Parmaichnus, Pervesler & Uchman, 2009

Pervesler, Peter & Uchman, Alfred, 2009, A new Y-shaped trace fossil attributed to upogebiid crustaceans from Early Pleistocene of Italy, Acta Palaeontologica Polonica 54 (1), pp. 135-142 : 136

Ichnogenus Parmaichnus nov.

Type ichnospecies: Parmaichnus stironensis isp. nov.

Etymology: After the Parma region, in which the trace fossil occurs.

Diagnosis.—Vertical to oblique, tubular burrows, circular in cross section, and composed of the U−shaped upper part and a basal shaft. Sub−spherical swellings are present in the upper part of the burrow.

Remarks.—To date, only three Y−shaped ichnogenera (U−shaped upper part with a basal shaft) are distinguished. They can be compared to Parmaichnus . Psilonichnus Frey, Curran, and Pemberton, 1984 , typified by Psilonichnus tubiformis ( Fürsich, 1981) , has no turning chambers and is much larger ( Fig. 5U ). Solemyatuba Seilacher, 1990 , with two ichnospecies S. subcompressa (Eichwald, 1855) and S. ypsilon Seilacher, 1990 , and Recent burrows of the bivalve Solemya velum Say, 1822 are of comparable size but they do not display turning chambers and their tubes are elliptical in cross section ( Fig. 5F, G ). Polykladichnus Fürsich, 1981 , typified by P. irregularis Fürsich, 1981 ( Fig. 5D ), displays multiple Y− or U−shaped bifurcation and slight enlargement at junctions (see Schlirf and Uchman 2005).

Figures

Fig. 5. Different Y−shaped trace fossils (B, D, G, U) and Recent burrows compared to Parmaichnus stironensis (P–S). Redrawn from photographs. A. After Seike and Nara (2007: fig. 3c). B. Holotype of Psilonichnus upsilon, Hanna Bay, San Salvador, Bahamas, from AU photograph. C. After Bruce (1987: fig. 6). D. After Fürsich (1981: pl. 3: 2). E. After Curran and Frey (1977: pl. 1e). F. After Frey (1968: text−fig. 1). G. After Seilacher (1990: fig. 5D). H. After Dworschak (2004: fig. 2B); arrows point the turning chambers. I. After Swinbanks and Luternauer (1987: fig. 2.1). J. After Ott et al. (1976: pl. 1: 2). K. After Ott et al. (1976: pl. 1: 3). L. After Dworschak et al. (2006: fig. 1A). M. After Nash et al. (1984: pl. 2a); see also Bromley (1996: fig. 4.32). N. After Curran and Martin (2003: fig. 6). O. After Asgaard et al. (1997: fig. 6). P–S. Parmaichnus stironensis igen. nov. et isp. nov. P. Holotype, ING UJ 200P11, see also Fig. 3. Q. P1070193, see also Fig. 4B. R. P1070182, see also Fig. 4A. S. P1070196, see also Fig. 4D. T. After Atkinson and Taylor (1991: fig. 1f). U. Psilonichnus tubiformis, after Fürsich (1981: pl. 1: 1).