A new early Late Triassic non-mammaliaform eucynodont from Poland

Sulej, Tomasz; Niedźwiedzki, Grzegorz; Tałanda, Mateusz; Dróżdż, Dawid; Hara, Ewa

doi:10.1080/08912963.2018.1471477

Cited by 12 publications

(18 citation statements)

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“…2004 ; Sulej et al . 2020). Therefore, it is likely that genuine declines in diversity, a trend towards smaller body size, and a change in collection techniques, all contribute to the Late Triassic decline in cynodont completeness.…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal variation in completeness of the early cynodont fossil record and its implications for mammalian evolutionary history

2021

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Mammals are the only surviving group of Cynodontia, a synapsid clade that first appeared in the fossil record in the late Permian, ~260 million years ago. Using three metrics that capture skeletal completeness, we quantify the quality of the early cynodont fossil record in time and space to evaluate the impact of sampling and preservational biases on our understanding of the group's evolutionary history. There is no consistent global sampling signal for early cynodonts. Completeness of the cynodont fossil record increases across the Permian–Triassic boundary, peaking in the Early to early Late Triassic. This peak is dominated by specimens from southern Africa and South America, where a highly seasonal climate probably favoured preservation. Completeness is generally lower thereafter, correlating with a shift from a Gondwanan to a predominantly Laurasian fossil record. Phylogenetic and stratigraphic congruence in early cynodonts is high, although their fossil record exhibits less skeletal completeness overall than other tetrapod clades, including the contemporaneous anomodont synapsids. This discrepancy could be due to differences in the diagnosability of their fossils, especially for small‐bodied species. Establishing the timing and assembly of derived (‘mammalian’) anatomical features in Cynodontia is obscured by sampling. Two of the major nodes at which acquisition of mammalian features is concentrated (Cynodontia and Mammaliamorpha) suffer from lengthy intervals of poor sampling before becoming abundant parts of tetrapod faunas. Low completeness in these intervals limits our ability to determine when certain ‘key’ mammalian characteristics evolved, or to identify the selective pressures that might have driven their origins.

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Section: Discussionmentioning

confidence: 99%

Spatiotemporal variation in completeness of the early cynodont fossil record and its implications for mammalian evolutionary history

2021

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“…All the specimens are housed in the Vertebrate Paleontology Laboratory of the Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, India. The Tiki specimens are compared with the teeth of other valid non-mammalian cynodonts such as Dromatherium (Emmons, 1857), Microconodon (Osborn, 1886; Simpson, 1926a; Sues, 2001; Heckert et al, 2012), Pseudotriconodon (Hahn et al, 1984), Gaumia (Hahn et al, 1987), Tricuspes (Godefroit and Battail, 1997), Meurthodon (Sigogneau-Russell and Hahn, 1994), Hahnia (Godefroit and Battail, 1997), and Rewaconodon (Datta et al, 2004), and the Late Triassic and Early Jurassic morganucodontids Eozostrodon (Parrington, 1941), Morganucodon (Kühne, 1949), Erythrotherium (Crompton, 1964), Helvetiodon (Clemens, 1980), Hallautherium (Clemens, 1980), Gondwanadon (Datta and Das, 1996), Rosierodon (Debuysschere et al, 2015), and Polonodon (Sulej et al, 2020).…”

Section: Methodsmentioning

confidence: 99%

“…The evolution of mammal-like features in non-mammalian cynodonts and early mammals is debated extensively (Zhou et al, 2013; Świło et al, 2014; O'Meara and Asher, 2016; Luo et al, 2017; Huttenlocker et al, 2018; Krause et al, 2020). One of the key features was the subdivision of the single-rooted postcanines into double-rooted premolars and multi-rooted molars (Rowe, 1988; Luo, 1994; Lucas et al, 2001; Shapiro and Jenkins, 2001; Sulej et al, 2020). Cynodonts experienced their first phase of diversification just before the end of the Permian.…”

Section: Introductionmentioning

confidence: 99%

“…Other Gondwanan records are from southern Brazil (Martinelli et al, 2005, 2016, 2017; Soares et al, 2014), Argentina (Martinelli et al, 2016; Fiorelli et al, 2018), South Africa (Sidor and Hancox, 2006), and India (Chatterjee, 1982; Datta et al, 2004; Ray, 2015). Non-mammalian cynodonts are also known from the Late Triassic of Laurasian landmasses, which in today's geography include such regions and countries as Greenland (Shapiro and Jenkins, 2001), the United States (Lucas and Oakes, 1988; Sues et al, 1994; Liu and Olsen, 2010; Liu and Sues, 2010; Heckert et al, 2012), Germany (Lucas et al, 2001), Poland (Świło et al, 2014; Sulej et al, 2020), and several continental European countries.…”

Section: Introductionmentioning

confidence: 99%

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New cynodonts (Therapsida, Eucynodontia) from the Late Triassic of India and their significances

Bhat

Ray

Datta³

2020

J. Paleontol.

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The Upper Triassic Tiki Formation of India has yielded several new cynodont taxa, which are described on the basis of multiple isolated teeth and a jaw fragment. A new species of dromatheriid, Rewaconodon indicus, is defined by a tri- and tetracuspid asymmetric crown, long anterior edge of the major cusp a, cingular cusps d and f, and marked constriction at the crown-root junction. Another new dromatheriid, Inditherium floris n. gen. n. sp., is characterized by a broad, flower-shaped pentacuspid crown, multiple cingular cusps, and a weak lingual cingulum is also described from the same horizon. In addition, a new mammaliamorph taxon, Tikiodon cromptoni n. gen. n. sp., is established on a tooth specimen, which has a shovel-shaped crown, three closely spaced main cusps, a pronounced lingual cingulum with multiple cingular cusps, and a root of incomplete root bifurcation. Such a tooth morphology occupies an intermediate position between the non-mammalian cynodonts and the early mammals, as is evident from the co-occurrence of various cynodont dental morphotypes in the Tiki Formation. Moreover, Late Triassic cynodonts occurred along narrow belts demarcated by paleolatitudes, though the Indian fauna shows both Laurasian and Gondwanan affinities. UUID: http://zoobank.org/c2c575ad-ee23-4f33-8a30-661c548a5b17

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“…2004) and Polonodon woznikiensis (Sulej et al . 2018) from the lower Upper Triassic of the United States, India and Poland, respectively. Considering this ‘dromatheriid’ resemblance and the differentiation made by Datta et al .…”

Section: Review Of the Ksar Metlili Faunamentioning

confidence: 99%

New data on the microvertebrate fauna from the Upper Jurassic or lowest Cretaceous of Ksar Metlili (Anoual Syncline, eastern Morocco)

et al. 2019

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The Middle Jurassic – Early Cretaceous period witnessed the emergence of some major representatives of modern continental vertebrate groups (stem lissamphibians, squamates, therian mammals and birds) and angiosperms, at a time when fragmentation of Pangaea was underway. The successive Moroccan microvertebrate faunas of Ksar Metlili (?Berriasian) and Guelb el Ahmar (Bathonian) from the Anoual Syncline significantly improve our poor knowledge of Gondwanan and especially African palaeobiodiversity at this time. They are among the richest known from the Mesozoic of Gondwana, and are well placed in northwestern Africa to record faunal interchanges with Laurasia. Here we focus on the Ksar Metlili fauna, first documented in the 1980s and most recently resampled in 2010, which produced 24 541 microremains representing 47 species of 8 main groups (Chondrichthyes, Actinopterygii, Sarcopterygii, Lissamphibia, Lepidosauromorpha, Testudinata, Archosauromorpha and Synapsida). It includes remarkable taxa: the oldest stem boreosphenidan mammals from Gondwana, probably some of the last non-mammaliaform cynodonts, a basal ornithischian, possibly freshwater teleosaurid crocodylomorphs, and some of the rare occurrences of choristoderes and albanerpetontids in Gondwana. Comparison of the Ksar Metlili fauna with that of Guimarota (Kimmeridgian, Portugal) further provides evidence of numerous shared taxa of Laurasian affinities, in contrast to the occurrence of few taxa with Gondwanan affinities. This suggests complex palaeobiogeographical relationships – implying both vicariance and dispersal events – of North Africa within Gondwana at the Jurassic–Cretaceous transition. Finally, the faunal similarities with the Guelb el Ahmar fauna question the Cretaceous age of the Ksar Metlili fauna, suggesting an alternative possible Late Jurassic age.

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A new early Late Triassic non-mammaliaform eucynodont from Poland

Cited by 12 publications

References 46 publications

Spatiotemporal variation in completeness of the early cynodont fossil record and its implications for mammalian evolutionary history

Spatiotemporal variation in completeness of the early cynodont fossil record and its implications for mammalian evolutionary history

New cynodonts (Therapsida, Eucynodontia) from the Late Triassic of India and their significances

New data on the microvertebrate fauna from the Upper Jurassic or lowest Cretaceous of Ksar Metlili (Anoual Syncline, eastern Morocco)

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