Cretodytes Ponomarenko, 1977

Prokin, Alexander A., Petrov, Pyotr N., Wang, Bo & Ponomarenko, Alexander G., 2013, New fossil taxa and notes on the Mesozoic evolution of Liadytidae and Dytiscidae (Coleoptera), Zootaxa 3666 (2), pp. 137-159 : 152

Cretodytes Ponomarenko, 1977

Type species: Cretodytes latipes Ponomarenko, 1977 .

Notes: The genus is characterized by the short lateral lobe of the metaventrite, deep and rather wide cavity at the apex of the anterior metaventral process, and elevated median platforms of metacoxae, which are weakly diverging, but dilated and rounded apically. It differs from Palaeodytes in the longest point of the metacoxal plate situated at the level of the external margin of mesocoxae, and in the shorter lateral lobe of the metaventrite (which also distinguishes it from Liadytiscinae); from " Palaeodytes " incompletus it differs in the shape of the lateral lobe of the metaventrite and shape of the metacoxal processes; and from Sinoporus, in the concave posterior margins of the lateral lobes of the metaventrite (cf. Figs 20 and 23 ).

The new species belongs to this genus according to the combination of two characters: metacoxal plate three times as long as the lateral lobe of the metaventrite and absence of a laterally limited elevated median area of the metaventrite.

Figures

FIGURES 19 – 21. Cretodytes incertus sp. n.: (19) photo of holotype, (20) line drawing of holotype; (21) Angaragabus jurassicus Ponomarenko, 1963: photo of holotype, PIN 1670 / 390.

FIGURES 22 – 24. (22) Ilybius adygheanus Petrov, Shapovalov & Fery, 2010: metaventrite and metacoxa, with measurements WC, WS, LC and LV shown; modified from Petrov et al. (2010); (23) Sinoporus lineatus Prokin & Ren, 2010: holotype in ventral view, redrawn and modified from original description with LC and LV shown (in this case the longest point of the lateral lobe of the metaventrite is at the very base of the lobe; it has been measured immediately lateral of the posterior margins of the mesocoxa, i. e., at the very base of the lobe, if we define the lobe as the part of the metaventrite lateral of the mesocoxa); (24) Lancetes lanceolatus (Clark, 1863): metaventrite of recent specimen from Lake Cronin (Western Australia); arrow indicates impression at lateral margin of median elevated area of metaventrite.