Yelaphomte
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''Yelaphomte'' ( Allentiac, "beast of the air") is an
extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of non- pterodactyloid
pterosaur Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...
from the late
Norian The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic defi ...
–early
Rhaetian The Rhaetian is the latest age of the Triassic Period (in geochronology) or the uppermost stage of the Triassic System (in chronostratigraphy). It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age ...
-aged
Quebrada del Barro Formation The Quebrada del Barro Formation is a geological formation of the Marayes-El Carrizal Basin in San Juan Province, Argentina. This formation is the most fossiliferous portion of the Triassic Marayes Group, and is also the youngest unit of the gro ...
of
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. It lived in the
Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...
period, and is one of the only known definitive
Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
pterosaurs from the southern hemisphere (along with the contemporaneous and related ''
Pachagnathus ''Pachagnathus'' ("earth jaw") is an extinct genus of non- pterodactyloid pterosaur from the late Norian–early Rhaetian-aged Quebrada del Barro Formation of Argentina. It lived in the Late Triassic period, and is one of the only known definiti ...
''). It was a small and crested pterosaur, although its small size may be due to immaturity. It is also one of the few known continental Triassic pterosaurs, indicating that the absence of early pterosaurs in both the southern hemisphere and terrestrial environments is likely a sampling bias, and not a true absence.


Discovery and naming

The type and only known specimen of ''Yelaphomte'', PVSJ 914, was collected during fieldwork by the Museo de Ciencias Naturales of the Universidad Nacional de San Juan from 2012 to 2014. It consists of only a fragment of the rostrum preserving the anterior part of both
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
e and palatines from the anterior border of the
naris A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...
, as well as a posterior portion of both
premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...
e, all preserved in three dimensions and undistorted. It was first reported on in 2015 by Martínez ''et al.'', although at the time the specimen was not fully prepared and could not be identified as anything more diagnostic than an indeterminate pterosaur. PVSJ 914 was later fully described and named by Martínez ''et al.'' (2022) as a new genus and species, ''Yelaphomte praderioi'', along with other pterosaur remains from the Quebrada del Barro Formation (including the related ''Pachagnathus''). The specimen was discovered at the ‘Quebrada del Puma’ locality of the Quebrada del Barro Formation within the Marayes–El Carrizal Basin of Northwestern Argentina, part of the
Caucete Department Caucete is a department in the eastern part of the San Juan Province of Argentina, which is predominantly a landscape of mountains, and many plantations. It contains the popular Shrine of the Difunta Correa. Etymology The name is derived from ...
in the San Juan Province. The 'Quebrada del Puma' locality occurs in the upper layers of the Quebrada del Barro Formation in its southern outcrops, and has been roughly dated to around the late
Norian The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic defi ...
into the
Rhaetian The Rhaetian is the latest age of the Triassic Period (in geochronology) or the uppermost stage of the Triassic System (in chronostratigraphy). It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age ...
based on its faunal assemblages. PVSJ 914 was discovered in a horizon of reddish muddy
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...
60 m below the top of the formation, beneath the unconformably overlying
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
aged
El Gigante Group EL, El or el may refer to: Religion * El (deity), a Semitic word for "God" People * EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer * El DeBarge, music artist * El Franco Lee (1949–2016), American po ...
. The generic name is from Allentiac, the native language of the
Huarpe The Huarpes or Warpes are an indigenous people of Argentina, living in the Cuyo region. Some scholars assume that in the Huarpe language, this word means "sandy ground," but according to ''Arte y Vocabulario de la lengua general del Reino de Chi ...
people indigenous to the San Juan Province. It combines ''yelap'' ("beast") and ''homtec'' ("air"), referring both the extensively air-filled pneumatic spaces in its snout as well as its ability to fly. The species name honours Angel Praderio, a member of the fossil hunting team who discovered PVSJ 914.


Description

''Yelaphomte'' is a small pterosaur known by a partial rostrum only 15.4 mm long, preserving parts of its maxillae, premaxillae and palatine bones. The main body of the preserved snout is narrow and roughly triangular in shape tapering towards the unpreserved snout tip. The premaxilla contacts the maxilla along a long, straight suture that runs from the bottom corner of the front of the naris down to the bottom corner of the preserved portion of the snout. This suture is only visible in
CT scans A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
and the bones were tightly fused together. The premaxillae themselves are similarly fused, and sport part of a prominent crest running along the top of the snout. This narrow bony crest is tall and thin, resembling those of the related ''
Raeticodactylus ''Raeticodactylus'' is a genus of non- pterodactyloid pterosaur from the late Norian-early Rhaetian-age Upper Triassic lower Kössen Formation of the central Austroalpine of Grisons, Switzerland. It is known from holotype BNM 14524, a single ...
'' and '' Austriadactylus''. Although the edges of the crest are all broken and its size cannot be definitively determined, the thickness of the preserved portion and low degree of tapering suggests it was much taller and longer than preserved. The crest is ornamented with a series of well-spaced radiating grooves on each side. Similar ornamentations of radial striations are found on the crests of ''Raeticodactylus'' and ''Austriadactylus'' as well, but unlike ''Yelaphomte'' they possess closely packed alternating ridges and grooves, and the ornamentation pattern of ''Yelaphomte'' is unique amongst pterosaurs. The broken snout tip and CT scanning revealed extensive pneumatic spaces in the premaxilla separated by intricate struts of bony trabeculae. These trabeculae are symmetrical, with two along the midline and four each laterally at the breakage. These air spaces converge into three cavities further back, and then into a single large, deep chamber ahead of the narial opening. Pneumatic bones are characteristic of pterosaurs in general, but the complex array of trabeculae suggests an even greater degree of pneumatisation in ''Yelaphomte'' than normal. The cheek teeth are poorly preserved, with only the roots left in the tooth sockets. Like other eopterosaur teeth, they are closely spaced (less than a tooth width apart), evenly distributed, and are positioned vertically without splaying to the side. However, unusually the tooth roots are angled roughly 60° to the jaw margin, suggesting that the cheek teeth were angled forwards (procumbent). This differs from both the straight and upright cheek teeth of other eopterosaurs, as well as the procumbent and splayed teeth of rhamphorhynchids—although it is uncertain if the tooth crowns themselves were as procumbent as the roots. In front of the cheek teeth is a large toothless gap, a
diastema A diastema (plural diastemata, from Greek διάστημα, space) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition ...
, extending to the front of the maxilla. This is a feature it shares with ''Raeticodactylus'', but in ''Yelaphomte'' the diastema is notably larger, longer than the space occupied by four of the spaced cheek teeth.


Classification

To determine the relationships of ''Yelaphomte'' to other pterosaurs, Martínez and colleagues performed a phylogenetic analysis using an updated version of the pterosaur data matrix published by Andres et al. (2014). This analysis recovered ''Yelaphomte'' as a member of Raeticodactylidae, but couldn't resolve its relationships to ''Raeticodactylus'' and ''Pachagnathus'' beyond a polytomy of the three species due to a lack of overlapping material. A simplified version of their results focused on Eopterosauria is shown in the cladogram below: An additional analysis using the diapsid reptile data matrix of Ezcurra ''et al.'' (2020) was also used to confirm the inclusion of ''Yelaphomte'' within pterosaurs more broadly. This analysis found ''Yelaphomte'' in essentially the same position as the Andres ''et al.'' dataset in a polytomy with ''Raeticodactylus'' and '' Carniadactylus''. Although no diagnostic traits of Raeticodactylidae are present in the known material of ''Yelaphomte'', a close relationship to ''Raeticodactylus'' is supported by its evenly spaced teeth, as well as similarities such as its crest and the presence of a diastema.


Palaeobiology

The small size of ''Yelaphomte'' suggests that the specimen could belong to an immature individual, and consequently the differences between it and the contemporary raeticodactylid ''Pachagnathus'' could be due to
ontogeny Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the stu ...
. However, Martínez and colleagues concluded this was unlikely, as the high degree of fusion in its snout may be indicative of its maturity and suggests a small adult size—although they note that the rostrum and mandible bones of pterosaurs do fuse at a young age.


Palaeoecology

''Yelaphomte'' lived in a continental environment a long distance from the nearest coast, and was therefore almost certainly a terrestrial animal, compared to the various coastal Triassic pterosaurs found in the northern hemisphere. This corroborates hypotheses that significant parts of early pterosaur evolution may have taken place in terrestrial settings. The Quebrada del Barro Formation has also produced remains of the related larger pterosaur ''Pachagnathus'', as well as a diverse range of vertebrate fossils including
dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
—such as the predatory theropod ''
Lucianovenator ''Lucianovenator'' is an extinct genus of coelophysidae, coelophysid Theropoda, theropod dinosaur which lived in Argentina during the Triassic. The genus name ''Lucianovenator'' translates to "Luciano's hunter", in reference to Don Luciano Leyes, ...
'' and the and large sauropodomorph ''
Ingentia ''Ingentia'' is a genus of early sauropod dinosaur from the Late Triassic (late Norian-Rhaetian) of Argentina. The type specimen of ''Ingentia'', PVSJ 1086, was discovered in the Quebrada del Barro Formation of northwestern Argentina. It was des ...
''—the
lagerpetid Lagerpetidae (; originally Lagerpetonidae) is a family of basal avemetatarsalians. Though traditionally considered the earliest-diverging dinosauromorphs (reptiles closer to dinosaurs than to pterosaurs), fossils described in 2020 suggest that ...
''
Dromomeron ''Dromomeron'' (meaning "running femur") is a genus of lagerpetid avemetatarsalian which lived around 220 to 211.9 ± 0.7 million years ago. The genus contains species known from Late Triassic-age rocks of the Southwestern United States and nort ...
'', predatory
rauisuchid Rauisuchidae is a group of large (up to or more) predatory Triassic archosaurs. There is some disagreement over which genera should be included in Rauisuchidae and which should be in the related Prestosuchidae and Poposauridae, and indeed whethe ...
and small
crocodylomorph Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. During Mesozoic and early Cenozoic times, cro ...
pseudosuchians Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Prior to ...
, the opisthodont
sphenodontian Rhynchocephalia (; ) is an order of lizard-like reptiles that includes only one living species, the tuatara (''Sphenodon punctatus'') of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a diverse g ...
'' Sphenotitan'', the australochelyid stem-turtle '' Waluchelys'', and undescribed tritheledontid
cynodonts The cynodonts () (clade Cynodontia) are a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Cynodonts had a wide variety ...
.


See also

* List of pterosaur genera * Timeline of pterosaur research


References

{{Taxonbar, from=Q111286457 Pterosaurs Late Triassic pterosaurs Fossils of Argentina Triassic Argentina Fossil taxa described in 2022