Helicerina Brönnimann and Masse, 1968

Kietzmann, Diego A., Blau, Joachim, Fernández, Diana E. & Palma, Ricardo M., 2010, Crustacean microcoprolites from the Upper Jurassic- Lower Cretaceous of the Neuquén Basin, Argentina: Systematics and biostratigraphic implications, Acta Palaeontologica Polonica 55 (2), pp. 277-284 : 281

Ichnogenus Helicerina Brönnimann and Masse, 1968

Type ichnospecies: Helicerina spinosa Brönnimann and Masse, 1968 , southern France, late Barremian lower Aptian .

Diagnosis.—The ichnogenus Helicerina is characterised by triangular or diamond−shaped canals within the symmetry plane of cross sections. Laterally, rounded shaped canals can develop from spine−like extensions of the central canals ( Brönnimann and Masse 1968 emended by Schweigert et al. 1997).

Remarks.—This ichnogenus contains 7 ichnospecies ( Fig. 3 ) known from the Middle Triassic to the Miocene ( Schweigert et al. 1997; Blau and Grün 2000), but only H. siciliana Senowari−Daryan, Schäfer, and Catalano 1979 is know from the Jurassic (Upper Triassic and Middle Jurassic; see Schweigert et al. 1997). Two possibly new ichnospecies are described herein.

Figures

Fig. 3. Schematic diagrams of the different ichnospecies of Palaxius and Helicerina mentioned in this work (Modified from Blau and Grün (2000), not to scale). A. Palaxius ichnospecies with 4 canals: Palaxius caucaensis (A1), P. kumaensis (A2), P. salataensis (A3), P. tetraochetarius (A4), P. osaensis (A5), and P. azulensis Kietzmann isp. nov (A6). B. Palaxius ichnospecies with 10 canals: Palaxius colombiensis (B1), P. decaochetarius (B2), P. habanensis (B3), P. decemlunulatus (B4), P. decemporatus (B5), and P. caracuraensis Kietzmann isp. nov. (B6). C. Helicerina ichnospecies with simple canals: Helicerina siciliana (C1), H. alata (C2), H. spinosa (C3), H. keuperiana (C4), and Helicerina isp. A aff. H. siciliana (C5). D. Helicerina isp. with multiple canals: Helicerina ruttei (D1), H. kainachensis (D2), H. kalakyra (D3), and Helicerina isp. B (D4).