Grania fustata, Wit, Pierre De & Erséus, Christer, 2007

Wit, Pierre De & Erséus, Christer, 2007, Seven new species of Grania (Annelida: Clitellata: Enchytraeidae) from New Caledonia, South Pacific Ocean, Zootaxa 1426, pp. 27-50 : 40-42

Grania fustata sp.n.

( Figure 6 , Table 1)

Holotype: SMNH type coll. 6589, whole-mounted specimen from Touho, stn. NC93-9.

Paratypes: SMNH type coll. 6590-6598, 9 whole-mounted specimens from Touho, 4 of which from stn. NC93-8, 2 from type locality, and 3 from stn. NC93-10.

Other material examined: SMNH main coll. 87982-87999, 18 specimens from Touho (type locality, and stns. NC93-8 and NC93-10).

Description of type material: Body 12.1–15.3 mm long (n=10), 0.25–0.28 mm wide at III, 0.24–0.27 mm at clitellum (n=10). Segment number 61–71 (n=10). Prostomium rounded, 120–140 μm wide, 65–85 μm long (n=10); epidermis 25–28 μm thick on occipital lobes, 18–23 on upper lip, 8–13 μm at front side (n=9). Peristomium 205–225 μm wide at 1/2 (n=10). Ventral chaetae commencing in V, absent in XII; lateral chaetae commencing in XXII–XXIV. Chaetae stout, of uniform size throughout body, 100–140 μm long (n=16); chaetae L-shaped, sharply pointed, foot 20–33 μm long, with slight heel (chaetal index=4.54, n=16, sd=0.67) (Figure 6A). Epidermal gland cells inconspicuous, interspersed irregularly. Clitellum 20–25 μm thick, starting at anterior of XII and extending to chaetal position of XIII, consisting of uneven transverse rows of granular gland cells irregularly interspersed with smaller hyaline cells at a ratio of around 2:1 ( Figure 6 B) except around male pores where hyaline cells are absent. “Copulatory glands” present ventrally in XIV. Spermathecal pores lateral, located immediately posterior to 4/5. Male pores ventrolateral in XII.

Brain in II–III, posteriorly indented in “head” region. No true “head organ” present, but bilobed vesicle present immediately behind 0/1, dorsal to the anterior furcation of blood vessel, between circumpharyngeal commissures; no inclusions present, but hollow compartments visible which seem to be internally ciliated. 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) ( Figure 6 C). First pair of nephridia at 7/8. Dorsal blood vessel commencing in XXVI–XXIX (n=10). Chloragogen cells small (extending 5–7 μm above gut wall). Coelomocytes abundant, flattened, circular to slightly oval in shape with irregular surfaces, about 15 μm in diameter, granular with stained nuclei. Sperm sac extending posteriorly from clitellum as far back as XXI. Sperm funnels of uniform width, 50–60 μm, 3 times as long as wide. Heads of spermatozoa about 15–17 μm long. Vasa deferentia long, loosely coiled in XII and XIII, 5 μm wide, internally ciliated. Penial apparati (Figure 6D) granulated oval structures, 80–95 μm long, 50–70 μm wide, each consisting of glandular body surrounding invagination of epidermal tissue at male pore; epidermal invagination forming large aglandular sac 15–20 μm wide, 70–90 μm deep (penial bulb type 3). Stylets absent. Egg sac extending as far back as XXI– XXIV. Spermathecal ampullae ( Figure 6 E) rounded, 50–55 μm in diameter, ectal ducts bipartite, with ental parts cylindrical, 35–40 μm long and 10–15 μm wide, ectal ends bulbous, 25–30 μm thick at widest point; 4– 5 sperm rings per spermatheca, 10–20 μm in diameter, located throughout ampullae; ectal glands on spermathecal ducts absent.

Etymology: Named using the Latin word fustus and the suffix – ata, which translates into “armed with a club”. This refers to G. fustata being equipped with penial bulbs with large aglandular sacs which are often everted in mounted specimens.

Remarks: The shape of the spermathecal ectal duct of G. f u s t a t a, with a bulbous ectal part and a narrow ental part, is rather unusual in this genus. A similar feature has been described for G. l a x a r t a Locke & Coates, 1990, known from the Atlantic waters of Bermuda and Belize. Grania fustata is different from G. l a x a r t a, however, in that its penial bulbs lack stylets, but rather have large epidermal invaginations at the male pores.

As in G. novacaledonia sp.n. and G. c i n c t u r a sp.n., G. f u s t a t a possesses a bilobed vesicle anterior to the brain which contains hollow compartments, but no inclusions as a head organ proper would have (see Remarks under G. novacaledonia ; and Discussion). Other characters shared with G. c i n c t u r a are the bipartite spermathecal ectal ducts, and the large size, although G. fustata clearly is the larger of the two. Grania fustata also differs from G. cinctura in lacking glandular cells around the spermathecal ectal duct, and in the larger size of the epidermal invaginations at the male pores.

Distribution and habitat: Touho area, New Caledonia, lower intertidal to barely subtidal, heterogeneous sand.

Figures

FIGURE 6. Grania fustata sp. n.. A: Chaetae. B: Clitellar cell pattern. C: Overview of I – VII. D: Penial apparatus. E: Spermatheca.