Dichogaster

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 : 398-399

Dichogaster sp. 4

Material examined. 3 juveniles, Savane Mulet, Basse Terre, Guadeloupe, N16°02.348', W61°39.965', 1178 m asl. In organic soil, moss and root mats in low montane vegetation of the western slope of Soufriere volcano.

Description. Dimensions 45–50 mm by 3 mm at x, 2.5– 3 mm at xxx; body cylindrical in cross section, segments 174, 177, unpigmented. Setae ventral, closely paired throughout; setal formula AA:AB:BC:CD = 5:1:4:1 at xxx; DD> 1/2 circumference throughout. Prostomium epilobous closed, segments faintly triannulate from segment lx onwards. First dorsal pore 12/13, 14/15, spermathecal pores in AB 7/8, 8/9. Ovipores on equatorial ovate papillae median to A in xiv; male pores not seen; prostatic pores and penial setae at ends of S-curved seminal grooves in AB in xvii–xix. Clitellum not developed; no other genital markings.

Septa thin until 9/10–12/13, 9/10/11 meet body wall at same point; alimentary canal with small proventriculus in v, two gizzards in vi, vii; esophagus valvular in xviii, intestinal origin xix; typhlosole 23/24–cxxv, or –cxxxiii, a low fold 0.25 lumen diameter. Paired lateral typhlosoles 24–26, 29; very small. Thick chloragogen coating on outer intestinal surface from xxv–lv, intestinal constriction at 54/55; no caeca. Calciferous glands reniform, paired in xv– xvii, composed of longitudinally-oriented lamellae opening to medial, glands opening by separate ducts to esophagus, gland size xv<xvi≤xvii. Micronephridia 10 per segment, pre-intestinal nephridia tubular; intestinal segment nephridia closed sac-shaped with oil droplets. Vascular system with ventral trunk, single dorsal trunk, these connected by lateral commisural vessels in v(?), vi–ix, vii to gizzard wall; latero-esophageal hearts in x–xii.

Fan-shaped ovaries composed of long strings, with funnels in xiii; paired spermathecae in viii, ix, very small in juvenile condition. Male sexual system undeveloped, tubular prostates xvii, xix very small in juvenile condition, as are penial setal follicles.

Remarks. There are several smaller juveniles apparently of this species in the collection but here we are reporting on the largest individuals. However incomplete the description is, this species can be distinguished from others of Guadeloupe quite easily. There are 3 acaecate species described above, all of which are pigmented. In James (1996) there are four acaecate species, and all are obviously pigmented, either blue-green or red to redbrown. One of those, D. musciphila plus another presented above as D. sp. 1 was found at the same location. All four species in James (1996) are tanylobous, have longer lateral typhlosoles and either more (12-14) or fewer (8) nephridia per segment. A fifth species in the acaecate group, left undescribed in James (1996) is epilobous, has 12 nephridia and is blue-green in life.