Scoloplos dayi Hartmann-Schröder & Hartmann, 1980

Zhadan, Anna, 2020, Review of Orbiniidae (Annelida, Sedentaria) from Australia, Zootaxa 4860 (4), pp. 451-502 : 457

Scoloplos dayi Hartmann-Schröder & Hartmann, 1980

Scoloplos dayi Hartmann-Schröder & Hartmann, 1980:67–68 , figs 74–78.

Scoloplos dayi: Zhadan et al., 2015:781–785 , figs 2, 3, 12B.

Material examined. Western Australia: Exmouth, Town Beach , sand: Holotype, HZM P–16373 ; Exmouth-Gulf , fine sand: Paratype, HZM P–16374 . Queensland: Lizard Island, August 2013: Off Casuarina Beach , 14°40’46”S, 145°26’49”E, snorkeling, depth 0.5 m, sand, seagrass, coll. K. Meissner, N. Budaeva, A. Murray, AM W.44249, 2 specimens ; same station, AM W.45477, 1 specimen ; off Watson’s Bay , 14°39’41”S, 145°26’27”E, SCUBA diving, depth 14 m, sandy mud, AM W.45476, 1 specimen ; off Casuarina Beach, in front of Lizard Island Research Station , 14°40’46”S, 145°26’49”E, intertidal, sand, coll. J. Parapar, Q. Parapar, P.A. Hutchings, P. Rodgers, AM W.46093, 3 specimens ; Casuarina Beach , 14°40’46”S, 145°26’49”E, intertidal, sand, coll. P.A. Hutchings, P. Rodgers, J. Zanol Silva, N. Budaeva, AM W.46095, 9 specimens ; same station, AM W.44764, 1 specimen .

Type locality. Exmouth: Town Beach , Western Australia .

Description (after Zhadan et al., 2015). Body cylindrical; anterior thorax often swollen; posterior thorax slightly wider than abdomen. Colour in life orange-brown with red blood vessels, ventral part of abdomen grey. Thoracic width up to 2.2 mm. Prostomium sharply conical. Peristomium with a pair of dorso-lateral nuchal organs. Thoracic chaetigers numbering 21–26 (usually 24–25). Branchiae from chaetiger 8 (rarely 9–11) as minute papillae, gradually increasing in size; in chaetiger 17–20 becoming large, triangular with tapering tips; in abdomen long narrow triangular, as long as notopodia or slightly longer. Thoracic post-chaetal lobes present from chaetiger 1, first neuropodial lobe very small; both notopodial and neuropodial lobes gradually increasing in size, becoming digitiform; in anterior thorax similar in size, in posterior thorax notopodial lobes longer. Lateral organs developed at base of notopodia. Neuropodial lobes becoming bilobed from chaetiger 10–12, in some specimens 13–14. No subpodal or stomach papillae. Abdominal notopodial lobes narrowly foliaceous, with slightly swollen basal part. Abdominal neuropodial lobes supported by two thin aciculae and bilobed; with elongate triangular lobes, inner lobe 2–3 times longer than outer. Subpodal flange well developed, upper edge forming flange papilla (ventral cirrus) in all abdominal segments. Low interramal papilla present between rami in some specimens. Ciliated dorsal organs with two curved ciliated strips present mid-dorsally in each segment. Thoracic notopodia bearing only crenulated capillary chaetae; all thoracic neuropodia with an anterior J-shaped row of slightly curved hooded uncini and 3–4 rows of crenulated capillary chaetae; uncini smooth or slightly serrated. Crenulated capillary chaetae accompanied by forked chaetae in abdominal notopodia and flail chaetae in abdominal neuropodia. Pygidium with two anal cirri.

Distribution. Australia, Western Australia, Queensland.

Habitat. Intertidal and upper subtidal, sand, sandy mud.

Remarks. Scoloplos dayi was described from the Northwest coast of Australia, and then redescribed and illustrated based on type material and specimens from Lizard Island, Queensland ( Zhadan et al. 2015). Scoloplos dayi is similar to Leitoscoloplos bifurcatus (Hartman 1957) , and these two species inhabited the same environments on Lizard Island ( Zhadan et al. 2015). The only differences between these two species are the presence of thoracic uncini (sometimes very short and inconspicuous) and flange papillae in S. dayi . In general, this species also has more thoracic chaetigers (21–26, usually 24–25), but this character overlaps with L. bifurcatus .