Andiorrhinus meansi, James, Samuel W., 2009

James, Samuel W., 2009, Andiorrhinus meansi sp. n., a new giant earthworm from the Wokomung Massif, Guyana (Clitellata: Glossoscolecidae), Zootaxa 2116, pp. 53-58 : 54-55

Andiorrhinus meansi sp. n.

(Fig. 1A, B: ventral view, calciferous gland schematic)

Holotype. KUNHM 0 0 3008 adult. Type locality. Wokomung Massif, Guyana, Middle Camp, 05° 06.61' N, 59° 49.24' W, elevation 1135 masl. 16–18 July 2003, D.B. Means, coll.

Paratypes. KUNHM 0 0 3009, one subadult, one decapitated clitellate; same location as holotype, 30 July and 16 July 2003 respectively, D.B. Means, coll; KUNHM 0 0 3010, one adult Wokomung Massif, Guyana, Falls Camp, 05° 05.42' N, 59° 50.29' W, elevation 1364 masl. 27 July 2003, D.B. Means, coll.

Etymology. The species is named for D. Bruce Means, the collector.

Description. Dimensions 330–485 mm by 23–25 mm at x, 21–28 mm at clitellum, 20–24 mm at xxx, anterior two-thirds of body cylindrical, dorso-laterally flattened oval in posteriormost 60 segments, 201–234 segments. Setae ab commence on iii, cd on ix. Setae closely paired throughout; setal formula AA:AB:BC:CD = 22:2:27:1 at xxx. Prostomium withdrawn into buccal cavity, post-setal secondary annulations present iii–xv. Color in life a dark greenish turquoise dorsally, tan ventrally. The dorsal CMYK color values were: 63, 32, 53, 1, respectively. Body wall pigment in circular muscle layer, CMYK values from cross section of preserved specimen: 66, 14, 69, 0. Seguy(1936) color codes green #434 dorsally, red-brown #112 or #132 ventrally. Ovipores not seen; male pores not seen but probably near tubercula pubertatis in xviii (see internal characters); spermathecal pores paired in 6/7/8/9, about 2.5 mm below nephropores in BC; clitellum saddle to just above B, xvi–xxvi; tubercula pubertatis a narrow edge of the clitellum, xviii–xxii; genital markings tumid areas surrounding setae ab in xvii–xxii (Fig. 1A). Nephropores near D, with muscular cylindrical sphincter deeply embedded in body wall. Genital setae found in segments xvii–xxii, 3000–3200 μm long, 90–100 μm diameter, short taper to pointed tip, shafts ornamented with closely spaced crescentic indentations on distal third, entire circumference of shaft so ornamented.

Septa 5/6 thin, 6/7–16/17 thick, muscular, remaining septa membranous, except ventral portions of 17/ 18–22/23 which have muscle bands. Septal insertions on body wall slightly posterior to external segmental furrows, septa adherent to body wall about half of segment length in head segments. Trans-septal muscles lacking except 2 pairs very close to mid-ventral. Alimentary canal with large S-curve folded crop in v–vi, large ovoid gizzard in vi; esophagous lacking lamellar folds, valvular in xix–xx, intestinal origin xx or xxi; typhlosole origin xxix, end cxli, cxlvi (3), typhlosole simple blade much greater depth than intestinal diameter, folded three times in anterior intestine, terminates abruptly. Pyriform calciferous glands paired vii–ix, parallel lamellar internal structure with 30–32 lamellae per gland. Calciferous glands’ free ends directed ventrally, filling most of segments vii–ix, small ventral terminal knob present. Gland ducts attached to lateral pouches on sides of esophagus in each glandular segment, attachment between mid-dorsal and midlateral. Pouches deepest in vii, decreasing posteriorly. Usually a narrow extension of gland duct passes through esophageal wall into esophageal lumen (Fig 1B). Blood vessels to calciferous glands include large branch of supra-esophageal vessel along gland duct; each calciferous gland blood vessel passes from supraesophageal vessel immediately anterior to septum along dorsal edge of lateral pouch of esophagus before joining gland. Holonephric, vesiculate; ducts to body wall near level of D, nephropores pass through muscular cylinders which may be sphincters. Nephrostomes not seen.

Vascular system with ventral trunk, single dorsal trunk bifurcating on gizzard in vi, lateral vessels in vii–ix, esophageal hearts in x–xi. Supra-esophageal vessel 7/8-xvii.

Ovaries, ovarian funnels not found; spermathecae paired vii–ix, each a simple ampulla, basal third of wall with many small sperm chambers, ducts meet body wall posterior to septal insertions, ventral to nephridial ducts. Male sexual system holandric; testes, funnels, hearts and nephridia of segments x, xi, seminal vesicles of xi enclosed in annular sacs formed from membrane connecting septa either side of testicular segment; seminal vesicles simple smooth reniform attached post-septally in xi, xii, the former usually larger; vasa deferentia from testicular funnels, piercing septa close to ventral vessel, descending to body wall in xvii, then bending laterally and entering body wall above level of B in xvii.

FIGURE 1. Andiorrhinus meansi sp. n. A. Ventral view of anterior of holotype from Wokomung Massif, Guyana. B. Schematic cross-section diagram of calciferous gland (cg) attachment to esophagus, with duct extension (de) and blood vessel (bv) from supra-esophageal vessel (sev).

Remarks. In one specimen the vasa deferentia descended to the body wall directly from the funnels, entering the longitudinal muscle layer in xi and xii, where tracing was extremely difficult. In the decapitated specimen, some apparent tubules running parallel to the ventral nerve cord were traced within the body wall until lost somewhere in the neighborhood of xx. Not knowing the origin of these tubules it is hard to say what they are, because the location and arrangement is different from what are clearly vasa deferentia in other specimens. The difficulty finding nephrostomes indicates that nephrostomes are probably single rather than multiple per nephridium as in some large Martiodrilus species ( James 1990).