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Brachaucheninae
Taxonomy
Brachaucheniidae was named by Williston (1925). Its type is Brachauchenius.
It was synonymized subjectively with Polycotylidae by Persson (1963); it was reranked as the subfamily Brachaucheninae by Benson and Druckenmiller (2014), Páramo-Fonseca et al. (2018), Zverkov and Pervushov (2020) and Páramo-Fonseca et al. (2023).
It was assigned to Plesiosauria by Hay (1930); to Pliosauroidea by Kuhn (1966) and Carpenter (1996); to Pliosauridae by Páramo-Fonseca et al. (2018); and to Thalassophonea by Benson and Druckenmiller (2014), Zverkov and Pervushov (2020) and Páramo-Fonseca et al. (2023).
It was synonymized subjectively with Polycotylidae by Persson (1963); it was reranked as the subfamily Brachaucheninae by Benson and Druckenmiller (2014), Páramo-Fonseca et al. (2018), Zverkov and Pervushov (2020) and Páramo-Fonseca et al. (2023).
It was assigned to Plesiosauria by Hay (1930); to Pliosauroidea by Kuhn (1966) and Carpenter (1996); to Pliosauridae by Páramo-Fonseca et al. (2018); and to Thalassophonea by Benson and Druckenmiller (2014), Zverkov and Pervushov (2020) and Páramo-Fonseca et al. (2023).
Subtaxa
Synonymy list
| Year | Name and author |
|---|---|
| 1925 | Brachaucheniidae Williston |
| 1930 | Brachaucheniidae Hay p. 119 |
| 1966 | Brachaucheniidae Kuhn p. 116 |
| 1996 | Brachaucheniidae Carpenter p. 261 |
| 2014 | Brachaucheninae Benson and Druckenmiller figs. 2-3 |
| 2018 | Brachaucheninae Páramo-Fonseca et al. |
| 2020 | Brachaucheninae Zverkov and Pervushov |
| 2023 | Brachaucheninae Páramo-Fonseca et al. p. 2 |
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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.
Subfm. †Brachaucheninae Williston 1925
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G. †Discosaurus Leidy 1851
G. †Kronosaurus Longman 1924
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†Kronosaurus boyacensis Hampe 1992
†Kronosaurus queenslandicus Longman 1924
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| R. B. J. Benson and P. S. Druckenmiller 2014 | Thalassophonean pliosaurids with the following unique, unambiguous synapomorphies: entire posteromedial extension of the maxilla extends far posteromedial to the external naris (29.2; a medial part of the posteromedial extension of the maxilla also extends far posteriorly in a specimen of Pliosaurus [BRSMG Cc332; Ketchum & Benson, 2010, fig. A1), postorbital-squamosal contact absent, so jugal participates in margin of temporal fenestra (42.1), foramina subcentralia on ventral surfaces of cervical vertebrae reduced in size or absent (156.2), cervical rib facets located around midheight of centrum or more dorsally, contacting neural arch peduncles (162.1).
Brachaucheninines also possess several unambiguous synapomorphies that represent reversals from the primitive condition in some or all other thalassophoneans: absence of a transverse constriction of the rostrum (1.0), mandibular glenoid just posterior to occipital condyle (10.1), alveolar margin of upper jaw in lateral view not scalloped (=sinuous) (13.0), frontal does not participate in external naris (31.0), medial portion of squamosal arch with anteroposteriorly broad cross section (54.0), symphysial portion of mandible notmediolaterally expanded (113.0), homodont premaxillary (132.0) and maxillary (133.0) dentitions, dorsal neural arches dorsoventrally tall, bases of transverse processes dorsal to the level of the neural canal (181.0). Finally, a number of non-unique, unambiguous synapomorphies are present: an elongated rostrum comprising greater than 0.56 of the total skull length, partly due to reduction of the length of the temporal region (4.2; a similarly large proportion is present in Hauffiosaurus, Archaeonectrus rostratus, and some polycotylids), prefrontal participates in external naris (35.1), anterior extent of squamosal lies significantly posterior to the postorbital bar (57.1; also present in some rhomaleosaurids, elasmosaurids and microcleidids), parasphenoid posterior extent on the midline lies just anterior to the basioccipital-basisphenoid contact, so this contact is exposed in ventral view (84.1; also present in many non-xenopsarian plesisoauroids), pterygoids contact on midline immediately anterior to posterior interpterygoid vacuity, so the cultriform process of the parasphenoid is not visible in ventral view of this location (86.0; also present in Meyerasaurus victor; reversed from the condition in Plesiosauria, in which the cultriform process is visible), retroarticular process of mandible inflected slightly posteromedially (123.1; also present in some leptocleidids), cervical ribs with reduced anterior process, and long axis uniting anterior and posterior processes is oriented posteroventrally (163.1; also present in Plesiopterys wildi and cryptoclidians other than Elasmosauridae). |