. scripta intergrade zone or TSE × T. s. scripta crosses from introduced turtles. In the western part of its range (New Mexico and Texas), most samples of TSE from the Pecos River have mtDNA haplotypes matching T. gaigeae. Structure analysis of SNPs from the ddRAD show evidence of genetic admixture between T. gaigeae and TSE in all included samples from the Rio Grande and Pecos River. These populations also exhibit T. gaigeae-like head stripes, i.e., a postorbital marking that does not reach the eye. The genetic and morphological data are thereby reconciled, as both suggest that these TSE are intergrades. We recommend that these populations continue to be considered TSE, despite the admixture with T. gaigeae. In the Eastern United States, some samples of the morphologically intermediate subspecies T. s. troostii are not genetically distinct from TSE and some samples share morphological characters and genetic affinities with T. s. scripta. Based on these observations we conclude that the taxon T. s. troostii represents intergrades between TSE and T. s. scripta and should not be considered a valid taxon. Near the already established part of the intergrade zone between TSE and T. s. scripta, TSE mtDNA haplotypes have naturally introgressed into typical-looking samples of T. s. scripta in Georgia. Hybrids between introduced TSE and T. s. scripta are also confirmed deeper within the natural range of T. s. scripta in South Carolina and Virginia. Given the examples of feral hybrids deep within its range shown here and elsewhere, the threat of genetic pollution of T. s. scripta by feral TSE is established.

The first record of redfieldiiform fish (Actinopterygii) from the Upper Triassic of Korea: Implications for paleobiology and paleobiogeography of Redfieldiiformes

A new genus and species of redfieldiiform fish, Hiascoactinus boryeongensis gen. et sp. nov., is described based on a nearly complete specimen from the Upper Triassic Amisan Formation of South Korea. Hiascoactinus is distinguished from other redfieldiiforms by having a barely ornamented dermal skull surface except for the snout region, two heteromorphic suborbitals arranged vertically behind the postorbital, a pistol-shaped suprascapular, and dorsal and anal fins with divided fin membranes between rays. The morphological features of the snout region and dorsal and anal fins of Hiascoactinus provide important clues to understand its feeding and swimming behavior. All previously proposed Asian redfieldiiform fossils are inaccurately classified, and consequently, Hiascoactinus is regarded as the only valid redfieldiiform taxon in Asia. Hiascoactinus is assigned to the basal group of redfieldiiforms primarily based on the presence of an antopercle. The basal phylogenetic position of Hiascoactinus indicates that basal redfieldiiforms dispersed from the southern Gondwanaland to the easternmost Laurasia through the terrestrial water system, and these two landmasses were connected during the Late Triassic.