Streblosoma hutchingsae, Lezzi & Giangrande, 2019

Lezzi, Marco & Giangrande, Adriana, 2019, New species of Streblosoma (Thelepodidae, Annelida) from the Mediterranean Sea: S. pseudocomatus sp. nov., S. nogueirai sp. nov. and S. hutchingsae sp. nov., Journal of Natural History (J. Nat. Hist.) 52 (43 - 44), pp. 2857-2873 : 2868-2871

publication ID	https://doi.org/ 10.1080/00222933.2018.1556357
publication LSID	lsid:zoobank.org:pub:7AE78305-6949-46F3-B61A-D93792038F7A
persistent identifier	https://treatment.plazi.org/id/BEC2919B-4CAD-4314-B829-79E02C5D53A3
taxon LSID	lsid:zoobank.org:act:BEC2919B-4CAD-4314-B829-79E02C5D53A3
treatment provided by	Felipe
scientific name	Streblosoma hutchingsae
status	sp. nov.

Treatment

Streblosoma hutchingsae View in CoL sp. nov.

( Figure 6 View Figure 6 , 7 View Figure 7 , 8b View Figure 8 )

Type material

Holotype: Torre Inserraglio , Ionian Sea, Italy, 40.188°’N, 17.925°’E, November 2002, hard bottom, 3 m ( MNCN 16.01 View Materials /17968). Five paratypes: same locality, date and collector as holotype, specimens MNCN 16.01 View Materials /17969; MNCN 16.01 View Materials /17970; MSNP P/4368; MSNP P/ 4369; MSNP P/4370.

Description

Holotype complete, 12 mm long, 0.9 wide, with 48 chaetigers. Two paratypes complete, 7–10 mm long, 0.4–0.6 wide, 41–35 chaetigers. Three paratypes incomplete, 5–6 mm long, 0.4–0.6 wide, 15–60 chaetigers.

Transverse prostomium attached to dorsal surface of upper lip; basal part without eyespots, with sinuate margin ( Figure 6a,c View Figure 6 ). Long and thick buccal tentacles. Peristomium forming lips; upper lip hood-like, twice as wide as long; lower lip buttonlike below mouth ( Figure 6a View Figure 6 ). Segment 1 evident, segment 2 narrow partially covering segment 3 ventrally ( Figure 6a View Figure 6 ). Three pairs of branchiae, on segments 2–4, segment 2 with about two filaments on either side, segment 3 with about two filaments on either side and segment 4 with about two filaments on either side; branchial filaments originating dorsally to notopodia, longest filaments about 2/3 of corresponding body width ( Figure 6b View Figure 6 ), wide mid-dorsal gap within pairs.

Anterior ventral surface glandular until segment 14; glandular surfaces progressively more swollen until segments 4–5 ( Figure 6a View Figure 6 ).

Notopodia starting from segment 2 (first branchiate segment) and extending until segment 23; bilobed notopodia, with flattened lobes; first pair about the same size as following pairs, notopodia progressively shorter towards posterior thorax. Notochaetae arranged in two rows ( Figure 5d View Figure 5 ). Posterior row notochaetae as bilimbate capillaries, slightly inflated at mid-length, and gently tapering towards tip ( Figure 7a View Figure 7 ); anterior row notochaetae shorter than posterior row ones, with similar morphology.

Neuropodia starting from segment 5, slightly raised from surface of body throughout. Uncini in straight rows until chaetiger 13, then conspicuously curved, in C-shaped tori, until posterior body; all with openings towards dorsal side. On mid-body segments, posterior region of the C-shaped row longer than anterior region.

Uncini breviavicular with dorsal button conspicuous, terminal, prow slightly shorter than dorsal button ( Figure 7b,c View Figure 7 ), curved base, main fang conspicuous, secondary teeth in row of two teeth above main fang and a second row with much smaller teeth, one larger tooth inserted between teeth of the first row, surrounded by several (seven or more, not clearly visible at 1000× magnification) smaller teeth at each side (dental formula: MF: 2:8). Dental formula similar through body.

Nephridial and genital papillae not visible.

Pygidium distally rounded, without papillae.

MGS. There is no evident staining pattern; staining homogeneous throughout.

Remarks. Streblosoma hutchingsae sp. nov. is similar to S. duplicata in the absence of eyes and and of a lateral extension of branchiae on chaetiger 1, and in the presence of notopodia until segments 23–24. The two species differ in their dental formula ( S. duplicata MF :2–3:1 vs S. hutchingsae sp. nov. MF: 2:7), as well as in their general aspect: i.e. S. hutchingsae sp. nov. has shorter branchiae, lower lip expanded, segment 2 narrow, partially covering segment 3. No information about differences on the posterior end can be given because S. duplicata was described from an incomplete specimen.

Streblosoma hutchingsae sp. nov. differs from the other species with C-shaped tori in the absence of lateral extensions of branchiae on chaetiger 1 (present in S. hesslei , S. porchatensis , S. toddae , S. uncinata , S. chiguensis , S. wuchiensis , Table 1). It differs from S. curvus and S. nogueirai sp. nov. mainly in the absence of eyes and from S. pseudocomatus sp. nov. in not having notopodia until the posterior body.

Distribution

Endemic for the Mediterranean Sea. This species inhabits rocks near a sewage disposal area in Torre Inserraglio. It was one of the polychaetes collected just in front of the sewage discharges.

Etymology. The new species is named in honour of Dr Pat Hutchings, who has contributed to the understanding of Terebellidae systematics.

Key for Mediterranean species of Streblosoma View in CoL

1. Uncini in C-shaped loops from mid-thorax .............................................................................. 2 No uncini in C-shaped loops from mid-thorax........... ........... S. bardi (Malmgren 1866)

2. Notopodia not extending until posterior body ...................................................................... 3 Notopodia until posterior body......................... ......................... S. pseudocomatus View in CoL sp. nov.

3. Eyes absent.................................................................................................. S. hutchingsae View in CoL sp. nov. Eyes present...................................................................................................... S. nogueirai View in CoL sp. nov.