Caulostrepsis taeniola Clarke, 1908

Gaaloul, Nadia, Uchman, Alfred, Ali, Syrine Ben, Janiszewska, Katarzyna, Stolarski, Jarosław, Kołodziej, Bogusław & Riahi, Sami, 2023, In vivo and post-mortem bioerosion traces in solitary corals from the upper Pliocene deposits of Tunisia, Acta Palaeontologica Polonica 68 (4), pp. 659-681 : 667

Caulostrepsis taeniola Clarke, 1908

Figs. 8B, D , 9A 4 , SOM 1.

Diagnosis.—Gallery cylindrical, bent in a narrow U-form which is sometimes enlarged in the shape of a tongue. The inward facing margins of the limbs are always interconnected by a distinct vane. Limbs closer or partially fused towards the apertural extremity. Transverse section dumbbell-shaped, aperture 8-shaped (cited from Bromley and D’Alessandro 1983).

Material.—INGUJ265P153, 154, 161, 162, 180; U-shaped, tongue depressions on the surface of coralla; El Melah stream section, the upper part of the Argiles de Sidi Barka Formation (upper Pliocene) of Tunisia.

Description.—A narrow, straight, curved, or slightly winding tongue depression running along the surface of coralla within the corallum wall, usually along their axis. The depression widens slightly distally. It is bordered by semi-circular cylindrical marginal gutter (limbs). The distal part of some depressions has a thin roof built of the corallum wall. The vane (the area between the limbs) is equal to or wider than the limbs. The boring is up to 21 mm long and up to 1–1.5 mm wide. It is concentrated in the corallum wall (SOM 1 available at http://app.pan.pl/SOM/app68-Gaaloul_ etal_SOM.pdf).

Remarks.—The presence of the roof at the end of some depressions suggests that the roof was more extensive but was broken or collapsed. Caulostrepsis taeniola is the most common ichnospecies of Caulostrepsis . It is produced mainly by the spionid polychaete Polydora ciliata ( Johnston, 1838) , which is common on mid-latitude Atlantic coasts ( Radwański 1969, and references therein), mostly up to a depth of 25 m ( Boekschoten 1966). Polydora lives in different substrates and conditions; it can also live in polar regions ( Hanken et al. 2012) and in brackish waters ( D’Andrea et al. 1996; Murina 1997).

Stratigraphic and geographic range.—Lower Devonian– Recent, worldwide, Cenzoic occurrences mostly in the Atlantic and the Mediterranean regions.

Figures

Fig. 8. Caulostrepsis, a domichnion produced by polychates, in the skeleton of caryophylliid coral Ceratotrochus (Edwardsotrochus) duodecimcostatus Goldfuss, 1826), from the El Melah stream section, the upper part of the Argiles de Sidi Barka Formation (upper Pliocene) of Tunisia. A. Caulostrepsis cretacea (Voigt, 1971), INGUJ265P156. B. Caulostrepsis taeniola Clarke, 1908 and Pinaceocladichnus onubensis Mayoral, 1988 (Pn), INGUJ265P154. C.Caulostrepsis avipesBromleyand D’Alessandro,1983,INGUJ265P176.D.A clusterofCaulostrepsis taeniolaClarke,1908,INGUJ265P162.E–G.Caulostrepsis penicillus isp. nov. E. INGUJ265P158 holotype (a), and paratype (b). F. INGUJ265P174 paratype. G. INGUJ265P172, partial views (G1, G2).

Fig. 9. Snapshots from micro-CT images of Caulostrepsis in the skeleton of caryophylliid coral Ceratotrochus (Edwardsotrochus) duodecimcostatus Goldfuss, 1826) (INGUJ265P153), from the El Melah stream section, the upper part of theArgiles de Sidi Barka Formation (upper Pliocene) of Tunisia. A. The surface with indications of bioerosion traces, with partial transparency, and without corallum, A1–A4, respectively; Ct, Caulostrepsis taeniola Clarke, 1908; Me, Maeandropolydora elegans Bromley and D’Alessandro, 1983. B. View from the other side, B1–B4, respectively; Ca, Caulostrepsis avipes Bromley and D’Alessandro, 1983.

Fig.4. Exposures of the El Melah stream the section, upper part of theArgiles de Sidi Barka Formation (upper Pliocene) of Tunisia.A. Coral level III.General view (A1), close view of the sampling area (A2). B. The coral level II/coral level III boundary.C. Coral level II. General view (C1), close view of the sampling area (C2). D. General view of coral level I. Quadrangles indicate sampling areas.