A new long-headed dipnoan (Osteichthyes) from the middle Devonian of Iowa, USA

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Abstract
The new genus and species Iowadipterus halli is described from the Middle Devonian of Iowa, U.S.A. Iowadipterus is a long-headed but not long-snouted dipnoan with many distinct features: cheek bones 8 and 9 enlarged, bone 8 bordering bones Y1 and Y2 so that only bones Y2 and Z lie dorsal to the operculum; cheek pit line passing from bone 8 directly to bone 9; elongation of B- and C-bones without differentiation of D- or E-bones; narrow submandibular combined with broad gulars; and scales with tubercles with a shallow depression on the overlapped part of scale. Iowadipterus and possibly Holodipterus are long-headed dipnoans with a short lower jaw, in contrast to long-headed forms with a long snout (Griphognathus, Soederberghia, Rhynchodipterus, and Fleurantia with elongated rami, and Rhinodipterus with an elongated symphysis). The broad cheek offers a wide space for the adductor muscles and indicates a powerful bite.