Undichna cf. britannica Higgs, 1988

Moreau, Jean-David & Gand, Georges, 2022, New data on the Permian ecosystem of the Rodez Basin: ichnofauna (traces of protostomians, tetrapods and fishes), jellyfishes and plants from Banassac-Canilhac (Lozère, southern France), Geodiversitas 44 (31), pp. 975-987 : 982

Undichna cf. britannica Higgs, 1988

( Fig. 7 A-G)

MATERIAL EXAMINED. — M486_ 2022.1.8, slab bearing numerous trails preserved as convex hyporeliefs.

DESCRIPTION

The slab bears many wavy, horizontal, intermittent, sharp and up to 1.0 mm wide ridges ( Fig. 7A, B, D ). Some of these ridges form trails consisting of two intertwined and out-of-phase waves ( Fig. 7 E-G). The longest trail is 145 mm long. Waves show a wavelength of up to 40 mm and an amplitude of up to 5 mm. In some trails, one of the waves shows a low amplitude, whereas the other shows a greatest amplitude ( Fig.7F ). Some trails show outer marks that are parallel to central waves ( Fig. 7E, G ).

REMARKS

The presence of wavy, intertwined, horizontal, and intermittent, grooves/ridges is characteristic of several Undichna Anderson,1976 ichnospecies (e.g. Undichna quina from the Permian deposits of the Falkland Island, Trewin2000; Undichna britannica from the Carboniferous deposits of England, Higgs 1988). Since ridges are out-of-phase in specimens from Le Bousquet it should be tempting to see similarities with U. britannica (see Higgs 1988 and Minter & Braddy 2006). In contrast, amongst U. quina ridges are in phase (see Trewin 2000). On trails showing strong variation of amplitude between the two waves ( Fig.7F ), the wave with the lowest amplitude was probably made by the anal fin whereas the wave with a greatest amplitude was probably made by the caudal fin.Outer marks were probably made by pelvic fins.

Figures

FIG. 7. — Slab showing the co-occurrence of tetrapod swimming tracks (Characichnos isp.) and fish trails (Undichna cf. britannica Higgs, 1988): A, photograph; B, interpretative sketch showing tetrapod swimming tracks (in red) and fish trails (in black); C, interpretative sketch showing only tetrapod swimming tracks; D, interpretative sketch showing only fish trails; E-G, details of fish trails. M486_2022.1.8. Scale bars: 2 cm.