Asaphellus sp. 1

Arcerito, Facundo René Meroi, Waisfeld, Beatriz & Balseiro, Diego, 2015, Diversification of Asaphellus Callaway, 1877 (Asaphidae: Trilobita) during the Tremadocian in South West Gondwana (Cordillera Oriental, Argentina), Geodiversitas 37 (2), pp. 131-150 : 145-146

Asaphellus sp. 1

( Fig. 7 C-F)

Asaphellus catamarcensis – Harrington 1938: 246, pl. 13, fig. 10. non pl. 13, figs 3-6, 8, 9. — Harrington & Leanza 1957: 147-151, figs 65.7, 65.8; non figs 65.1-6; 64.1-6. — Tortello & Rao 2000: 72, 73, figs 3T-V. — Tortello, Esteban & Aceñolaza 2002: 137, figs 5C, D. — Aceñolaza, Aráoz, Vergel, Tortello & Nieva 2003: 23-28, pl. 1A; non pl. 1B. — Tortello & Aceñolaza 2010: 162, figs 4 D-H; non figs 4 A-C, I.

MATERIAL. — 4 pygidia; 1 fragmentary pygidium with attached thorax and free cheek. CEGH-UNC 25765-25767.

OCCURRENCE AND AGE. — Horizon DLA 20, DLA 25. Upper Alfarcito Member and lower Rupasca Member of the Santa Rosita Formation, Santa Victoria Group. Late Tr1 and early Tr2.

REMARKS

This species is scanty in our samples; it differs from all others described herein in a semicircular outline, a well-defined wide axis, with up to five rings visible on some specimens, a well-defined border, and a wide subparallel doublure (on average about twice wider than the border). Specimens of this morphotype have been referred to A. catamarcensis by different authors, among them, one pygidium illustrated by Harrington (1938: pl. 13, fig. 10) from Angosto de Parcha (Pascha-Incamayo area, Salta), and two pygidia figured by Harrington & Leanza (1957: fig. 65.7, 8) from Sierra de Mojotoro (Quebrada de los Canchos, Caldera Department, Salta). Later, Tortello & Rao (2000), Tortello et al. (2002), Aceñolaza et al. (2003), and Tortello & Aceñolaza (2010) accommodated the material from Angosto de Lampazar(Pascha- Incamayo area) and Abra de Zenta in A. catamarcensis , based on the resemblance with the pygidia from Sierra de Mojotoro that Harrington & Leanza (1957: pl. 65, figs 7, 8) referred to that species. However, the type pygidium of A. catamarcensis reillustrated herein differs from these previous assignments (see A. catamarcensis remarks). In addition, the cranidium refer in Tortello & Aceñolaza (2010: figs 4a, b) doubtfully could be assigned to Asaphellus (see A. catamarcensis remarks). Thus, we refer the material mentioned above tentatively to Asaphellus sp. 1 . Nonetheless, additional material would be required in order to be certain about the generic assignment of this material.

Asaphellus sp. 1 resembles A. verus Zhou in Chen, Zhou, Zou, Lin, Yang, Wang, Qi, Wang & Lu, 1980, from the Hebei Province, China ( Zhou & Fortey 1986: pl. 8, figs 9-24, pls 9, 1-3, 6) mainly in the pygidial outline and proportions, and the shape of the axis, however, in the Chinese species the axis is better segmented along its length and the pleural fields are wider (tr.).

Figures

FIG. 7. — A, B, Asaphellus sp. 2, pygidia in dorsal view: A, CEGH-UNC 25763; B, CEGH-UNC 25764; C-F, Asaphellus sp. 1, CEGH-UNC 25765-25768; C, pygidium, latex cast, dorsal view, CEGH-UNC 25765; D, pygidium, dorsal view, CEGH-UNC 25766; E, pygidium, dorsal view, CEGH-UNC 25765; F, pygidium and thorax, dorsal view,CEGH-UNC 25767;G, A. isabelae n. sp., articulated juvenile, latex cast, dorsal view,CEGH-UNC 25762. Scale bars: A-F, 0.5 cm; G, 0.25 cm. All specimens come from the Quebrada del Arenal, Santa Rosita Formation, Santa Victoria Group: A, B, G, from DLA 28; C, E, from DLA 25; D, F, from DLA 20.