Leitoscoloplos latibranchus Day, 1977

Zhadan, Anna, 2020, Review of Orbiniidae (Annelida, Sedentaria) from Australia, Zootaxa 4860 (4), pp. 451-502 : 469

Leitoscoloplos latibranchus Day, 1977

Figure 10

Leitoscoloplos latibranchus Day, 1977:225–226 , fig. 1e–g; Mackie 1987: 12–13, fig. 12a–e.

Material examined. Queensland: Calliope River, Gladstone, 23°51’S, 151°10’E, coll. P. Saenger, AM W.199322, many specimens. South Australia: mouth of the Murray River , 35°32’S, 138°50’ E, 31.12.1971, coll. P.A. Hutchings, under boulders in mud, AM W.7347, Holotype and paratyes AM W.7356, 8 specimens, all from same locality.

Type locality. Murray River Heads, South Australia .

Description. Small worms, thoracic width 0.8 mm, body length about 20 mm in holotype ( Fig. 10A, B ). Body cylindrical, thorax only slightly flattened; 16–17 thoracic chaetigers ( Fig. 10 A–D). Branchiae from chaetiger 19–21 as small, triangular lamellae, then increasing in size and becoming broad and low triangular, often with tips drawn towards medial line of body, branchiae becoming narrower near pygidium ( Fig. 10D, F, G, I ). Thoracic postchaetal lobes absent on most thoracic segments, becoming noticeable only in posterior thorax as small papillae ( Fig. 10E, H ). No subpodal or stomach papillae. Abdominal notopodial lobes short, thin, foliaceous, shorter than branchiae ( Fig. 10E, F, I ). Neuropodial lobes weakly bilobed in anterior segments, then outer lobes reduced and lobes becoming uniramous ( Fig. 10E, F, I ). Subpodal notch and narrow flange present. Pygidium with two dorso-lateral anal cirri ( Fig. 10G ). Chaetae crenulate capillaries in all parapodia, no uncini or forked chaetae present ( Fig. 10H, I ).

Distribution. Australia, Queensland, South Australia.

Habitat. Mud.

Remarks. Leitoscoloplos latibranchus differs from the other species of the genus by the presence of short and broad branchiae. The studied specimens are in agreement with the descriptions by Day (1977) and Mackie (1987). The present study expands the distribution of L. latibranchus to Queensland.

Figures

FIGURE 10. Leitoscoloplos latibranchus. A, C:AM W.7347 (holotype), B, D–I:AM W.199322.A–G: stereomicroscope, methylene blue staining; H, I: compound microscope. A. General view; B. General view; C. Anterior part of the body, dorsal view; D. Anterior part of the body, dorso-lateral view; E. Thorax-abdomen transition, lateral view; F. Abdomen, dorsal view; G. Posterior end of the body, latero-posterior view; H. Parapodium of chaetiger 2; I. Parapodia of abdominal chaetiger. a, acicula; br, branchia; cc, crenulated capillaries; ne, neuropodium; no, notopodium.