scholarly journals Upside down: ‘Cryobatrachus’ and the lydekkerinid record from Antarctica

2021 ◽  
pp. 1-26
Author(s):  
Bryan M. Gee ◽  
Peter J. Makovicky ◽  
Christian A. Sidor
Keyword(s):  
Middle Triassic ◽  
Lower Triassic ◽  
Type Specimen ◽  
Nomen Dubium ◽  
The Family ◽  
Tomographic Analysis

Abstract Temnospondyl amphibians are common in non-marine Triassic assemblages, including in the Fremouw Formation (Lower to Middle Triassic) of Antarctica. Temnospondyls were among the first tetrapods to be collected from Antarctica, but their record from the lower Fremouw Formation has long been tenuous. One taxon, ‘Austrobrachyops jenseni,’ is represented by a type specimen comprising only a partial pterygoid, which is now thought to belong to a dicynodont. A second taxon, ‘Cryobatrachus kitchingi,’ is represented by a type specimen comprising a nearly complete skull, but the specimen is only exposed ventrally, and uncertainty over its ontogenetic maturity and some aspects of its anatomy has led it to be designated as a nomen dubium by previous workers. Here, we redescribe the holotype of ‘C. kitchingi,’ an undertaking that is augmented by tomographic analysis. Most of the original interpretations and reconstructions cannot be substantiated, and some are clearly erroneous. Although originally classified as a lydekkerinid, the purported lydekkerinid characteristics are shown to be unfounded or no longer diagnostic for the family. We instead identify numerous features shared with highly immature capitosaurs, a large-bodied clade documented in the upper Fremouw Formation of Antarctica and elsewhere in the Lower Triassic. Additionally, we describe a newly collected partial skull from the lower Fremouw Formation that represents a relatively mature, small-bodied individual, which we provisionally refer to Lydekkerinidae; this specimen represents the most confident identification of a lydekkerinid from Antarctica to date.

Helmolepis cyphognathus, sp. nov., a new platysiagid actinopterygian from the Lower Triassic Sulphur Mountain Formation (British Columbia, Canada)

2005 ◽  
Vol 42 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Andrew G Neuman ◽  
Raoul J Mutter
Keyword(s):  
British Columbia ◽  
New Species ◽  
Central Europe ◽  
Middle Triassic ◽  
Lower Triassic ◽  
Western Canada ◽  
Early Triassic ◽  
East Greenland ◽  
The Family ◽  
A New Species

A new species of stem actinopterygian, Helmolepis cyphognatus sp. nov., is reported from the Lower Triassic Sulphur Mountain Formation of western Canada (probably Smithian). This taxon differs from the only other known Early Triassic platysiagid, H. gracilis from the Lower Triassic Wordie Creek Formation of East Greenland (Griesbachian), in counts of branchiostegal rays, shape of the maxilla, shape (and possibly counts) of extrascapulars, and the size ratio of major opercular bones. In spite of their overall unfavorable preservation, the numerous available specimens amend our knowledge of the little known genus Helmolepis considerably: it has become evident that the morphology of Helmolepis cyphognatus sp. nov. comes closest to Platysiagum minus (Middle Triassic Besano Formation of central Europe). This study suggests placement of the two genera in the family Platysiagidae. Investigation of this new species also shows certain features of the cheek and the caudal fin are more primitive than previously believed, whereas the snout region is probably derived but of yet uncertain affinities in Helmolepis.

New Triassic dicynodonts from South America, their origins and relationships

1965 ◽  
Vol 248 (753) ◽  
pp. 457-514 ◽  
Keyword(s):  
New Genus ◽  
Middle Triassic ◽  
Taxonomic Status ◽  
Lower Triassic ◽  
Upper Permian ◽  
South American ◽  
Black Rhinoceros ◽  
The Family ◽  
White Rhinoceros ◽  
African Genus

Richly fossiliferous deposits have been found in the Ischigualasto region of Argentina in the last few years. The only known dicynodont from this area is the new genus Ischigualastia , of which a diagnosis and fully illustrated description are given. A specimen from Brazil, which had earlier been referred to the genus Stahleckeria as S. lenzii , is shown to be very similar to Ischigualastia , but not generically identical with it; this specimen is therefore placed in the new genus Barysoma . The only South American dicynodont which had previously been fully described is Stahleckeria , from Brazil. A diagnosis and fully illustrated description are now given of the complete skeleton of the genus Dinodontosaurus , also from Brazil. Earlier Brazilian material which had been referred to the African genus Dicynodon is shown to belong to Dinodontosaurus . A very large skull from the same deposits is identical with Dinodontosaurus , except that it has a much more massive snout and tusks, and a wider occiput. The dicynodonts are herbivorous, and may well have lived in herds; it is suggested that the massive skull may belong to the old male of such a herd of Dinodontosaurus , and it is therefore not given separate taxonomic status. The skull of Placerias , the only dicynodont known from North America, had previously been restored by Camp & Welles (1956) from the broken remains of about forty individuals. Comparison of the restored skull with that of Ischigualastia has suggested various modifications in the reconstruction, and illustrations of the new reconstruction are given. The relationships of the Triassic dicynodonts are discussed. It is suggested that, excluding the specialized genus Lystrosaurus , they show two main divergent adaptations, which are probably related to their mode of feeding. A pointed snout and high occiput is thought to characterize the family Kannemeyeriidae (which includes the forms Kannemeyeria, ‘Kannemeyeria’ vanhoepeni, Sinokannemeyeria, Parakannemeyeria, Ischigualastia, Barysoma and Placerias ). A blunt snout and wide occiput is thought to characterize the family Stahleckeriidae (which includes the genera Stahleckeria and Dinodontosaurus ). A similar distinction is found today between the browsing black rhinoceros and the grazing white rhinoceros. The most primitive kannemeyeriids are found in the Lower Triassic of China, and these forms may also be ancestral to the stahleckeriids. The only other Triassic dicynodonts, Shansiodon and ‘ Dicynodon’ njalilus , may be placed in a separate family, the Shansiodontidae. All these Triassic genera have two features in common: the presence of a separately ossified olecranon process on the ulna, and a shortened interpterygoid vacuity. It is possible that this may indicate a common ancestry for them all, but no Upper Permian or Basal Triassic genera now known appear to be possible ancestors for them. The lack of any Middle Triassic vertebrate fauna in the northern hemisphere makes it very difficult to date the Argentinian and Brazilian faunas, which include gomphodont cynodonts, dicynodonts, rhynchosaurs, pseudosuchians and a few saurischians. It is not felt that the presence of rhynchosaurs necessarily indicates a Middle Triassic age, as the group is known from the mid-Norian of India. It is possible that the presence of several saurischians and of a pseudosuchian closely related to the German Norian genus Aëtosaurus , may indicate a Carnian age for the Argentine fauna. The Brazilian fauna is somewhat dissimilar to that of Argentina and contains no genera in common with it; it may therefore be of earlier, Ladinian, age. The fauna of the Manda Beds of East Africa is similar in composition to that of Brazil, but contains no genera in common with it. It also lacks saurischians and includes a dicynodont, Kannemeyeria , that is otherwise typical of the Lower Triassic Cynognathus zone of South Africa. It may therefore be Anisian in age.

Ichthyosaurs (Reptilia, Ichthyosauria) from the Lower and Middle Triassic Sulphur Mountain Formation, Wapiti Lake area, British Columbia, Canada

1989 ◽  
Vol 26 (7) ◽  
pp. 1491-1500 ◽  
Author(s):  
Jack M. Callaway ◽  
Donald B. Brinkman
Keyword(s):  
British Columbia ◽  
North America ◽  
Middle Triassic ◽  
Lower Triassic ◽  
Early Triassic ◽  
Lake Area ◽  
New Information ◽  
The Family

Ichthyosaurs are found in the Lower and Middle Triassic members of the Sulphur Mountain Formation in the Wapiti Lake area, British Columbia. Three species are recognized: Pessosaurus sp. in the family Shastasauridae from the Middle Triassic, Mixosaurus cf. M. nordenskioeldii in the family Mixosauridae from the Lower and Middle Triassic, and Phalarodon cf. P. fraasi in the family Omphalosauridae from the Middle Triassic. Other ichthyosaur material in the Lower Triassic (Smithian) member is the oldest known from North America and coeval with the oldest known elsewhere but cannot be identified confidently at this time. This material provides new information relative to the paleobiogeography of early ichthyosaurs and additional confirmation that ichthyosaurs were already highly specialized and quite diverse by the Early Triassic.

Lectotypification of Sematophyllum latifolium, a new synonym of Wijkia surcularis (Pylaisiadelphaceae, Bryophyta)

Phytotaxa ◽  
2021 ◽  
Vol 484 (3) ◽  
pp. 298-300
Author(s):  
NARIN PRINTARAKUL ◽  
SAHUT CHANTANAORRAPINT
Keyword(s):  
Type Specimen ◽  
Common Species ◽  
Type Material ◽  
Type Collection ◽  
Type Specimens ◽  
Northern Thailand ◽  
New Synonym ◽  
The Family

Sematophyllum latifolium Brotherus (1911: 362), known only from the type collection, was originally described by Brotherus (1911) based on a collection made by C.C. Hosseus from Mt. Doi Suthep (Doi Sutäp), in northern Thailand. Pollawatn (2008) revised the family Sematophyllaceae s.l. in Thailand but did not see the type specimen of S. latifolium. During the study of Hosseus’s collections, however, we found two duplicates of type specimens of S. latifolium one located in H-BR and one in M. We found that several critical features of S. latifolium, such as the 1) irregular-pinnately branching habit with the erect flagelliform branches (Fig. 1A), 2) stem and branch leaves strongly differentiated (Fig. 1B−F), and 3) brotherelloid type alar cells often divided into larger hyaline cells towards leaf margins (Fig. 1G), were indistinguishable from those in the type material of Wijkia surcularis (Mitten 1859: 112) Crum (1971: 173), a common species found growing from India to Indochina (Gangulee 1980; Tan & Iwatsuki 1993; Tan & Jia 1999; Jia et al. 2005). Thus, we here propose S. latifolium as a new synonym of W. sucularis. In the protologue, Brotherus (1911) did not designate the holotype, therefore, it is necessary to select a lectotype for S. latifolium ((see Art. 9.11 of the Shenzhen Code (Turland et al. 2017)). We designate Hosseus’s collection (Hosseus s.n.) in H-BR (H) as the lectotype of the name S. latifolium.

The oldest Diptera (Insecta) from the Upper Buntsandstein (early Middle Triassic) of Europe

Zootaxa ◽  
2021 ◽  
Vol 5067 (1) ◽  
pp. 135-143
Author(s):  
ELENA D. LUKASHEVICH
Keyword(s):  
Fossil Record ◽  
New Genus ◽  
Middle Triassic ◽  
Insect Fauna ◽  
The Family ◽  
Lower Franconia ◽  
Grès À Voltzia ◽  
Early Middle Triassic

The fossil record of Triassic Diptera is still poor, with the oldest dipteran assemblage described from the Upper Buntsandstein of the ‘Grès à Voltzia’ Formation (early Anisian, France). From the stratigraphically closest insect fauna of the Röt Formation of Lower Franconia, Germany, the first Diptera, Bashkonia franconica gen. et sp. nov. is described based on an isolated wing. The new genus is assigned to the family Nadipteridae, bridging the gap between two other genera included.  

A new genus of ichthyosaur from the Late Triassic Pardonet Formation of British Columbia: bridging the Triassic Jurassic gap

2001 ◽  
Vol 38 (6) ◽  
pp. 983-1002 ◽  
Author(s):  
Elizabeth L Nicholls ◽  
Makoto Manabe
Keyword(s):  
British Columbia ◽  
Type Species ◽  
New Genus ◽  
Late Triassic ◽  
Unique Combination ◽  
Type Specimens ◽  
Nomen Dubium ◽  
The Family ◽  
Large Diamond

Both the genus Shastasaurus and the family Shastasauridae have long been hard to define due to the fragmentary nature of the type specimens. Consequently, recent interpretations of the genus have been based almost entirely on Shastasaurus neoscapularis from the Late Triassic Pardonet Formation of British Columbia. Two new specimens of this taxon, from Pink Mountain, British Columbia, demonstrate that it does not belong in the genus Shastasaurus. This paper describes the new specimens, and refers the species to Metashastasaurus gen nov. Post-cranially, the skeleton of Metashastasaurus resembles that of shastasaurids, differing primarily only in the shape of the scapula and fibula. However, the skull has a unique combination of characters, including large diamond-shaped frontals that enter the supratemporal fenestrae, and very narrow posterior extensions of the nasals, which contact the postfrontals. It also differs from the skull of Shastasaurus in the presence of both a parietal ridge and postparietal shelf. This is a combination of derived characters previously known only in Jurassic forms. The front limb has four proximal carpals and four digits, indicating that previous reconstructions were based on incomplete material. Shastasaurus pacificus Merriam 1895, the type species of the genus Shastasaurus, must be considered a nomen dubium, making the genus Shastasaurus invalid. Until this problem is clarified, the use of the generic name Shastasaurus should be restricted to Merriam's type specimens, of which only Shastasaurus alexandrae and Shastasaurus osmonti are based on adequate material.

Heterochrony in Haplomesus (Crustacea: Isopoda: Ischnomesidae): revision of two species and description of two new species

Zootaxa ◽  
2006 ◽  
Vol 1120 (1) ◽  
pp. 1 ◽  
Author(s):  
FIONA A. KAVANAGH ◽  
GEORGE D.F. WILSON ◽  
ANNE M. POWER
Keyword(s):  
New Species ◽  
Original Description ◽  
Type Specimen ◽  
Type Material ◽  
Adult Type ◽  
The Family ◽  
Two New Species ◽  
Argentine Basin

Two new species of Ischnomesidae, Haplomesus celticensis sp. nov. and Haplomesus hanseni sp. nov. are described from the southwest of Ireland and the Argentine Basin respectively. Both species lack the expression of pereopod VII, a characteristic that we argue is produced by progenesis, not neoteny as suggested by Brökeland & Brandt (2004). Haplomesus angustus Hansen, 1916 and Haplomesus tropicalis Menzies, 1962, also lack pereopod VII and are revised from the type material. The original description of Haplomesus angustus Hansen, 1916 describes the adult type specimen as a juvenile; the original description of Haplomesus tropicalis Menzies, 1962 fails to mention the lack of pereopod VII. Progenesis is discussed for the above species and within the family Ischnomesidae as a whole.

On the presence ofMixosaurus(Ichthyopterygia: Reptilia) in the Middle Triassic of Nevada

1990 ◽  
Vol 64 (1) ◽  
pp. 161-164 ◽  
Author(s):  
P. Martin Sander ◽  
Hugo Bucher
Keyword(s):  
British Columbia ◽  
North America ◽  
Middle Triassic ◽  
Lower Triassic ◽  
High Arctic ◽  
Western Tethys ◽  
History Of ◽  
Northwestern North America

The small ichthyosaurMixosaurusis the most widely distributed ichthyosaur. It is known from Lower Triassic rocks of British Columbia, Canada (Callaway and Brinkman, 1989), and Middle Triassic rocks of northwestern North America (Alaska, British Columbia), China, Timor, the western Tethys (Switzerland, Italy, Turkey), the Germanic Triassic, and the high Arctic (Spitsbergen, Exmouth Island) (Mazin, 1986; Callaway and Brinkman, 1989; Callaway and Massare, 1989). The presence ofMixosaurusin one of the richest ichthyosaur provinces, the Middle Triassic of Nevada (Merriam, 1908), has been difficult to establish. The history of this problem is very colorful and is the topic of this note together with the description of a new specimen from the Nevada Middle Triassic.

Taphonomic bias and the evolutionary history of the family Cidaridae (Echinodermata: Echinoidea)

Paleobiology ◽  
1992 ◽  
Vol 18 (1) ◽  
pp. 50-79 ◽  
Author(s):  
Benjamin J. Greenstein
Keyword(s):  
Type Species ◽  
Evolutionary History ◽  
Middle Triassic ◽  
Upper Jurassic ◽  
Late Triassic ◽  
Type Specimens ◽  
Fossil Material ◽  
Group I ◽  
The Family ◽  
History Of

The class Echinoidea apparently originated during the Ordovician Period and diversified slowly through the Paleozoic Era. The clade then mushroomed in diversity beginning in Late Triassic time and continued expanding into the present. Although this evolutionary history is generally accepted, the taphonomic overprint affecting it has not been explored. To gain a more accurate perception of the evolutionary history of the group, I have compared the diversity history of the family Cidaridae (Echinodermata: Echinoidea) with the preservational style of fossil type species using literature-derived data. The Cidaridae apparently originated in Middle Triassic time and diversified slowly through the Neocomian (Early Cretaceous). Diversity was maintained through the remainder of the Cretaceous and Tertiary Periods, reflecting the diversity history of the subclass. Characterization of the preservational style of type fossil material for the family revealed the following breakdown of preservational states: 60% of species were described on the basis of disarticulated skeletal material, primarily spines; 20% based on intact coronas denuded of spines, apical system, Aristotle's lantern and peristomial plates; 10% based on large coronal fragments; and 10% based on other skeletal elements. This distribution may represent the effect of a disarticulation threshold on the condition of echinoid carcasses before final burial and suggests that preservation of intact specimens may be very unlikely. For cidaroids, previous work has suggested that this threshold is likely to be reached after 7 days of decay.Comparison of the diversity history of the Cidaridae with the preservation data reveals that characteristic patterns of taphonomic overprint have affected the group since its origination in Middle Triassic time, and the nature of that overprint has changed over time: the early diversity history of the group is characterized by occurrences of fragmented fossil material, with spines predominant; further radiation of the group in mid-Jurassic time coincided with an increase in modes of preservation, ranging between exceptionally well-preserved material and disarticulated skeletal elements. Finally, type material is more rarely described from younger stratigraphic intervals (Miocene–Pleistocene) and consists predominantly of disarticulated skeletal elements and coronal fragments larger than an interambulacrum in size. Intact, denuded coronas are noticeably lacking.The number of type species of Cidaridae described in each stratigraphic interval has not been consistent during post-Paleozoic time. Middle Triassic, Malm (Upper Jurassic), Senonian (Upper Cretaceous) and Eocene series yielded significantly (α = .05) higher numbers of type specimens per million years, while the Lias (Lower Jurassic), Dogger (Mid-Jurassic), Lower Cretaceous and Paleocene yielded significantly (α = .05) lower numbers of type specimens per million years. This may be the result of a combination of taxonomic, sampling, and geographical biases.

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