Ornithocheirus polyodon, Seeley, 1870

Rodrigues, Taissa & Kellner, Alexander Wilhelm Armin, 2013, Taxonomic review of the Ornithocheirus complex (Pterosauria) from the Cretaceous of England, ZooKeys 308, pp. 1-112 : 33-34

' Ornithocheirus ' polyodon Seeley, 1870 Fig. 12A-D

"Ptenodactylus" polyodon Seeley: Seeley 1869: p. xvi [disclaimed]

Ornithocheirus polyodon Seeley: Seeley 1870: p. 121

Ornithocheirus polyodon Seeley: Hooley 1914: p. 535

Anhanguera fittoni (Owen): Unwin 2001: table 1 [synonymy]

Holotype.

CAMSM B54440, anterior portion of the rostrum ( Fig. 12A-D ).

Type locality.

Cambridge, Cambridgeshire, England.

Type horizon.

Cambridge Greensand (Cenomanian; fossils Albian in age).

Diagnosis.

Pterodactyloid pterosaur with the following combination of characters that distinguishes it from other members of the clade (autapomorphies are marked with an asterisk): premaxillary crest absent; anterior expansion absent; palate dorsally curved; moderately developed palatal ridge; palate between the elevated alveolar rims and the palatal ridge concave; palatal ridge extending anteriorly up to the second pair of alveoli; alveoli ventrolaterally oriented; spacing between alveoli less than their diameters; approximately 5.5 alveoli per 3 cm of jaw margin*.

Description.

Seeley (1870) founded 'Ornithocheirus' polyodon upon a fragmentary rostrum. He pointed out that CAMSM B54440 possesses a moderate palatal ridge, dorsally curved palate, first pair of alveoli facing forwards, more posterior alveoli facing more laterally than ventrally, and small spacing between the alveoli. He cited the last feature as the main difference between 'Ornithocheirus' polyodon and Pterodactylus fittoni , thus justifying the creation of a new species.

' Ornithocheirus' polyodon can be excluded from Ornithocheirus because it lacks a tall rostrum. It cannot be referred to Cimoliopterus because the alveolar spacing is quite distinct; in Cimoliopterus cuvieri , only the first three pairs of alveoli are more closely positioned. It can also be excluded from Camposipterus because it lacks an anterior expansion of the rostrum.

'Ornithocheirus' polyodon shares with Lonchodraconidae the presence of small alveoli at the tip of the rostrum, which do not vary significantly in size. However, it differs from members of this clade in lacking an elevated alveolar margin or a prominent palatal ridge, as in Lonchodraco(?) microdon . However, it is possible that such elevation would get deeper posteriorly, but this cannot be confirmed in the holotype. Furthermore, the spacing between the alveoli being smaller than their diameters is not present in other lonchodraconids.

It is suggested here that 'Ornithocheirus' polyodon might represent a new genus. As the known material is quite incomplete, we refrain from naming this taxon at the present time and use its originally proposed binomen.

Figures

Figure 12. A-D ' Ornithocheirus' polyodon, holotype CAMSM B 54440 (Albian, Cambridge Greensand), anterior part of the rostrum. A right lateral view B respective line drawing C ventral view D respective line drawing. E-H ' Ornithocheirus' platystomus, holotype CAMSM B 54835 (Albian, Cambridge Greensand), anterior part of the rostrum E right lateral view F respective line drawing G ventral view H respective line drawing. Abbreviations: m - maxillae, pm - premaxillae, prid - palatal ridge. Arrows and numbers indicate alveoli or teeth and their respective position. Scale bar = 10 mm.