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| Beesiiwo cooowuse Fitch, Haas,C’Hair, Ridgley, Ridgley, Oldman, Reynolds & Lovelace, 2023 DOI: 10.3390/d15040544 artwork: Gabriel Ugueto twitter.com/SerpenIllus |
Abstract
New discoveries in the lower Popo Agie Formation (lower carbonate unit) of central Wyoming necessitated a reevaluation of USNM 494329 from the same unit, the only known hyperodapedontine rhynchosaur in western North America. Well known from Gondwanan deposits, hyperodapedontines appear to be restricted to the Carnian age (Late Triassic), with the exception of Teyumbaita in the earliest Norian age (Late Triassic) of Brazil. Initially assigned to c.f. ‘Hyperodapedon’ sanjuanensis, our phylogenetic analyses reject this hypothesis, in support of a sister relationship between USNM 494329 (Beesiiwo cooowuse, gen. et sp. nov.) and Oryctorhynchus bairdi forming an early-diverging clade that is only distantly related to ‘H.’ sanjuanensis. Five additional specimens recovered from the lower Popo Agie are described. Three are referred to B. cooowuse, and another two are placed closer to Hyperodapedon and the remainder of Hyperodapedontinae. Our analysis demonstrates potential temporal distinction between a grade of earliest-diverging hyperodapedontines (including all Wyoming taxa) and a exclusively Late Carnian, Southern Pangaean hyperodapedontine clade (including ‘H.’ sanjuanensis). We consider the lower Popo Agie Formation to represent the first nonmarine Late Triassic unit of Western North America that can be confidently restricted to the Carnian age.
Keywords: Popo Agie Formation; Late Triassic; rhynchosaur; Hyperodapedontinae; Carnian
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| (A) The type specimen for Beesiiwo cooowuse (USNM 494329); occlusal view (top left/center) and axial cross section (bottom left/center) of posterior maxilla, and occlusal view of dentary (top/bottom right). Note that the row of teeth medial to L1 and L2 is not M1, but a fragment of the dentary that remains slotted into the longitudinal groove of the maxilla. (B–D) Occlusal view of three left maxillae from Cottonwood Creek referred to Beesiiwo cooowuse. Note the presence of M1 and absence of any additional medial rows. All scale bars = 1 cm. Illustration CC by Jim Morrison. |
Systematic Paleontology
Sauria McCartney, 1802, sensu Gauthier et al., 1988
Archosauromorpha von Huene, 1946 sensu Dilkes, 1998
Rhynchosauridae Cope, 1871 sensu Dilkes, 1998
Hyperodapedontinae (Chatterjee, 1969 nom. trans. ex Lydekker, 1885 sensu Langer and Schultz, 2000)
Beesiiwo gen. nov.
Etymology: Beesiiwo, from Arapaho “Beesiiwó” (pronounced “ Bah - se - wa - ’ ”, with the apostrophe representing a glottal stop) meaning “big lizard”.
Pronunciation guide: The sound for b is roughly as in English, but more like b before other consonants or at the end of a word; the sound for ee is as in the English ‘bat’ but is held longer; the sound for s is like in English, but always a nonvocailized, never vocalized as in some English s and all English z sounds; the sound for ii is as in English ‘beat’ but held longer; the sound for o is as in English ‘hot; the sound for ‘ is a glottal stop, as in the middle of oh-oh! in English.
Beesiiwo cooowuse sp. nov.
Holotype: USNM 494329, fragment of a left maxilla and a left dentary.
Etymology: cooowuse, from Arapaho “ co’ oowu se’ ” (pronounced “ ja’ aw-wu sa’ ”, with the apostrophe representing a glottal stop); meaning the “Alcova area”, central WY.
Pronunciation guide: The sound for c is like that of the English j but without any puff of air and more like the English ch before other consonants or at the end of a word; the sound for oo is as in the English ‘got’ but held longer; the sound for w is like in English; the sound for u is as in the English ‘put’; the sound for e is as in English ‘bet’.
Occurrence: The type specimen was collected as clasts within a 0.5–1 m thick microconglomerate in the lower carbonate unit of the Popo Agie Formation near Hole in the Wall, Southern Bighorn Mountains, WY (‘Willow Creek’ of [22]). Referred material (see below) was collected as rounded to partially rounded clasts in a 0.5–2 m thick microconglomerate also referred to the lower carbonate unit of the Popo Agie Formation, Cottonwood Creek near Alcova, WY.
Diagnosis: Diagnosed by the following combination of character-states: maxilla with two lateral tooth rows and one medial tooth row; teeth of the lateral tooth row L1 lacking prominent anterolingual flanges; crest-shaped areas, respectively, medial and lateral to a longitudinal groove on the occlusal surface of the maxilla; dentary without a row of lingual teeth.
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| Life reconstruction of Beesiiwo cooowuse with Heptasuchus clarki in the background representing the known fauna from the lower carbonate unit of the Popo Agie Formation. artwork: Gabriel Ugueto twitter.com/SerpenIllus |
Adam J. Fitch, Merle Haas,Wayne C’Hair, Eugene Ridgley, Ben Ridgley, Devin Oldman, Crystal Reynolds and David M. Lovelace. 2023. A New Rhynchosaur Taxon from the Popo Agie Formation, WY: Implications for a Northern Pangean Early-Late Triassic (Carnian) Fauna. Diversity. 15(4), 544. DOI: 10.3390/d15040544
