Spinograptus clathrospinosus ( Eisenack, 1951 )

Kozłowska-Dawidziuk, Anna, 2002, Agastograptus, a synonym of Plectograptus (Retiolitidae, Graptolithina), Acta Palaeontologica Polonica 47 (3), pp. 459-467 : 464

Spinograptus clathrospinosus ( Eisenack, 1951)

Fig. 3C, G .

Retiolites clathrospinosus n. sp.; Eisenack 1951: 139, pl. 23: 1, 2.

Spinograptus cf. spinosus (Wood) ; Lenz 1978: 636, pl. 7: 3, 4.

Agastograptus clathrospinosus (Eisenack) ; Lenz 1993: 15–16, pl. 3:1, 2, 4, 7, pl. 4: 6, 8.

Spinograptus clathrospinosus (Eisenack) ; Kozłowska−Dawidziuk 1995: 314, pl. 31B, pl. 32C.

Agastograptus clathrospinosus (Eisenack) ; Richards, Packham, Wright and Williamson 1995: 34: fig. 18D.

Spinograptus clathrospinosus (Eisenack) ; Kozłowska−Dawidziuk 1997: 405, fig. 13A, B.

Agastograptus clathrospinosus (Eisenack) ; Zhang and Lenz 1997: 1225, fig. 3G–J.

non Agastograptus clathrospinosus (Eisenack) ; Lenz 1993: 15–16, pl. 3: 3, 5, 6, pl. 4: 1–5, 7.

Diagnosis.—See Kozłowska−Dawidziuk 1997.

Description.—The new material displays similar preservation and features as those described before ( Eisenack 1951; Lenz 1993; Kozłowska−Dawidziuk 1995).

Discussion.— S. clathrospinosus displays a well developed reticulum of the ancora sleeve with a marked zigzag in its dorsal part, and poorly developed mid−ventral lists, as well as long, thin apertural processes with reticulofusellar structure clearly visible throughout their length ( Fig. 3C, G ). S. clathrospinosus is similar to S. spinosus in size of rhabdosome, weak mid−ventral lists and ancora sleeve reticulum, but differs in apertural processes, which are thinner in S. spinosus , with reticulofusellar structure marked only at their distal ends.

Material.—Seven fragments from depth 1631.2 m, Bartoszyce borehole, Poland, EEP.

Occurrence.— Neodiversograptus nilssoni Biozone of erratic boulders from an undescribed location ( Eisenack 1951), in Kaliningrad area, Russia ( Obut and Zaslavskaya 1983), and Poland ( Kozłowska−Dawidziuk 1995), Colonograptus predeubeli – C. debeli and C. ludensis biozones of Arctic Canada ( Lenz 1993), C. ludensis and L. progenitor biozones in South China ( Zhang and Lenz 1997), and the upper part of the Pristiograptus parvus – Gothograptus nassa Biozone at Všeradice, Barrandian, Czech Republic ( Kozłowska−Dawidziuk et al. 2001).

Figures

Fig. 3. A, H. Spinograptus munchi (Eisenack, 1951), A. ZPAL G. 27/3, EEP, Bartoszyce borehole, depth 1626.6 m, reverse view of mature rhabdosome. H. ZPAL G. 27/7, EEP Mielnik borehole, depth 1044.0 m, enlargement of paired apertural processes of distal theca. B, E, F. Neogothograptus balticus (Eisenack, 1951), Baltic erratic boulder 46 from Jarosławiec. B, E. ZPAL G. 27/4 mature rhabdosome with appendix (photo D. Bates). B. Reverse view. E. Ventral view of thecae 12 side. F. ZPAL G. 27/5 enlargement of single reticular apertural process. C, G. Spinograptus clathrospinosus (Eisenack, 1951), C. GSC120736, Arctic Canada, Cornwallis Island, AB−97 25 m, stereopair of immature rhabdosome, reverse view (modified after Lenz and Kozłowska− Dawidziuk 2002: fig. 13: 6). G. ZPAL G. 27/6, EEP, Bartoszyce borehole, depth 1631.2 m, paired apertural processes of medial theca. D. Cometograptus nevadensis (Berry and Murphy, 1975), GSC 99161, Arctic Canada, Cornwallis Island, SBC10E (modified after Lenz 1993: pl. 19: 1), ventro−latral view of rhabdosome. Scale bars 1 mm except for D, F–H which is 0.5 mm. Abbreviations as Fig. 2.