Callograptus ulahensis, Rickards, R. B., Chapman, A. J., Wright, A. J. & Packham, G. H, 2003

Rickards, R. B., Chapman, A. J., Wright, A. J. & Packham, G. H, 2003, Dendroid and Tuboid Graptolites from the Llandovery (Silurian) of the Four Mile Creek Area, New South Wales, Records of the Australian Museum 55 (3), pp. 305-330 : 319-320

Callograptus ulahensis n.sp.

Figs. 16A , 17A

Material. HOLOTYPE AM F114760 and PARATYPE AM F114780 , both from BF15, S of junction of Four Mile Creek and Bridge Creek .

Derivation of name. After Ulah property.

Diagnosis. Callograptus with fan-like stipe clusters, connected by uncommon, hair-like dissepiments; branching in rough zones resulting in slender parallel stipes; and very simple autothecae spaced at 20 in 10 mm.

Description. Both specimens exhibit rather slender stipes 0.20–0.30 mm in lateral width and 0.40–0.50 mm in dorsoventral width. The autothecal apertures are simple, non-denticulate, spaced at 20 in 10 mm and the apertures themselves occupy almost half of the dorsoventral width. The larger specimen ( Fig. 16A ) suggests broad branching zones. The stipes are connected by irregular and uncommon hair-like dissepiments which may be more common in the regions of the branching zones. No bithecae have been detected.

Remarks. This very simple and slender-stiped Callograptus bears no resemblance to any of the Silurian callograptids reviewed under the Remarks section above of the description of C. bridgecreekensis . Callograptus ulahensis has a different branching pattern to C. bridgecreekensis and a much wider thecal spacing (20 in 10 mm compared with 30–35 in 10 mm).

Figures

Fig. 16. A, Callograptus ulahensis n.sp., AM F114760, holotype, BF15; B, Callograptus niagarensis, AM F114739, W885; C–E, Pseudodictyonema graptolithorum, respectivelyAM F114755,AM F114753 and AM F114645, all from F14. Scale bars 1 mm.

Fig. 17. A, Callograptus ulahensis n.sp., AM F114760, holotype, BF15; B, Stelechocladia praeattenuata n.sp.,AM F114743, holotype, BF28; C,D, Acanthograptus praedeckeri praedeckeri n.sp., respectivelyAM F114792, holotype, BF28 and AM F114568a, F14. Scale bars 1 mm.