| Basic info | Taxonomic history | Classification | Included Taxa |
| Morphology | Ecology and taphonomy | External Literature Search | Age range and collections |
Taxonomy
Trinitichelys maini was named by Adrian et al. (2019). Its type specimen is DMNH 2013-07-0712, a partial shell (anterior lobe of a plastron), and it is a 3D body fossil. Its type locality is Arlington Archosaur Site (facies A), which is in a Cenomanian delta plain siltstone/siltstone in the Lewisville Formation of Texas.
It was recombined as Gehennachelys maini by Adrian et al. (2023).
It was recombined as Gehennachelys maini by Adrian et al. (2023).
Synonymy list
| Year | Name and author |
|---|---|
| 2019 | Trinitichelys maini Adrian et al. |
| 2023 | Gehennachelys maini Adrian et al. |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Gehennachelys maini Adrian et al. 2019
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| B. Adrian et al. 2019 | Basal baenid, as indicated by similarly-sized Gu and Ex, a mostly co-ossified shell, and robust bridge peripherals. Tentatively included in “Trinitichelys” based on shared paired intergular scutes, absent fenestra, and a rectangular cervical scute. Medial contact of Ex differentiates this taxon from T. hiatti and Neurankylus. This character alone differentiates the AAS baenid from the limited material known for T. hiatti. However, additional shell, cranial, and postcranial material is currently being prepared and new diagnostic characters will warrant either the erection of a new genus or more definitive inclusion in Trinitichelys. “Trinitichelys” maini sp. nov. is thus placed in “Trinitichelys” as a derived turtle relative to T. hiatti, but lacks the set of derived characters that diagnose Baenodda. No midline contact of the Ex is the derived condition found in Plesiobaena, Palatobaena, Stygiochelys, Baena, and Chisternon. Ex-Gu sulci curved, unlike Dinochelys, T. hiatti, N. baueri, and N. lithographicus. It is also diagnosed by its lack of epiplastral processes and a single undivided Ce that is taller than wide, as in T. hiatti, N. eximius, and N. notos. Fenestrae absent, as in T. hiatti, N. eximius, Boremys, and P. brinkman, but unlike Plesiobaena antiqua and Palatobaena cohen (Joyce and Lyson, 2015). It has a femoro-anal sulcus that is relatively straight, rather than omega-shaped, which is found in more derived baenodds (Joyce and Lyson, 2015; Lyson et al., 2016). | |
| B. Adrian et al. 2023 | The newly combined taxon is diagnosed by the following unique combination of characters, rather than particular autapomorphies: deep upper temporal emargination exposing the anterior margin of the otic chamber in dorsal view; absent parietal-squamosal contact; elongated squamosal processes; prominent crista supraoccipitalis that is not covered anteriorly by the parietals; shell co-ossified in adults, with robust bridge peripherals and absent fenestrae; gular and extragular scales paired and similarly sized, with midline extragular contact; curved gular-extragular sulci; single, undivided cervical scale that is wider than long; straight femoral-anal sulcus; a complete ring of 12 marginal scales that separate the posteriormost vertebral scale from the carapace margin; scalloped posterior carapace margin; anterior and posterior plastral lobes that are approximately equidimensional. |
Measurements
No measurements are available
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| Source: c = class, subp = subphylum, uc = unranked clade | |||||
| References: Hendy et al. 2009, Carroll 1988 | |||||
Age range: Middle Cenomanian or 99.60000 to 93.50000 Ma
Collections: one only
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Middle Cenomanian | USA (Texas) | Trinitichelys maini (type locality: 172153) |