Dakosaurus, VON QUENSTEDT, 1856

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 : 858-859

DAKOSAURUS VON QUENSTEDT, 1856

Dacosaurus Sauvage, 1873

Plesiosuchus Owen, 1884

Aggiosaurus Ambayrac, 1913

Type species: Dakosaurus maximus (Plieninger, 1846) von Quenstedt, 1856 .

Valid species: Dakosaurus andiniensis Vignaud & Gasparini, 1996 ; D. maximus (Plieninger, 1846) von Quenstedt, 1856 ; Dakosaurus manselii (Hulke, 1870) Woodward, 1885 ; Dakosaurus nicaeensis (Ambayrac, 1913) Young & Andrade, 2009 .

Potentially valid species: Dakosaurus lissocephalus Seeley, 1869 .

Putative species (1): Isolated Dakosaurus teeth have long been known from the lower Oxfordian of England (Lydekker, 1890b) and the Middle Oxfordian of Poland (Jentzsch, 1884; Gallinek, 1895). These teeth are far smaller and less robust than those from the upper Oxfordian onwards, and possibly represent a distinct species.

Putative species (2): The incomplete Dakosaurus cranial specimens known from the late lower Kimmeridgian/early upper Kimmeridgian of Mexico represent at least one distinct taxon (Buchy et al., 2007; Buchy, 2008a).

Putative species (3): A vertebrae and fifth metatarsal known from the upper Tithonian or lower Berriasian of Khoroshevskii Island, Volga Region, Russia, have been suggested to belong to Dakosaurus (Ochev, 1981) .

Teeth taxa: Most of the isolated teeth of Dakosaurus recovered in Europe have automatically been assigned to D. maximus (e.g. see Steel, 1973). However, as the phylogeny in Young & Andrade (2009) has demonstrated, the contemporaneous species D. maximus and D. manselii have distinct cranial apomorphies. As such, only teeth from the Swabian Alb of the uppermost Kimmeridgian and lowermost Tithonian are here considered to belong to D. maximus . All other isolated teeth are hereby referred to Dakosaurus sp. until further studies can determine if the tooth-crowns possess species-level apomorphies.

Invalid species: Dakosaurus amazonicus was erected by Giebel (1870) for vertebrae and teeth found in the Amazon. However, Gervais (1876) erected the name Dinosuchus terror (currently considered to be an alligatorid closely related to Purussaurus ) for the material. Giebel (1876) considered Dinosuchus terror to be a junior synonym of Dakosaurus amazonicus .

Etymology: ‘Tearing lizard’. Dakos - is Ancient Greek for ‘to tear’, referring to the large, lateromedially compressed, and serrated teeth.

Geological range: Lower Oxfordian (mariae ammonite zone; NHM 47989)–lower Berriasian (Gasparini et al., 2006).

Geographical range: Cosmopolitan ( Argentina, England, France, Germany, Mexico, Poland, and Switzerland; and possibly Russia).

Diagnosis: Metriorhynchid thalattosuchian with large robust teeth, with little lateromedial compression, and with the carinae formed by denticles that are wider transversely than in the root–apex direction; cranial bones smooth, lacking conspicuous ornamentation; acute angle formed by the lateral and medial processes of the frontal; the supratemporal fenestrae reach the minimum intraorbital distance; the lateral mandibular groove possesses a well-developed foramen at either end; surangular poorly developed, terminating caudal to the anterior margin of the orbit; the distance between the ventral margin of the antorbital fenestra and the ventral margin of the tooth row is greater than the diameter of the antorbital fenestra; the cross-sectional thickness of the cranial bone is generally> 1.5 mm.

DAKOSAURUS ANDINIENSIS VIGNAUD & GASPARINI, 1996

1985 Metriorhynchus aff. durobrivensis ; Gasparini

1995 Dakosaurus sp. ; Vignaud

1996 Dakosaurus andiniensis sp. nov.; Vignaud & Gasparini

Holotype: MHNSR PV344 , poorly preserved snout lacking teeth.

Type locality: Catan Lil, Province of Mendoza, Argentina (Vaca Muerta Formation).

Etymology: ‘Tearing lizard from the Andes’.

Geological range: Upper Tithonian–lower Berriasian.

Geographical range: Provinces of Mendoza and Neuquén, Argentina .

Referred specimens: MOZ 6146P, skull with articulated mandible and fragmentary postcrania (upper Tithonian of Pampa Tril, Neuquén Province); MOZ 6140P, anterior mandibular fragment (lower Berriasian of Pampa Tril, Neuquén Province).