Hesione mooreae, Salazar-Vallejo, 2018

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325 : 272-274

Hesione mooreae n. sp.

( Fig. 28 )

urn:lsid:zoobank.org:act:1862BD5B-7FA6-49AD-9A24-05F9D55B429E

Hesione genetta – Willey 1905: 267. — Fauvel 1919a: 337; 1953b: 105 (non Grube, 1867).

TYPE MATERIAL. — Indian Ocean. Red Sea. Holotype, UF 3485 , Saudi Arabia, Farasan Islands , Mahama Island (16.4892, 41.94432; 16°29’21.1200”N, 041°56’39.5520”E), sand, reef, rubble fringing slope, 4-17 m depth, 9.III.2013, A. Anker, P. Norby & G. Paulay coll.

ADDITIONAL MATERIAL. — Indian Ocean. Red Sea. 1 specimen, UF 3624 , Saudi Arabia, Al Lith (20.116983, 40.214939; 20°07’01.1388”N, 040°12’53.7804”E), Whale Shark Reef, 10 m depth, 22.III.2013, A. Anker, P. Norby & J. Moore coll. [body twisted, distorted by torsion, a small posterior region fragment removed for molecular analysis; pigmentation pattern including brownish transverse bands and spots along dorsum, with a wider band on chaetiger 2, but no bands on chaetigers 1 and 3; pharynx exposed, distorted, dorsal papilla not seen; acicular lobe double, upper tine twice longer than lower one] .

Madagascar. 1 specimen, MNHN-IA-PNT91e (formerly jar 70), Nosy-Bé reefs, 27.V.1898, F. Geay coll. [31 mm long, 3.5 mm wide; complete, bent backwards; pigmentation brownish, including round dots and dorsal, irregular transverse bands, wider, better defined in chaetiger 1, missing in chaetiger 2, thinner, poorly defined in following chaetigers; acicular lobes double, tines of similar size]. ETYMOLOGY. — This species is being named after Jenna Moore , from the University of Florida , Museum of Natural History , Gainesville, in recognition of her many sampling efforts on polychaetes, especially on hesionids, and for her kind support and help for molecular analysis of many hesionid samples. The name is a noun in genitive ( ICZN 1999 : art. 31.1.2).

DISTRIBUTION. — Western Indian Ocean, Red Sea to India (previous records), and Madagascar, 4-17 m depth, sand or mixed bottoms.

DIAGNOSIS. — Hesione with prostomium rectangular; parapodia with dorsal cirri basally cylindrical, dorsal cirrophore 1-2 times as long as wide; larger acicula blackish; acicular lobe double, tines digitate, upper one twice longer than lower one; neurochaetal blades bidentate, 2-5 times as long as wide; subdistal tooth as large as distal one, with guards approaching subdistal tooth.

DESCRIPTION

Holotype, UF 3485, complete, strongly bent dorsally. Pigmentation pattern including brownish, dorsal transverse bands and irregular spots ( Fig. 28A ); transverse bands better defined along most chaetigers, but none in chaetigers 2 and 16; chaetiger 1 with a wide band perfectly defined along anterior and posterior margins, 3-4 times longer than band in chaetiger 3 ( Fig. 28 B-D); following chaetigers with slightly less defined bands. Pigmentation extended into prostomium and pharyngeal basal ring, lateral cushions; tentacular cirri, dorsal cirri and neuropodial lobes whitish in ethanol. Body subcylindrical, 26 mm long, 4 mm wide.

Prostomium slightly as wide as long, anterior margin expanded anteriorly, lateral margins rounded, posterior margin with a shallow notch, 1/5 as long as prostomium, with irregular brownish spots. Antennae digitate, 4-5 times as long as wide, or longer than interocular distance. Eyes brownish, anterior ones slightly larger and more separated from each other than posterior ones ( Fig. 28C, D ).

Tentacular cirri thin, most twisted, longest ones reach chaetiger 8. Lateral cushions low, some divided into 2 sections.

Parapodia with chaetal lobes tapered, truncate ( Fig. 28E ); dorsal cirri with cirrophores 1-2 times as long as wide, cirrostyles basally cylindrical, smooth medially, annulated distally, as long as body width (excluding parapodia); ventral cirri irregularly contracted, surpassing chaetal tips.

Neuraciculae blackish, three of different width, thinner one paler. Acicular lobe double, digitate, upper tine twice longer than lower one ( Fig. 28D [inset]).

Neurochaetae about 20 per bundle, blades bidentate, 2-5 times as long as wide; blades aligned at a certain angle from handle, teeth of similar length, subdistal tooth usually wider, guard thick, approaching subdistal tooth ( Fig. 28F ).

Posterior region tapered into a blunt cone ( Fig. 28G ); pygidium smooth, anus with seven low, blunt papillae.

Pharynx partially exposed; dorsal papillae not seen. Oocytes not seen.

Pigmentation

Living specimens with transverse, irregular bands throughout body over a variable background, being whitish anteriorly, becoming pinkisk medially, and pale pink posteriorly ( Fig. 28A ). Transverse bands reddish-brown in living specimens becoming brownish once preserved; bands postioned slightly behind neuropodial region, extended into lateral cushions but no band in chaetiger 1 and rather poorly defined in chaetiger 3, following chaetigers with bands irregularly defined, poorly defined in chaetiger 15, indistinct in chaetiger 16. Prostomium mottled and a few round spots in tentacular segments. Eyes reddishbrown alive, becoming brownish once preserved. Tentacular cirri and dorsal cirri pale brown; neuropodial lobes whitish.

REMARKS

Hesione mooreae n. sp. groups with H. genetta Grube, 1867 and H. paulayi n. sp. by having long-lasting pigmentation, including transverse brownish bands. As indicated in the key below, H. genetta has its largest transverse band in chaetiger 2, whereas both H. mooreae n. sp. and H. paulayi n. sp. have them on chaetiger 1. There are two main differences between the latter two species; in H. mooreae n. sp. the posterior margin of the largest band is as well defined as its anterior margin, and its longest tentacular cirri reach chaetiger 8, whereas in H. paulayi n. sp. the posterior margin of its largest band is not well-defined, and the longest tentacular cirri reach chaetiger 6.

Figures

FIG. 28. — Hesione mooreae n. sp., holotype, UF 3485, alive: A, dorsal view; B, anterior region, dorsal view; preserved; C, right lateral view; D, anterior end, dorsal view, pressed by glass slide, close-up of head, pharynx and first three chaetigers; E, chaetiger 8, right parapodium, anterior view (inset: acicular lobe); F, same, neurochaetal blades; G, posterior region, pressed by glass slide fragment. Scale bars: A, 2 mm, B, 1.3 mm, C, 0.9 mm; D, 1.4 mm; E, 0.3 mm; F, 20 µm; G, 1.5 mm (photos A, B, G. Paulay).