Adán Pérez-García

A New Turtle Species of Brodiechelys from the Early Cretaceous of Spain: Systematic and Palaeobiogeographic Implications

Brodiechelys brodiei is an Early Cretaceous turtle from Great Britain, the only species of the genus. This taxon has been shown in recent phylogenies to be closely related to Xinjiangchelyidae and therefore could be the only representative of this group in Europe. Here, we present several specimens from the Early Cretaceous Maestrazgo Basin, in the Iberian Range of Spain attributed to the British genus, and to a new species, Brodiechelys royoi. This discovery shows that, as previously observed with terrestrial turtles, some freshwater turtle taxa had a wide European distribution during the Early Cretaceous, being present in both Britain and the Iberian Peninsula. This study sheds new light on the phylogenetic position of this enigmatic genus, supporting its attribution to Xinjiangchelyidae, a clade whose presence has been previously confirmed exclusively from the Middle Jurassic to Early Cretaceous of Asia. We propose that another recently identified taxon from the Iberian Peninsula (i.e., Larachelus morla) is also a member of this clade. Recent studies have identified several continental taxa of the clade that included the members of “Macrobaenidae” and “Sinemydidae” in Europe. This study provides new evidence of close relationships between the Early Cretaceous turtle faunas from Europe and Asia.

A New Freshwater Basal Eucryptodiran Turtle from the Early Cretaceous of Spain

A freshwater turtle from the lithographic limestone of Las Hoyas (Barremian of Cuenca, Spain) is described as a new genus and species of Eucryptodira, Hoyasemys jimenezi. The holotype consists of the skull, lower jaw, carapace, plastron, vertebral column, pectoral and pelvic girdle remains, and fore- and hindlimbs. Hoyasemys jimenezi gen. et sp. nov. is characterized by three pairs of blind oblique depressions on the ventral surface of the basisphenoid, and a character combination composed, among others, of the articulation between the fourth and fifth cervical vertebrae through a cotyle in the fourth and a condyle in the fifth, amphicoelous caudal centra, and most digits of manus and pes with three elongated phalanges. This study allows clarification of the systematic position of a species of uncertain affinity often identified as “chelydroid” in appearance. A phylogenetic analysis shows Hoyasemys jimenezi gen. et sp. nov. forms a monophyletic group with Judithemys sukhanovi, Dracochelys bicuspis, Sinemys lens, and Ordosemys leios, collectively the sister group of crown Cryptodira.

New Crocodyliforms from Southwestern Europe and Definition of a Diverse Clade of European Late Cretaceous Basal Eusuchians

The late Campanian-early Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided a set of well-preserved crocodyliform skull and lower jaw remains, which are described here and assigned to a new basal eusuchian taxon, Lohuecosuchus megadontos gen. et sp. nov. The reevaluation of a complete skull from the synchronous site of Fox-Amphoux (Department of Var, France) allows us to define a second species of this new genus. Phylogenetic analysis places Lohuecosuchus in a clade exclusively composed by European Late Cretaceous taxa. This new clade, defined here as Allodaposuchidae, is recognized as the sister group of Hylaeochampsidae, also comprised of European Cretaceous forms. Allodaposuchidae and Hylaeochampsidae are grouped in a clade identified as the sister group of Crocodylia, the only crocodyliform lineage that reaches our days. Allodaposuchidae shows a vicariant distribution pattern in the European Late Cretaceous archipelago, with several Ibero-Armorican forms more closely related to each other than with to Romanian Allodaposuchus precedens.

Shell bone histology of solemydid turtles (stem Testudines): palaeoecological implications

Lately, solemydid turtles have been repeatedly recovered as stem Testudines, indicating that they belong to neither one of the two major branches of crown turtles, the Pancryptodira and Panpleurodira. Despite their wide temporal (Late Jurassic to Late Cretaceous) and spatial (North America and Europe) distributions, solemydid turtles are not particularly well known, as exemplified by the fact that only a single skull has been described for the whole group so far. Furthermore, the palaeoecology of solemydid turtles is still contested with hypotheses ranging from semi-aquatic to terrestrial lifestyles. However, the habitat preference of stem Testudines, such as solemydids, is important to understand the evolution and early radiation of the turtle crown, which is primitively aquatic. Here we describe the shell bone microanatomy and histological microstructures of solemydid turtles using a broad sample of taxa of different ages and localities, as well as review previous histological accounts, to elucidate the palaeoecology of the group independent of the geological setting and gross anatomy of the fossil finds. Our results indicate that Solemydidae share unique histological features pertaining to their strongly ornamented shell bones, which a) in cases allow taxonomic identification of even small shell fragments and b) unambiguously corroborate a terrestrial lifestyle of its members. The latter further supports a terrestrial lifestyle preference of most representatives of the turtle stem.

A new turtle taxon (Podocnemidoidea, Bothremydidae) reveals the oldest known dispersal event of the crown Pleurodira from Gondwana to Laurasia

Pan-Pleurodira is one of the two clades of extant turtles (i.e. Testudines). Its crown group, Pleurodira, has a Gondwanan origin being known from the Barremian. Cretaceous turtle fauna of Gondwana was composed almost exclusively of pleurodires. Extant pleurodires live in relatively warm regions, with a geographical distribution restricted to tropical regions that were part of Gondwana. Although pleurodires were originally freshwater forms, some clades have adapted to a nearshore marine lifestyle, which contributed to their dispersal. However, few lineages of Pleurodira reached Laurasian regions and no representatives have so far been described from the pre-Santonian of Laurasia, where the continental and coastal Cretaceous faunas of turtles consist of clades exclusive to this region. A new turtle, Algorachelus peregrinus gen. et sp. nov., is described here from the southern Laurasian Cenomanian site of Algora in Spain. Numerous remains, including a skull and well-preserved postcranial specimens, are attributed to this species. The abundant shell elements, much more numerous than those known in most members of pleurodiran clade Bothremydidae, allow its variability to be studied. The new taxon represents the oldest evidence of the occurrence of Pleurodira in Laurasia, and is the oldest genus of the abundant and diverse Bothremydodda so far described. Factors such as the relatively high Cenomanian temperatures, the adaptation of this Gondwanan clade to coastal environments, and the geographical proximity between the two landmasses may have contributed to its dispersal. This finding shows that the first dispersals of Pleurodira from Gondwana to Laurasia occurred much earlier than previously thought. http://zoobank.org/urn:lsid:zoobank.org:pub:8FD358A5-53BD-4308-828A-AC6802184185

The European Early Cretaceous Cryptodiran Turtle Chitracephalus dumonii and the Diversity of a Poorly Known Lineage of Turtles

Chitracephalus dumonii was named based on some of the most complete turtle remains from the Lower Cretaceous of Europe, and yet the taxon has barely been mentioned since. Indeed, new specimens were erroneously attributed to a new taxon, ldquo;Salasemys pulcherrima”. The synonymy is recognized here, and this extends the geographical range of this turtle and provides examples of individuals at different stages of ontogenetic development. The peculiar structure of its shell, and its ontogenetic development, are unique to this taxon. The systematic position of C. dumonii was previously unclear, usually being referred to Testudinata incertae sedis. Here, it is placed in a cladistic analysis, which shows that C. dumonii, and the recently described Hoyasemys jimenezi form part of a Lower Cretaceous European clade of Cryptodira that includes “macrobaenid”, “sinemydid”, and panchelonioidean turtles.

A new turtle confirms the presence of Bothremydidae (Pleurodira) in the Cenozoic of Europe and expands the biostratigraphic range of Foxemydina.

Pleurodira is a clade of Gondwanan turtles that reached Europe at the beginning of the Late Cretaceous. It is recognized as the most abundant and diverse group of freshwater turtles in the uppermost Cretaceous record of this continent, being represented by several members of Bothremydidae. Two well-preserved and relatively complete skulls are studied in this paper. They come from lower Eocene levels of the French locality of Saint-Papoul (Aude). These specimens are recognized as attributable to a new taxon, Tartaruscola teodorii gen. et sp. nov., identified as a bothremydid. This new form constitutes the only known unambiguous and valid representative of Bothremydidae in the Cenozoic of Europe. The new taxon is diagnosed by several autapomorphies and also by an exclusive combination of characters. It is one of the few members of Bothremydini identified in the Cenozoic record and the only one described for the Eocene outside of the Ouled Abdoun Basin of Morocco. Tartaruscola teodorii is identified as a member of Foxemydina, a clade recognized here as exclusive of the European record, and whose presence in post-Mesozoic levels is demonstrated in this paper. The European Foxemydina T. teodorii and the African Bothremydina Bothremys kellyi, both from the Ypresian, are the youngest members of Bothremydini hitherto known.

New insights into the anatomy and systematic of ‘Papoulemys’ laurenti, a representative of Neochelys (Chelonii, Podocnemididae) from the early Eocene of the south of France

Neochelys is a European Eocene genus of turtles well represented by various species. It is one of the few members of Pleurodira identified during the Cenozoic of this continent. However, it has generally been recognized only by shells, and too few skulls are known to provide useful data for comparative diagnosis and relationships. The European Eocene ‘Papoulemys’ had been proposed as a junior synonym of Neochelys, the species ‘P.’ laurenti becoming N. laurenti, but this hypothesis was insufficiently justified. A second skull of this species, from its type locality (the French locality of Saint-Papoul), is analysed here together with several unpublished skulls of other Neochelys spp. from various countries and ages, providing new arguments to refute the validity of the characters used to diagnose ‘Papoulemys’ as a genus distinct from Neochelys. They are exclusively cranial characters since only its holotype (a skull) was known. Several shells from the type locality, on which the reattribution to N.laurenti had been proposed (but only synthetically), are also studied in detail here, as well as other unpublished Neochelys spp. shells. We propose a new diagnosis for ‘Papoulemys’ laurenti, reallocating the species to Neochelys. We also expand the available information on this genus and on several of its representatives.KurzfassungNeochelys war eine im Eozän Europas weit verbreitete und vielfältige Schildkrötengattung, wobei sie eines der wenigen Mitglieder der Pleurodira darstellt, die im Känozoikum dieses Kontinents identifiziert worden sind. Allerdings wurde sie im Allgemeinen anhand des Panzers erkannt, da ihre kraniale Information begrenzt ist. Einige Autoren legten ‘Papoulemys’ aus dem europäischen Eozän als jüngeres Synonym von Neochelys nahe, so dass die Spezies ‘P.’ laurenti zu N. laurenti wurde. Diese Hypothese wurde nur unzureichend begründet. Die Untersuchung eines zweiten Schädels in Hinblick auf die Zuordnung des Fundes sowie die Analyse weiterer nicht veröffentlichter Schädel anderer Neochelys-Arten aus unterschiedlichen Ländern und Zeitaltern bietet neue Argumente, die es ermöglichen die Gültigkeit der Figuren, die ‘Papoulemys’ als von Neochelys verschiedene Gattung zu widerlegen. Diese entsprachen ausschließlich kranialen Figuren, da nur ihr Holotypus, ein Schädel, bekannt war. Mehrere Panzer dieser Fundzuordnung, in der die Wiederzuschreibung zu N. laurenti stattfand, allerdings nur auf eine eine synthetische Weise, werden hier ebenfalls im Detail untersucht, ebenso wie weitere unveröffentlichte Panzer von Neochelys-Arten. Dies ermöglicht es, die Gültigkeit der Art ‘Papoulemys’ laurenti zu bestätigen, für die eine neue Diagnose vorgestellt wird. Die Neuzuordnung dieser Art zu Neochelys ist begründet, da sich Kenntnisse von dieser Gattung und mehreren ihrer Vertreter verbessert haben.

The Erymnochelys group of turtles (Pleurodira, Podocnemididae) in the Eocene of Europe: New taxa and paleobiogeographical implications

The Erymnochelys group is a lineage of Erymnochelyinae, pleurodiran turtles that originated in Africa, with a fossil record extending from the Late Cretaceous. It is currently represented by a single species, the Malagasy Erymnochelys madagascariensis. Information on most of its fossil representatives is sparse. In fact, the oldest unambiguous generic determinations heretofore established within the group are those of Turkanemys and Kenyemys, both from the latest Miocene-Pliocene of Kenya. The description and illustration of the French middle Eocene species ‘aff. Erymnochelys’ eremberti is completed here, and a diagnosis for this species is proposed for the first time. It is attributed to a new genus, Eocenochelus, the first genus of the Erymnochelys group defined outside of Africa. Eocenochelus is also recognized in the European lower and upper Eocene record by two new species, Eocenochelus lacombianus and Eocenochelus farresi, respectively. Therefore, Eocenochelus is a taxon with a wide distribution in Europe during the Eocene and is relatively diverse. This is also the case with the continental Neochelys, the only other podocnemidid genus so far recognized in the European Paleogene record. Exclusively identified in coastal deposits, Eocenochelus is the only known form of the Erymnochelys group found in marginal marine sediments. Its anatomical adaptations probably facilitated the spread from Africa to Europe. Adán Pérez-García. Grupo de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Paseo de la Senda del Rey 9, 28040 Madrid, Spain. paleontologo@gmail.com France de Lapparent de Broin. Centre de Recherche sur la Paléodiversité et les Paléoenvironnements, Muséum national d’Histoire naturelle, 57 rue Cuvier, CP 38, 75231 Paris cedex 5, France. france.lapparent@sfr.fr Xabier Murelaga. Departamento de Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apartado 644, 48080 Bilbao, Spain. xabier.murelaga@ehu.eus http://zoobank.org/1D985176-5AD4-45FF-8BD7-C4AD17C7DE52 Pérez-García, Adán, de Lapparent de Broin, France, and Murelaga, Xabier. 2017. The Erymnochelys group of turtles (Pleurodira, Podocnemididae) in the Eocene of Europe: New taxa and paleobiogeographical implications. Palaeontologia Electronica 20.1.14A:

Reinterpretation of the Spanish Late Jurassic “Hispaniachelys prebetica” as an Indeterminate Plesiochelyid Turtle

A partial postcranial skeleton (carapace, plastron, and other poorly preserved elements) of a turtle, from the late Oxfordian of the Betic Range of Spain, has recently been assigned to a new taxon, Hispaniachelys prebetica. This is one of the few European turtle taxa reported from pre-Kimmeridgian levels, and the oldest turtle so far known from southern Europe. The character combination identified in that taxon (including the presence of cleithra, and single cervical scale) did not allow its assignment to Plesiochelyidae, a group of turtles very abundant and diverse in the Late Jurassic of Europe. The revision of the single specimen assigned to this taxon led to the reinterpretation of some of its elements, being reassigned to Plesiochelyidae. This study confirms the presence of Plesiochelyidae in the Oxfordian. However, because the Spanish taxon does not present a unique combination of characters, it is proposed as a nomen dubium.