Grania simonae, Prantoni & Wit & Erséus, 2016

Prantoni, Alessandro Lívio, Wit, Pierre De & Erséus, Christer, 2016, First reports of Grania (Clitellata: Enchytraeidae) from Africa and South America: molecular phylogeny and descriptions of nine new species, Zoological Journal of the Linnean Society 176 (3), pp. 485-510 : 495-497

GRANIA SIMONAE SP. NOV.

FIGURE 6

Holotype

SAMC A82476, CE14111 , whole-mounted, sexually mature specimen, 11 posterior segments amputated, from Van Dyks Bay , Overberg District , Overstrand Local Municipality, Province of the Western Cape, South Africa, 34°37′00″S, 19°21′21″E, intertidal crevice between rocks. Collected by N. Bekkouche, 16 December 2011. COI barcode sequence, GenBank acc. no. KT428100 ; for other sequence data, see Table 1 .

Etymology

Named for the South African annelid specialist, Dr Carol Simon, who arranged and generously assisted with the workshop/fieldwork that led to the collection of this species.

Paratypes

Six whole-mounted, sexually mature specimens, all from the type locality and date, and collected by N. Bekkouche. SAMC A82482, complete, not DNA barcoded specimen. SAMC A82477, CE14110 , with 14 midbody segments amputated. SAMC A82478, CE14112 , with 14 middle body segments amputated. SAMC A82479, CE14058 , with some segments amputated. SAMC A82480, CE14060 , with eight posterior segments amputated. SAMC A82481, CE14093 , with some segments amputated, from the type locality too, but in shallow subtidal. For COI barcodes of paratypes, see Table 1 .

Description

Body of only complete specimen 16 mm long, 79 segments (paratype SAMC A82482), 0.16–0.20 mm wide at segment III, 0.15–0.22 mm wide at segment XII (n = 7). Prostomium rounded, 55–87 μm long, 62– 80 μm wide, epidermis 7–10 μm thick (n = 7), not reduced at front tip. Ventral chaetae present from segment IV, lateral chaetae absent. Chaetae ( Fig. 6A ) L-shaped, 45–90 μm long, 5–6 μm thick at midpoint, shaft straight and broad at the base, foot 16–20 μm long, with slight heel, and sometimes with slight toe. Chaetal index ( Rota & Erséus, 2003) 4.70 ± 0.39 (n = 5). Free chaetae scattered in the coelomic cavity, sometimes numerous. Epidermal gland cells inconspicuous. Clitellum maximally 22 μm thick, extending from segments XII to XIII, comprising rows of large granular cells, absent between male pores. Spermathecal pores in lateral lines, immediately posterior to 4/5. Male pores located ventrolaterally in mid-segment XII. Female pores not observed.

Brain posteriorly indented. Head organ (sensu Rota & Erséus, 1996) absent. Pharyngeal glands in segments IV–VI, dorsal lobes in segment IV (one pair), in segment V (one pair), and in segment VI (one pair), ventral lobes present in segment IV (one pair), in segment V (two pairs), and in segment VI (two pairs); glands not connected dorsally. Nephridia not observed. Chloragogen cells from segment VII distinctive, containing dark granules, dense in posterior segments. Dorsal blood vessel from segments XXI or XXIV (n = 3). Coelomocytes irregular, at least 10 μm wide, most abundant posteriorly (in complete specimen) ( Fig. 6C ). Sperm sac extending into segment XVI, egg sac reaching segment XX. Sperm funnels in segment XI about two times longer than wide, folded, occasionally directed posteriorly (holotype) ( Fig. 6D ). Vasa deferentia reaching at least segment XIV, coiled, internally ciliated, 15 μm wide near sperm funnel, narrowing to about 10 μm. Glandular penial bulb type 1 (sensu Coates, 1984), 75–80 μm long, 50–68 μm wide (n = 6); stylet absent ( Fig. 6D ). Copulatory gland (in segment XIV) absent. Spermathecal ampulla small, more or less spherical, 37–55 μm long, 37–52 μm wide ( Fig. 6B ). Sperm rings up to 15 μm wide. Ectal duct slender, 90–115 μm long, 17–25 μm wide, not narrowing at ends. No gland at spermathecal pore.

Remarks

Grania simonae sp. nov. is unique among the South African species described here and all other members of the genus by the combination of the following characters: lack of lateral chaetae, spermathecae with small and spherical ampulla, dense chloragogen cells, dorsal blood vessel commencing in segment XXIV, and absence of head organ and a midventral copulatory gland in segment XIV. This is the only South African species with numerous and conspicuous coelomocytes scattered throughout the body, but as stated by Rota et al. (2007) and De Wit & Erséus (2007), the apparent lack of coelomocytes in the other species described herein may be an artifact, caused by the fixation and staining procedures.

The absence of lateral chaetae has been recorded for at least 13 different species of Grania to date. Among them, G. simonae sp. nov. is reminiscent of the Antarctic species Grania carchinii Rota & Erséus, 1996 , by the absence of penial stylets and head organ, and the possession of dense chloragogen cells; however, the adult specimens of G. simonae sp. nov. are at least twice as large as those of G. carchinii known so far. These two species are also distinguished from each other by the morphology of the spermatheca. Grania carchinii has a larger (pear-shaped) spermathecal ampulla and a shorter spermathecal duct than G. simonae sp. nov.; the latter has a spherical spermathecal ampulla. Moreover, G. carchinii has a midventral copulatory gland in segment XIV, which is lacking in G. simonae sp. nov.

The Western Australian G. conjuncta and G. vacivasa also resemble G. simonae sp. nov. by the absence of lateral chaetae, stylets, and head organ, but they both differ from the latter by possessing a midventral copulatory gland in segment XIV and by extremely long sperm funnels; the funnels are only about twice longer than wide in G. simonae sp. nov., but 19 times longer than wide in G. conjuncta , and 11–15 times longer than wide in G. vacivasa .

Figures

Figure 6. Grania simonae sp. nov. A, chaetae. B, spermatheca. C, coelomocytes. D, penial bulb and sperm funnel. See text for abbreviations.