Grania papillata Wit & Erséus, 2007, sp.n.

Grania papillata sp.n.

(Figure 7 –8, Table 1)

Holotype: SMNH type coll. 6599, whole-mounted specimen from Lifou, stn. NC00-35.

Paratypes: SMNH type coll. 6600-6602, 3 whole-mounted specimens from Lifou, 1 of which from stn. NC00-12 and 2 from stn. NC00-25; SMNH type coll. 6603-6606, 6608-6609, 6 whole-mounted specimens from Touho, 2 of which from stn. NC93-50 and 1 each from stns. NC93-37, NC93-54, NC93-59 and NC93- 61.

Other material examined: SMNH main coll. 88001-88003, 3 specimens from Lifou (type locality and stn. NC00-25); SMNH main coll. 88004-88076, 73 specimens from Touho (stns. NC93-23, NC93-24, NC93- 31, NC93-33, NC93-34, NC93-37, NC93-50, NC93-53, NC93-54, NC93-55, NC93-56, NC93-59, NC93-60, NC93-62, NC93-69, NC93-70, NC93-72, NC93-73).

Description of type material: Body 9.4–13.1 mm long (n=10), 0.16–0.20 mm wide at III, 0.17–0.22 mm at clitellum (n=10). Segment number 62–82 (n=10). Prostomium rounded, 75–110 μm wide, 55–80 μm long (n=10); epidermis 17–25 μm thick on occipital lobes and upper lip (n=7), 8–20 μm thick at front side (n=10).

Peristomium 133–185 μm wide at 1/2 (n=10). Ventral chaetae commencing in V, absent in XII; laterals completely absent. Preclitellar chaetae 60–80 μm long, post-clitellar chaetae of uniform length, 85–100 μm long (n=16); chaetae L-shaped with distinct heel, sharply pointed, foot 20–25 μm long (chaetal index=3.40, n=16, sd=0.25) (Figure 7 A). A pair of conspicuous body wall papillae present ventrolaterally in mid-V in all specimens, extending 35–45 μm from epidermis, 15–20 μm wide at base (Figures 7 B; 8). Epidermal gland cells conspicuous in I–IV only, interspersed irregularly. Clitellum 10–23 μm thick, starting at anterior end of XII and extending to chaetal position of XIII, consisting of granular gland cells interspersed irregularly with hyaline cells at a ratio of about 2:1 (Figure 7 C), except around male pores where hyaline cells are absent, only forming regular rows at anterior and posterior end of clitellum. “Copulatory glands” not observed in XIV. Spermathecal pores lateral, immediately behind 4/5. Male pore ventrolateral in mid XII.

Interference contrast microscopy photo of epidermal papilla of G. papillata.

Brain in II–III, posteriorly indented in “head” region. Head organ absent. Pharyngeal glands located from 4/5 to 6/7, not united dorsally; dorsal lobes present in IV–VI, ventral lobes present in IV (1 pair), V (2 pairs) and VI (2 pairs); ventral lobes in V compressed ventrally (Figure 7 D). First pair of nephridia at 7/8. Dorsal blood vessel commencing in XXXVIII– XLII (n=7). Chloragogen cells small (5–7 μm tall). Coelomocytes abundant, oval (10–12 μm long), cytoplasm coarsely granular, nuclei unstained. Sperm sac extending posteriorly from clitellum as far back as XIX. Sperm funnels of uniform width, 40–60 μm wide, 4–5 times as long as wide. Heads of spermatozoa 20 μm long. Vasa deferentia long, loosely coiled posteriorly from XII to XV– XVIII; 7 μm wide, internally ciliated. Penial apparati (Figure 7 E) with oval, uniform glandular structures, 100–120 μm long, 65–85 μm wide, surrounding smaller, sac-like invaginations of epidermis at male pores, 10 μm wide, 60–70 μm deep (Penial bulb type 3). Stylets absent. Egg sac ending as far back as XXIII. Spermathecae (Figure 7 F) large, attached to oesophagus near 5/6; ampullae, sac-like, 75–120 μm long, 50–70 μm wide, lumen funnel-shaped at ectal end; ectal ducts thick-walled and covered by muscle cells, uniform in diameter (30–45 μm), 60–80 μm long; 4–7 sperm rings per spermatheca, 13–18 μm in diameter, located in inner end of ampullae, as well as large bundles of spermatozoa in free form throughout ampullae; ectal glands on spermathecal ducts absent.

Etymology: Named after the characteristic papillae in segment V, which have only been observed in this species.

Remarks: This species is easily distinguished from all members of this genus described to date by the paired ventrolateral papillae in V (Figure 8). These papillae do not seem to be attached to any muscle tissue internally, nor do they seem to be connected to any glandular tissue (see Discussion). The spermathecae which fill almost all of V are also unique to this species and are very easy to identify with their large, sac-like ampullae and muscular ectal ducts. Muscular ectal ducts have been described previously, in G. longiducta Erséus & Lasserre 1976, but in that species they are long and narrow, while in G. papillata the ectal ducts are much wider and shorter. Grania papillata can also be discerned from other members of this genus in that its vas deferens is coiled as far back as XVIII, and the egg sac stretches as far as XXIII, which has previously only been reported for a few North and West Australian Grania species (G. vacivasa Coates & Stacey, 1993, G. conjuncta Coates & Stacey, 1993, G. eurystila Coates & Stacey, 1997 and G. integra Coates & Stacey, 1997).

The dorsal blood vessel location is interesting in that it commences further back (XXXVII–XLII) than has been reported for most species of the genus. The only instance where something similar has been noted is in G. dolichura Rota & Erséus, 2000, a Tasmanian species, in which the dorsal blood vessel commences in XXX- VIII–LXXVIII. Furthermore, G. papillata possesses large epidermal cells in I–IV, creating an uneven body surface in these segments. This is not the case for any other species described in this paper, but it resembles a species described from Tasmania, G. dolichura Rota & Erséus, 2003. The structure of G. papillata ’s clitellum also suggests a relationship with the Tasmanian species, since the irregular form is unique in the New Caledonian taxa, yet shared with G. t a s m a n i a e, as well as with G. antarctica Rota & Erséus, 1996, G. c a rc h i n i i and G. hirsuticauda, all from Antarctic waters.

Distribution and habitat: Touho area, New Caledonia, and Lifou, Loyalty Islands, lower intertidal and subtidal (22 m), heterogeneous sand.