Malmgreniella inhacaensis Pettibone 1993

Malmgreniella inhacaensis

Harmothoe lunulata.—Day, 1962:629 [not Delle Chiaje, 1830].

MATERIAL EXAMINED.—INDIAN OCEAN: Mozambique: Inhaca Island, Delagoa Bay, 25°50′S, 32°50′E, University of Cape Town Ecological Survey (IN 145A), commensal in burrows of Balanoglossus sp. and Ptychodera sp., holotype (BMNH 1963.1.4, as Harmothoe lunulata by Day, 1962).

DESCRIPTION.—Length of holotype 17 mm, width 5 mm including setae, 37 segments, last segment minute. Body flattened, tapering slightly anteriorly and posteriorly, with 2 transverse ciliated bands per segment. Ventral surface of posterior region with brown transverse bands. Eltyra 15 pairs, on usual segments, oval to subreniform, with rather large group of microtubercles on anterior part beginning on 2nd elytra, fewer in number on posterior elytra, and with some scattered micropapillae on surface; brown pigmentation pattern consisting of transverse bands and bands along medial and posterior borders (Figure 13B–E).

Bilobed prostomium with lobes truncate, without peaks; anterior pair of eyes anterolateral, nearly hidden from view dorsally, smaller posterior pair posterodorsal; ceratophore of median antenna large, in anterior notch of prostomium, style missing; lateral antennae with ceratophores inserted terminoventrally, with styles short, subulate, with short papillae; palps stout, tapered; tentaculophores lateral to prostomium, each with single seta on inner side and long tapered papillate dorsal and ventral tentacular cirri (Figure 13A). Segment 2 with first pair of large elytrophores, biramous parapodia, and long ventral buccal cirri similar to tentacular cirri; notosetae similar to those of following parapodia; neurosetae more slender than following, with entire and bifid bulbous tips (Figure 13F,G).

Biramous parapodia with notopodia much shorter than neuropodia, rounded with projecting acicular lobes on lower sides; larger neuropodia with subconical presetal acicular lobes with thick supraacicular processes and shorter, rounded postsetal lobes (Figure 13H,I). Notosetae very numerous, of several lengths, forming spreading bundle, about as stout as neurosetae, with numerous spinose rows and tapered to rounded tip (Figure 13J). Neurosetae numerous, forming fan-shape bundle, upper ones with longer spinose regions and long slender secondary tooth; middle and lower ones with shorter spinose regions and shorter secondary tooth (Figure 13K). Dorsal cirri with cylindrical cirrophores; styles with short papillae and filamentous tips extending to about tips of neurosetae; dorsal tubercles bulbous; ventral cirri short, tapered, with short papillae (Figure 13I). Pygidium with dorsal anus medial to parapodia of posterior small segment, with pair of long anal cirri.

BIOLOGY.—Malmgreniella inhacaensis is found living commensally in the burrows of the enteropneusts Ptychodera and Balanoglossus.

ETYMOLOGY.—The species is named for the collection site of Inhaca Island.

DISTRIBUTION.—Indian Ocean, Mozambique, Inhaca Island.