Lonchodraco machaerorhynchus, Rodrigues & Kellner, 2013

Rodrigues, Taissa & Kellner, Alexander Wilhelm Armin, 2013, Taxonomic review of the Ornithocheirus complex (Pterosauria) from the Cretaceous of England, ZooKeys 308, pp. 1-112 : 18-19

Lonchodraco machaerorhynchus comb. n. Fig. 5

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

Ornithocheirus machaerorhynvhus Seeley: Seeley 1870: p. 113, pl. XII, fig. 1-2

Lonchodectes machaeorhynchus [sic] (Seeley): Hooley 1914: p. 535

Lonchodectes machaerorhynchus (Seeley): Unwin 2001: p. 195, fig. 12D-E, table 1

Holotype:

CAMSM B54855, partial mandibular symphysis ( Fig. 5A-F ).

Type locality.

Cambridge, Cambridgeshire, England.

Type horizon.

Cambridge Greensand (Cenomanian; fossils Albian in age).

Diagnosis.

Lonchodraconid pterosaur with the following combination of characters that distinguishes it from other members of the clade (autapomorphies are marked with an asterisk): deep dentary crest*; ventral margin of the mandible posterior to the dentary crest ascending in lateral view*; ventral depression located posteriorly to the dentary crest*; wide mandibular groove*; approximately 4.5 alveoli per 3 cm of jaw margin.

Description.

CAMSM B54855 consists of a fragment of the posterior portion of the mandibular symphysis. Seeley (1870) described the mandible as narrow, with parallel alveolar margins, deep mandibular sulcus, spacing between alveoli equal to the size of their diameters, and with the lateral margins forming a sharp keel, which Unwin (2001) interpreted as a dentary crest. Seeley (1870) mentioned the presence of a suture with the angular bone, which would almost reach the tip of the mandible, as a unique character for this species in comparison to the pterosaurs from Germany. We here interpret this structure as the posterior margin of a dentary crest rather than a suture.

In addition to a deep mandibular groove, CAMSM B54855 shares with Lonchodraco giganteus small and well-spaced alveoli, without significant size variation. However, it differs from this species in having straight alveolar margins in dorsal view ( Seeley 1870), whereas the margins diverge in Lonchodraco giganteus . The mandibular crest of Lonchodraco machaerorhynchus is deep and its apex coincident with its terminus, with a ventral depression posterior to it. In Lonchodraco giganteus , the mandibular crest is short and blade-like, being more restricted to the length of the symphysis; the presence of a depression cannot be determined.

Figures

Figure 5. Lonchodraco machaerorhynchus comb. n. Holotype CAMSM B 54855 (Albian, Cambridge Greensand), fragment of the mandibular symphysis A right lateral view B respective line drawing C dorsal view D respective line drawing E ventral view F respective line drawing. Abbreviations: d - dentary, dcr - dentary crest, sul - sulcus. Arrows indicate alveoli or teeth. Scale bar = 10 mm.