scholarly journals A case of mistaken identity: ‘Latvius’ obrutus and new dipnoans from the Frasnian of Stolbovo, Russia

Author(s):  
Tom Challands ◽  
Oleg Lebedev ◽  
Matt Friedman ◽  
Natasha Krupina

The village of Stolbovo, western Russia, has previously yielded a dipnoan fauna comprising the long-snouted form 'Rhinodipterus' stolbovi, but also a three-dimensionally preserved otoccipital region of a skull previously identified as the osteolepiform ‘Latvius’ obrutus. This identification was made from the density of lateral line canal pores in the skull roof bones in addition to what Vorobyeva (1977) described as the post-parietal, tabular and extratabular bones. Reexamination of this specimen does not recognise the osteolepiform dermal elements previously identified but rather a dipnoan configuration including a characteristic B-bone, lateral dermal elements and a dipnoan parasphenoid. rhinodipterid and dipterid dipnoans. Phylogenetic analysis resolves ‘Latvius’ obrutus as the primitive sister taxon to the ‘phaneropleurid-fleurantiid’ clade – a clade comprising derived Middle–Upper Devonian lungfishes. 'Rhinodipterus' stolbovi resolves among the more primitive griphognathids, typical Gondwanan forms, and is not a rhinodipterid. Additional isolated dipnoan skeletal elements from the site include tooth plates, parasphenoids, shoulder girdle elements and dermal elements and indicate at least an additional three lungfish taxa from Stolbovo. Of particular note is a ctenodiform tooth plate more characteristic of Carboniferous lungfishes. The new material and analyses not only demonstrate increased lungfish diversity from the Frasnian of Baltica but also probable interchange between Gondwana and Baltica during this time. Most importantly, Carboniferous-like forms appear more common in the Devonian than previously realised indicating that Carboniferous lungfishes likely represent a survival assemblage in addition to a new radiation of lungfish.

Author(s):  
Tom Challands ◽  
Oleg Lebedev ◽  
Matt Friedman ◽  
Natasha Krupina

The village of Stolbovo, western Russia, has previously yielded a dipnoan fauna comprising the long-snouted form 'Rhinodipterus' stolbovi, but also a three-dimensionally preserved otoccipital region of a skull previously identified as the osteolepiform ‘Latvius’ obrutus. This identification was made from the density of lateral line canal pores in the skull roof bones in addition to what Vorobyeva (1977) described as the post-parietal, tabular and extratabular bones. Reexamination of this specimen does not recognise the osteolepiform dermal elements previously identified but rather a dipnoan configuration including a characteristic B-bone, lateral dermal elements and a dipnoan parasphenoid. rhinodipterid and dipterid dipnoans. Phylogenetic analysis resolves ‘Latvius’ obrutus as the primitive sister taxon to the ‘phaneropleurid-fleurantiid’ clade – a clade comprising derived Middle–Upper Devonian lungfishes. 'Rhinodipterus' stolbovi resolves among the more primitive griphognathids, typical Gondwanan forms, and is not a rhinodipterid. Additional isolated dipnoan skeletal elements from the site include tooth plates, parasphenoids, shoulder girdle elements and dermal elements and indicate at least an additional three lungfish taxa from Stolbovo. Of particular note is a ctenodiform tooth plate more characteristic of Carboniferous lungfishes. The new material and analyses not only demonstrate increased lungfish diversity from the Frasnian of Baltica but also probable interchange between Gondwana and Baltica during this time. Most importantly, Carboniferous-like forms appear more common in the Devonian than previously realised indicating that Carboniferous lungfishes likely represent a survival assemblage in addition to a new radiation of lungfish.


2001 ◽  
Vol 49 (5) ◽  
pp. 487 ◽  
Author(s):  
S. Wroe ◽  
A. Musser

The exceptionally well preserved skull and mandible of the Miocene thylacinid Nimbacinus dicksoni is described. Phylogenetic analysis supports the contention that, within the family, the dentition of N. dicksoni is unspecialised, less derived than the recent Thylacinus cynocephalus for at least 12 features. However, relatively few cranial specialisations evident in T. cynocephalus clearly distinguish it from N. dicksoni. These two taxa share at least three derived cranial features not present in the most generalised thylacinid known from significant cranial material, the late Oligocene Badjcinus turnbulli. On the other hand, where comparison is possible, even the most specialised thylacinid, T. cynocephalus, is plesiomorphic for at least 10 cranial features common to modern dasyurids and five present in the Miocene dasyurid, Barinya wangala. Two character states found in thylacinids are more derived than in B. wangala. Relative to the remaining dasyuromorphian family, Myrmecobiidae, represented by the monotypic Myrmecobius fasciatus, thylacinids are derived for five cranial features and plesiomorphic for five. It appears that despite considerable anatomical diversity among the dentitia of thylacinids and the presence of many highly specialised dental features in some species, the crania of thylacinids have remained remarkably conservative. Even with respect to dentitia, in terms of overall similarity, the Miocene Thylacinus macknessiand late Oligocene material referred to Thylacinus does not differ greatly from the recently extinct T. cynocephalus. It now also seems probable that T. macknessi was also very similar to T. cynocephalus with respect to cranial anatomy. Numerical parsimony analysis incorporating this new material produced moderate bootstrap and Bremer support for a monophyletic Thylacinidae. In this same treatment strict consensus placed Myrmecobius fasciatus as the sister taxon to Thylacinidae–Dasyuridae, but bootstrap and Bremer support was lacking. Both of these results are contra those of the most recent attempt to resolve dasyuromorphian relationships using numerical parsimony and anatomical data. In the present analysis, the early Eocene Australian taxon, Djarthia murgonensis, fell outside a clade inclusive of all other Australian taxa and was monophyletic with the borhyaeniod, Mayulestes ferox. This latter relationship is based on limited material, poorly supported and considered highly unlikely, but it does strengthen the argument that formal placement of D. murgonensis beyond the level of Marsupialia incertae sedisis unwarranted at present.


Author(s):  
Natalya A. Lejbova ◽  
Umalat B. Gadiev

Although population of the Caucasus has been studied in a rather detailed way, there are peoples whose anthropological portrait is still incomplete. Among them are the Ingush, one of the oldest autochthonous peoples of the Caucasus. This work presents new material on the dental anthropology of medieval Ingush, collected in 2017 during expeditions to the Jairakh and Sunzhen districts of the Republic of Ingushetia. In the Jairakh district, the investigations were carried out in the crypt complexes of the 15th–18th centuries – Targim, Agikal, Tsori, Salgi, and in Sunzhen region - in crypts near the village of Muzgan. The craniological series of medieval Ingush studied according to the dental anthropology program can be described as belonging to the western range of odontological complexes. Unlike most modern Caucasian groups, it does not belong to gracile forms, but rather to a maturized odontological variant, which has deep roots in the Caucasus. The results once again demonstrate a certain conservatism and stability of the dental system, which preserves morphological traits of ancestral groups longer than other anthropological systems.


2020 ◽  
pp. 1-17
Author(s):  
Thomas E. Guensburg ◽  
James Sprinkle ◽  
Rich Mooi ◽  
Bertrand Lefebvre

Abstract Twelve specimens of Eumorphocystis Branson and Peck, 1940 provide the basis for new findings and a more informed assessment of whether this blastozoan (a group including eocrinoids, blastoids, diploporites, rhombiferans) constitutes the sister taxon to crinoids, as has been recently proposed. Both Eumorphocystis and earliest-known crinoid feeding appendages express longitudinal canals, a demonstrable trait exclusive to these taxa. However, the specimen series studied here shows that Eumorphocystis canals constrict proximally and travel within ambulacrals above the thecal cavity. This relationship is congruent with a documented blastozoan pattern but very unlike earliest crinoid topology. Earliest crinoid arm cavities lie fully beneath floor plates; these expand and merge directly with the main thecal coelomic cavity at thecal shoulders. Other associated anatomical features echo this contrasting comparison. Feeding appendages of Eumorphocystis lack two-tiered cover plates, podial basins/pores, and lateral arm plating, all features of earliest crinoid ‘true arms.’ Eumorphocystis feeding appendages are buttressed by solid block-like plates added during ontogeny at a generative zone below floor plates, a pattern with no known parallel among crinoids. Eumorphocystis feeding appendages express brachioles, erect extensions of floor plates, also unknown among crinoids. These several distinctions point to nonhomology of most feeding appendage anatomy, including longitudinal canals, removing Eumorphocystis and other blastozoans from exclusive relationship with crinoids. Eumorphocystis further differs from crinoids in that thecal plates express diplopores, respiratory structures not present among crinoids, but ubiquitous among certain groups of blastozoans. Phylogenetic analysis places Eumorphocystis as a crownward blastozoan, far removed from crinoids.


2018 ◽  
Vol 74 (3-4) ◽  
pp. 245-291
Author(s):  
Stanislav Štamberg

Actinopterygians from the large opencast coal mine in the vicinity of the village of Buxières-les-Mines (Bourbonl’Archambault Basin, Allier, France) are revisited and redescribed based on newly studied specimens. The understanding of the anatomy of Progyrolepis heyleri POPLIN, 1999, originally described by Poplin (1999) on the basis of the upper and lower jaws only, is greatly enhanced and is relatively complete. The anatomy of the palatoquadrate, dermal bones of the skull roof, hyoid arch, operculum, suboperculum, shoulder girdle, cheek bones and branchiostegal rays is described. In addition, new observations have been made on changes in the shape of the maxilla during ontogenesis and microstructure of the teeth. Details of Progyrolepis heyleri scales, including their microstructure and morphology of the ridge scales are provided. The collection of whole individuals, body fragments and numerous isolated bones provide confirmation of the presence of Aeduella blainvillei which is the main component of the actinopterygian fauna in Buxières-les-Mines. Additional new knowledge was obtained regarding the great variability in bones of the opercular apparatus and maxilla, presence of the supraorbital, branchiostegal ray with a conspicuous hyoid process and the direction of mutual overlapping of the suboperculum and branchiostegal ray in Aeduella blainvillei (AGASSIZ, 1833). Microsculpture on the scales is redescribed in this species. Paramblypterus cf. duvernoy is the third member of the actinopterygians in the locality Buxières-les-Mines. Fragments of Paramblypterus are very rare and the bones of the skull roof are presented here. Anatomical features of Progyrolepis heyleri, Aeduella blainvillei and Paramblypterus cf. duvernoy were studied and compared with those of other Devonian and Permo-Carboniferous actinopterygians.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5300
Author(s):  
Terry A. Gates ◽  
Khishigjav Tsogtbaatar ◽  
Lindsay E. Zanno ◽  
Tsogtbaatar Chinzorig ◽  
Mahito Watabe

We describe a new iguanodontian ornithopod,Choyrodon barsboldigen. et sp. nov. from the Albian-aged Khuren Dukh Formation of Mongolia based on several partial skeletons interpreted to represent a subadult growth stage based on osteohistological features. This new taxon is diagnosed by many autapomorphies of the maxilla, nasal, lacrimal, opisthotic, predentary, and surangular.Choyrodondisplays an unusual combination of traits, possessing an open antorbital fenestra (a primitive ornithopod trait) together with derived features such as a downturned dentary and enlarged narial fenestra. Histological imaging suggests that the type specimen ofChoyrodonwould have been a subadult at the time of death. Phylogenetic analysis of two different character matrices do not positChoyrodonto be the sister taxon or to be more primitive than the iguanodontianAltirhinus kurzanovi, which is found in the same formation. The only resolved relationship of this new taxon is that it was hypothesized to be a sister-taxon with the North American speciesEolambia caroljonesa. Though discovered in the same formation andChoyrodonbeing smaller-bodied thanAltirhinus, it does not appear that the former species is an ontogimorph of the latter. Differences in morphology and results of the phylogenetic analyses support their distinction although more specimens of both species will allow better refinement of their uniqueness.


Zootaxa ◽  
2021 ◽  
Vol 4926 (2) ◽  
pp. 151-188
Author(s):  
JAVIER FRESNEDA ◽  
VALERIA RIZZO ◽  
JORDI COMAS ◽  
IGNACIO RIBERA

We redefine the genus Troglocharinus Reitter, 1908 based on a phylogenetic analysis with a combination of mitochondrial and molecular data. We recovered the current Speonomites mengeli (Jeannel, 1910) and S. mercedesi (Zariquiey, 1922) as valid, separate species within the Troglocharinus clade, not directly related to Speonomites Jeannel, 1910, a finding corroborated by a detailed study of the male and female genitalia. In consequence, we reinstate Speonomus mercedesi Zariquiey, 1922 stat. nov. as a valid species, transfer both of them to the genus Troglocharinus, T. mengeli (Jeannel, 1910) comb. nov. and T. mercedesi (Zariquiey, 1922) comb. nov., and redescribe the genus. The study of new material from the distribution area of the former S. mengeli revealed the presence of two undescribed species, T. sendrai sp. nov. and T. fadriquei sp. nov., which we describe herein. We designate the lectotype of Speonomus vinyasi Escolà, 1971 to fix its identity, as among its syntypes there are two different species. In agreement with the results of the phylogenetic analyses we establish the synonymy between the genus Speonomites and Pallaresiella Fresneda, 1998 syn. nv. 


2019 ◽  
Vol 94 (3) ◽  
pp. 568-579
Author(s):  
Alexander O. Averianov

AbstractKazachostylops occidentalis Nesov, 1987b, based on partial maxilla and dentary from the upper Paleocene Zhylga locality in South Kazakhstan, is redescribed. A new phylogenetic hypothesis of Arctostylopida is proposed based on phylogenetic analysis of 26 characters and 17 taxa. Kazachostylops is recovered as a sister taxon to the Arctostylopinae, the advanced clade of Asian and North American arctostylopids characterized by pseudohypocone on upper molars and reduced trigonid of lower molars, with the ectolophid being attached labial on the trigonid. Kazachostylops differs from more basal arctostylopids (Asiostylops, Allostylops, Bothriostylops, and Wanostylops) by higher-crowned molars, M1–3 metaconule absent, m1–3 entoconid connected with ectolophid by entolophid, and m2 wider than m1 and m3. Principal component analyses of the upper and lower dentition of arctostylopids show great distinctness of Kazachostylops from other members of the group. The arctostylopid taxa are reviewed, and the new genus Enantiostylops is erected for ‘Sinostylops’ progressus Tang and Yan, 1976 from the lower Eocene of China, because of uniquely concave parastylar area on upper molars.UUID: http://zoobank.org/a46d8f29-fd73-4e59-88dc-fcc55b12d1d3


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Adele H. Pentland ◽  
Stephen F. Poropat ◽  
Travis R. Tischler ◽  
Trish Sloan ◽  
Robert A. Elliott ◽  
...  

Abstract The Australian pterosaur record is poor by world standards, comprising fewer than 20 fragmentary specimens. Herein, we describe the new genus and species Ferrodraco lentoni gen. et sp. nov., based on the most complete pterosaur specimen ever found in Australia, and the first reported from the Winton Formation (Cenomanian–lower Turonian). The presence of premaxillary and mandibular crests, and spike-shaped teeth with subcircular bases, enable Ferrodraco to be referred to Anhangueria. Ferrodraco can be distinguished from all other anhanguerian pterosaurs based on two dental characters: the first premaxillary and mandibular tooth pairs are small; and the fourth–seventh tooth pairs are smaller than the third and eighth ones. Ferrodraco was included in a phylogenetic analysis of Pterosauria and resolved as the sister taxon to Mythunga camara (upper Albian Toolebuc Formation, Australia), with that clade occupying the most derived position within Ornithocheiridae. Ornithocheirus simus (Albian Cambridge Greensand, England), Coloborhynchus clavirostris (Valanginian Hastings Sands, England), and Tropeognathus mesembrinus (upper Aptian–lower Albian Romualdo Formation, Brazil) were resolved as successive sister taxa, which suggests that ornithocheirids were cosmopolitan during the Albian–Cenomanian. Furthermore, the stratigraphic age of Ferrodraco lentoni (Cenomanian–lower Turonian) implies that anhanguerians might have survived later in Australia than elsewhere.


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