Dichogaster etaspiqui, James, Samuel W. & Gamiette, Franciane, 2016

James, Samuel W. & Gamiette, Franciane, 2016, New species of Dichogaster Beddard, 1888 (Clitellata: Benhamiidae) with additional records of earthworms from Guadeloupe (French West Indies), Zootaxa 4178 (3), pp. 391-408 : 395-396

Dichogaster etaspiqui n. sp.

( Fig. 3 A–D)

Holotype. MNHN HEL 594 adult, Montane forest adjacent to Etang As de Piques in bromeliad leaf axils, Capesterre, Basse Terre, Guadeloupe, N16°01.410', W61°38.562', 782 m asl.

Paratype. MNHN HEL595, adult, from type locality.

Other material. Several live specimens retained in culture experiments.

Etymology. The name etaspiqui is derived by contracting some syllables of the site name, Etang As de Piques, which translated to English, is Ace of Spades Pond.

Description. Dimensions 55–61 mm by 2.5 mm at segment x, 3 mm at xxx, 2.5–3 mm at clitellum; body slightly dorso-ventrally ovate, segments 107–115. Setae all ventral, closely paired throughout; setal formula AA:AB:BC:CD= 2:1:2:1 at xxx; DD ≥ 2/3 circumference. Prostomium prolobous or very short closed epilobous, gray-blue pigmentation darker anteriorly; faded in formalin preservation. First dorsal pore 9/10; spermathecal pores on trailing edges of vii, viii next to 7/8/ 9 in A. Ovipores equatorial median to A in xiv on circular papilla; male pores not seen; prostatic pores at ends of laterally concave grooves in A within elevated hourglass-shaped zone in xvii–xix. Clitellum xii–xxi saddle shaped, no other genital markings ( Fig. 3 A,B).

Septa 10/11–12/13 very slightly muscular, many trans-septal muscles from pharynx to body wall in viii. Alimentary canal with proventriculus in v, two weak gizzards in vi, vii; esophagus valvular in xviii, intestinal origin xix, full size in xx; typhlosole a simple low ridge originating in xxix, ending xlvii; paired small dorsal caeca in xlv, xlvi, or xlvii. Calciferous glands reniform, paired in xv–xvii, composed of longitudinally-oriented lamellae opening to medial lumen; glands of xv with separate ducts to esophagus; glands of xvi, xvii ducts join in small sinus before merging with esophageal lumen, glands xv<xvi<xvii. Micronephridia 6 per segment, pre-intestinal nephridia tubular; intestinal segment nephridia closed sac-shaped, thickly mantled; ventral rows of intestinal segments with nephrostomes; dorsal row bilobed; no nephrostomes seen anteriorly; nephridia distributed ABdorsum. Vascular system with ventral trunk, single dorsal trunk, these connected by commisural vessels in viii, ix, latero-esophageal hearts in x–xii, those of xi, xii very large. Commissural vessel of vii to gizzard.

Ovaries in xiii; paired spermathecae in viii, ix, axis tripartite consisting of long S-curved duct, expanded central chamber and terminal ovate ampulla; sub-spherical sessile diverticulum attached at boundary of duct and central chamber ( Fig. 3 C). Male sexual system holandric, testes and funnels free, seminal vesicles small xi, xii; tubular prostates xvii>xix, xix extending into xviii, duct very short, gland nearly sessile. Penial setae and setal follicles very long, about 2.5 mm, tapering to fine point in the distal 0.4 mm; ornamentation only small serrations ( Fig. 3 D).

Remarks. Extensive review of similarities of the caecate Guadeloupe Dichogaster species described in James (1996) to certain characters found in African species concluded that the 1996 species were new and distinct from the African group. The same general distinctions with African species apply here. Dichogaster etaspiqui is most similar to D. arborea James, 1996 but lacks the midventral genital markings of that species, has a more extensive clitellum, the calciferous gland ducts of xvi and xvii joined, a rudimentary typhlosole, and a more anterior location of the caeca. The two species with similar calciferous gland ducts ( D. callaina and D. girija James, 1996 ) both have 8 nephridia and very different typhlosole placements.

The following Dichogaster specimens are each represented by a singleton specimen or by juveniles only in the aggregated collections. We are providing a brief description of each and hope that future collecting will produce more individuals.

Figures

FIGURE 3. Dichogaster etaspiqui n. sp. A. Dorsal view, live photo. B. Ventral view, clitellum region and spermathecal pores. C. Spermathecae. D. Tip of penial seta.