Daylithos cinctus ( Haswell, 1892 ) Salazar-Vallejo, 2012

Salazar-Vallejo, Sergio I., 2012, 3562, Zootaxa 3562, pp. 1-62 : 50-52

Daylithos cinctus ( Haswell, 1892) n. comb.

Figure 20

Stylarioides cinctus Haswell 1892:333–334 , Pl. 26, Figs 4–5, Pl. 27, Figs 10, 15, 16, 21, Pl. 28, Fig. 24; Fauvel 1917:255, Fig. 25.

Type material. Australia. Neotype ( AM W5370 ), collected in River Heads, Hervey Bay (25°00'00" S, 153°00'00" E), Queensland, low tide level, in mud between oyster covered boulders. 4 Jan. 1971, P. Hutchings, coll.

Description. Neotype (AM W5370), cylindrical, anteriorly swollen, posteriorly tapered; 27 mm long, 4 mm wide, cephalic cage 8 mm long, 77 chaetigers. Body surface mostly detached (probably because its tunic is delicate or because of an extended preservation in formalin), dark, almost black, without tunic or sediment cover ( Fig. 20A); body papillae digitate, in two irregular rows per segment.

Cephalic hood not exposed. Not dissected to avoid further damage. Cephalic cage chaetae about 1/3 as long as body length, or twice as long as body width. Cephalic cage made by chaetigers 1–2, chaetal bundles with chaetae arranged in dorso- and ventrolateral rows. First chaetiger with 10 noto- and 14 neurochaetae; second chaetiger with 6 noto- and 8 neurochaetae.

Anterior dorsal margin of first chaetiger papillated, heavily contracted ventrally. Anterior chaetigers without long papillae. Chaetigers 1–3 all similar in length but third notochaetae posteriorly displaced. Sand cemented anterior shield dorsal, posteriorly rounded, reaching chaetiger 4. Chaetal transition from cephalic cage to body chaetae abrupt; neurohooks start in chaetiger 6. Gonopodial lobes not visible.

Parapodia well developed only in chaetigers 1–2; posteriorly not developed, chaetae emerge from body wall. Parapodia lateral; notopodia lateral, median neuropodia ventrolateral. Notopodia with slightly longer papillae. Neuropodia with smaller papillae. Noto- and neuropodia closer to each other than in other chaetigers. Median notochaetae arranged in a tuft; all notochaetae multiarticulate capillaries, about ¼ as long as body width. Neurochaetae multiarticulate capillaries in chaetigers 1–5; sigmoid simple neurohooks from chaetiger 6, arranged in a transverse line, first neurohooks straight ( Fig. 20B), becoming falcate in median chaetigers ( Fig. 20C), two per bundle, posterior chaetigers with more falcate neurohooks, up to five per neuropodium ( Fig. 20D), in oblique rows.

Posterior end tapering to a blunt cone; pygidium with dorsal anus and 1(–2?) achaetous segments. No anal cirri.

Remarks. Daylithos cinctus ( Haswell, 1892) n. comb. has been regarded as resembling D. parmatus by Haswell (1892:334) and Fauvel (1917:255); however, it is a unique species in the genus because its body is blackish, and its neurohooks are subdistally swollen. These subdistally swollen neurohooks are only present in another species, D. iris , but in the latter the neurohooks are slightly falcate, against markedly falcate in D. cinctus . A neotype has been designated for clarifying the taxonomic status of this species (ICZN 1999, Art. 75.3.1).

The proposed neotype has been described and illustrated (ICZN 1999, Art. 75.3.2, 75.3.3). Haswell (1892) studied two specimens and provided some details; some of which cannot be confirmed, whereas others differ from the neotype. Those that cannot be confirmed are the number of branchial filaments (10), and their size relationship to palps (much shorter). Those that differ are the relative chaetiger where the cauda starts; he stated it was from chaetiger>10 or>20, whereas in the neotype cauda starts after chaetiger 35, but this may depend on what was being indicated, either the first body-width reduction, or the start of the long cylindrical cauda. Haswell did not described the number of transverse rows of papillae but illustrated more than two (Plate 26, Fig. 4); there are 2–3 per segment and the presence of papillae alternate in successive rows. The number of ventral hooks varies along the body; Haswell stated though that there were three corresponding to mid-body chaetigers because the anterior ones have only two whereas the more posterior segments have up to five hooks per neuropodium. Regarding the possible transitional neurohooks, he stated that neurohooks (p. 334) “have a short terminal segment, which is unjointed, curved, and pointed, articulating with the elongated, transversely striated basal portion…” Since there is no illustration of this, one neurohook of chaetiger 7 was removed. It has a distal portion without articulation whereas the handle is multiarticulate, but they are not pseudocompound. The exposed portion is sometimes pseudocompound in other species in the genus, but it is not the case in this species. The specimen had been previously identified as Coppingeria longisetosa , but it is quite different; further, since it has not been recorded after the original description, a neotype would help settle the species definition.

The type material of Haswell is lost ( Day & Hutchings, 1979:83, 133; ICZN 1999, Art. 75.3.4). Because the species has apparently not been found again, and there are two different groups of boring flabelligerids in the region, a redescription together with the designation of a neotype was regarded as adequate, especially because it conforms with what is known about the original material (ICZN 1999, Art. 75.3.5). The original type locality was Watson Bay, Port Jackson, Australia, whereas the neotype locality is Hervey Bay , Central Queensland, Australia. These two localities are far away and have different ecological conditions and this does not follow one of the requirements (ICZN 1999, Art. 75.3.6), but because the species must be redefined, the neotype has been proposed despite this discrepancy. The neotype has been deposited in the Australian Museum (ICZN 1999, Art. 75.3.7) .

Neotype locality. Hervey Bay , central Queensland, Australia.

Distribution. Tropical and subtropical Eastern Australia.