Gracilineustes, Young & Brusatte & Ruta & Andrade, 2010

Young, Mark T., Brusatte, Stephen L., Ruta, Marcello & Andrade, Marco Brandalise De, 2010, The evolution of Metriorhynchoidea (mesoeucrocodylia, thalattosuchia): an integrated approach using geometric morphometrics, analysis of disparity, and biomechanics, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 158 (4), pp. 801-859 : 850

GRACILINEUSTES GEN. NOV.

Type species: Gracilineustes leedsi (Andrews, 1913) comb. nov.

Valid species: Gracilineustes acutus (Lennier, 1887) comb. nov.; Gr. leedsi (Andrews, 1913) comb. nov.

Etymology: ‘Gracile swimmer’. In reference to the slender nature of both their longirostrine crania and postcrania in comparison with other Callovian forms.

Geological range: Middle Callovian–upper Kimmeridgian.

Geographical range: European endemic ( England, France, and Switzerland).

Diagnosis: Metriorhynchid thalattosuchian with over 28 teeth per maxilla, and more than 20 teeth per dentary; lacking conspicuous ornamentation on the cranial bones; the antorbital fossa is elongate, narrow, and oriented obliquely, and is enclosed by the lacrimal, maxilla, and jugal; the antorbital pseudofenestra is enclosed by the lacrimal, nasal, and maxilla; the internal nares opens out posteriorly into the buccal cavity, with the palatines creating a broad U-shape, directed anteriorly; the maxilla–palatine suture forms an M-shape, orientated posteriorly; the squamosal contributes less than 50% to the supratemporal arch; the squamosal projects further caudally than the occipital condyle; the mandibular symphysis depth is ~4% of the total mandible length; the length of the cervical centrum is shorter than its height; the tibia is roughly one third of the length of the femur; the atlas hypocentrum is subequal in length to the odontoid process length; the humerus is smaller in length than the scapula; the ischium anterior process lacks either articulation facet.