Rhynchosauroidae Haubold, 1966

Ptaszyński, Tadeusz & Niedźwiedzki, Grzegorz, 2004, Late Permian vertebrate tracks from the Tumlin Sandstone, Holy Cross Mountains, Poland, Acta Palaeontologica Polonica 49 (2), pp. 289-320 : 295-297

Ichnofamily Rhynchosauroidae Haubold, 1966

Small and middle sized tracks of lacertoid animals. Pedal pace width is usually larger than manual one. Pedal pace angulation ranges from about 70° up to 135°. Manual imprints are situated variously in relation to pedal ones: in front, at the same line, or may be overstepped by them, depending on the speed of movement. Both pes and manus have five, clawed digits. Digits V are situated laterally and somewhat posteriorly to the group I–IV. The size and shape of pedal and manual imprints are differentiated. Pedal imprints are narrow, digitigrade. Digits I–IV increase in length from I to IV; III and IV may be equal in length. The digit V may be as long as digit III ( Rhynchosauroides , Paradoxichnium ) or much shorter ( Phalangichnus ). Manual imprints are more plantigrade, with digit I–IV length ratios similar to pedal ones. Digits I and V may be absent from shallow tracks.

The ichnofamily Rhynchosauroidae includes ichnogenera: Rhynchosauroides Maidwell, 1911 ; Paradoxichnium Müller, 1959 ; Palmichnus Schmidt, 1959 ; Phalangichnus Schmidt, 1959 ; Dromopus Marsh, 1894 .

Remarks.—Ichnofamily Rhynchosauroidae was described as monogeneric, comprising lacertoid footprints derived at first from Triassic sediments. Later, representatives of the ichnogenus Rhynchosauroides were found in the Upper Permian Val Gardena Sandstone ( Conti et al. 1977; Ceoloni et al. 1988). The ichnogenera: Paradoxichnium Müller, 1959 ; Palmichnus Schmidt, 1959 and Phalangichnus Schmidt, 1959 have been documented from the latter, Cornberg Sandstone and ”Terrestrischer Zechstein” ( Müller 1959). These ichnogenera resemble Rhynchosauroides , showing varied situation of manual and pedal imprints in trackways and differentiated pedal and manual pace width. This ichnofamily may also include the questionable and poorly documented (see Haubold et al. 1995; Haubold 1996; Haubold and Stapf 1998) and therefore problematic ichnogenus Anhomoiichnium Dozy, 1935 .

We regard the trackmakers of those ichnogenera as taxonomically close animals and agree with suggestion of Haubold (1971b), that they all represent lacertoid type of imprints.

The problem of formal presence of lacertoid vertebrate ichnogenera Palmichnus and Phalangichnus (compare: Haubold et al. 1995; Haubold 1996; McKeever and Haubold 1996; Haubold and Stapf 1998) in the ichnological nomenclature should be once again revised with support of existing materials and new finds from the Holy Cross Mountains. Unsatisfactory preservation (lack of details) in many cases makes their precise recognition impossible. Possibly many of specimens assigned to the ichnogenus Chelichnus (in the sense of Haubold et al. 1995; Haubold 1996; McKeever and Haubold 1996; Haubold and Stapf 1998) have been made by Rhynchosauroidae trackmakers.

We suggest also a reinterpretation of Phalangichnus simulans Schmidt, 1959 and P. perwangeri Conti et al., 1977 . Both trackway descriptions are based on poorly preserved material made, possibly, by more than one trackmaker, and therefore trackway features of these ichnospecies have been erroneously interpreted.

Here we accept the existing formal nomenclature of ichnogenera Paradoxichnium Müller, 1959 ; Palmichnus Schmidt, 1959 and Phalangichnus Schmidt, 1959 .