Belladrilus Righi, 1984

James, Samuel W., Bartz, Marie L. C. & Brown, George G., 2023, New Ocnerodrilidae genera, species and records from Brazil (Annelida: Crassiclitellata), Zootaxa 5255 (1), pp. 235-269 : 252-254

Belladrilus Righi, 1984

Type species: B. jimi Righi, 1984

Diagnosis: Small Ocnerodrilidae with no dorsal pores, one pair of prostatic pores in xvii, and one of male pores in 17/18 or with seminal grooves in 17/18-xviii. Gizzard present or not in vii, one pair of calciferous glands in ix, testes and male funnels in x. One pair of tubular prostatic glands in xvii, spermathecae without diverticula. Endemic to Latin America, found in Paraguay, Argentina and Brazil, where most (6) of the known species (9) occur ( Christoffersen 2008). Belladrilus Righi, 1984 was divided into subgenera Belladrilus (Belladrilus) and Belladrilus (Santomesia) Righi, 1984 on the basis of the structure of the calciferous glands ( Righi 1984). The nominate subgenus has glands with a single central cavity, while the other has glands with several approximately longitudinal canals. Based on the calciferous gland structure, the two new species fall in Belladrilus (Belladrilus) .

Belladrilus (Belladrilus) riparius James, Bartz & Brown , sp. nov. ( Fig. 11 a-c)

Holotype. BRSP0922 , one adult, Boracéia Biological Station of the University of S„o Paulo ( USP), S„o Paulo state, Brazil, S23.654003°, W 45.888603°, 840 m asl., in wet margins of a river; 21 April 2004, G.G. Brown and S.W. James, colls.

Paratypes. BRSP0202 , 19 adults of which 4 were dissected, same data as holotype .

Etymology. The species is named for its collection location at the edge of a river.

Description. Dimensions 47-62 mm by 1.4-1.5 mm at segment x, 1.3-1.5 mm at clitellum, 1.2-1.3 mm at xxx, body cylindrical, segments 125-134. Setae closely paired throughout, CD above lateral; setal formula AA:AB:BC: CD = 3:1:4:1 at x, 4.5:1:7:1 at xxx, DD <½ circumference. Prostomium broad epilobous open; segments lacking secondary annulations, tapering to a fine point starting at lxxxv-xc, pygomere elongate conical. Unpigmented, no dorsal pores, spermathecal pores large sphincter-like openings within 7/ 8 in AB. Ovipores in xiv in B midway between equator and 13/14; male pores equatorial in xviii deep within ends of seminal grooves; prostatic pores in xvii at apex of elevated papillae at ends of grooves; seminal grooves extend from male pores to xvii, and continue up the prostatic pore papillae. Setae AB not visible in xvii-xix. Clitellum in xiii-xxi, annular in xiii-xvi, xx, xxi or almost annular lacking a thin mid-ventral strip; genital markings mid-ventral within AA, post-setal in xvi, pre- and partly post-setal in xix ( Fig. 11a, b ).

Septa 5/6-8/9 muscular, 9/10-10/11 less so. Alimentary canal with gizzard in vii; long muscle strands from pharynx to body wall over v-viii; esophagus valvular in xi, ½ xii, intestinal origin in xii – ½ xii, full diameter in xiii, laterally pouched in xii-xv; no typhlosole. Calciferous glands oblong, paired in ix, with solid thick walls surrounding central lumen either slit-like in cross section or irregular ( Fig. 11c ); each gland with blood vessel from anterior end to extra-esophageal vessel, and blood vessel from posterior end of gland to supra-esophageal vessel. Holonephric, first nephridia in segment xii, attain full size and regular morphology in xiii; tubular throughout; tubules bound in broad flat membrane sac covering most of segment length but not thick and glandular in appearance; no bladders.

Vascular system with ventral trunk, single dorsal trunk, lateral vessels in v-ix, latero-esophageal hearts in x-xi.

Fan-shaped ovaries, with funnels free in xiii; paired large spermathecae in viii, consisting of long narrow duct ectal 2/3 of which muscular, duct nearly as long as segment viii, sharply demarcated ampulla bent in irregular Sshaped curve ( Fig. 11b ).

Male sexual system proandric, testes and funnels free in x, vas deferens superficial on body wall from 10/11 to xviii where it enters bright white glandular mass; seminal vesicles in ix large acinous, laterally placed on body wall, large and post-septal in xi; slender tubular prostates folded under intestine within xvii-xxxvi, xxxix; prostatic ducts slightly muscular, no copulatory bursa domes.

Remarks. There are five previously-known species in the nominate subgenus, B. (B.) jimi Righi, 1984 , B. (B.) pocaju Righi, 1984, B. (B.) arua Righi, 1984, B. (B.) otarion Righi, 1995, and B. (B.) vaucheri Zicsi, 1995. The new species described here and B. (B.) otarion are distinguished from the others by having spermathecal pores in 7/8, spermathecae in viii, and seminal vesicles in ix and xi. However, the new species differs from that species and all others in the subgenus by having prostatic pore papillae elevated with seminal grooves on the posterior faces of the papillae, nephridia commencing in xii or xiii; prostates extending posteriorly past xxx, and sessile glands associated with the entry of the vas deferens into the body wall in segment xviii. The male pores are in mid- xviii rather than at 17/18 as in B. (B.) otarion, the clitellum of B. (B.) riparius sp. nov. is annular, and it has genital markings in the male field. The following DNA barcodes are from type series specimens: GU013848, GU013849.

Figures

FIGURE 11. Belladrilus riparius sp. nov. A. Composite ventral view, details of spermathecal pore (SP) and male field segments; B. Internal view spermatheca (S); C. Cross section of calciferous gland, scale bars 1 mm.