Amynthas somechanae, Hong & Inkhavilay & James, 2018

Hong, Yong, Inkhavilay, Khamla & James, Samuel W., 2018, Nine new species of the " aeruginosus " - group in Amynthas (Clitellata: Megascolecidae) from Nam Et-Phouley National protected Area, Laos, Zootaxa 4496 (1), pp. 238-250 : 244

Amynthas somechanae sp. nov.

( Figure 2C,D )

Material. Holotype: clitellate ( BDNUL0041 ): Laos, Hoaphane Province , Nam Et-Phouley NPA, Viengthong district, Thad Ang waterfall area, 792 m (20o 15. 446' N, 103o 08– 921' E), good condition mossy forest with big trees, dark soil and thick litter layer, 21 July 2005, Phimphet, Xay, Ammaline, Phoang sone, and K. Inkhavilay colls . Paratypes: 2 clitellates ( BDNUL0042 , BDNUL0043 ), same data as for holotype . Other material: 5 clitellates, same data as for holotype .

Etymology. Named for Dr. Somechan Bounphanmy, Dean of Faculty, Laos National University who gave much support to the Laos earthworm survey.

Diagnosis. Spermathecal pores two pairs in 7/8–8/9 at 11th setal lines; male pores in XVIII at 10th setal lines within paired approximately circular thickened areas containing equatorial circular genital papillae; 0.20–0.33 circumference apart ventrally, indistinct paired epidermal thickenings equatorial in XVII, XIX in line with reniform papillae, first dorsal pore 5/6, typhlosole vestigial, prostatic ducts coiled clockwise L and anti-clockwise R.

Description. Dimensions 82–120 mm, by 4.5–5.0 mm at segment X, 4.5–5.0 mm at segment XXX, 4.9–5.4 mm at clitellum; body ventrally flattened, segments 47–105. Ventral surface across GG (from XXV) narrowing to EE (XXXV and after) elevated except intersegmental furrows, ladder-like appearance. Setae regularly distributed around segmental equators, numbering 52–56 at VII, 43–58 at XX, 8–10 between male pores, ventral setae VIII, IX often absent; setal formula AA:AB:ZZ:YZ= 5:2:4:2.5 at XIII. Female pore single at XIV on an oval porophore 0.5–0.6 mm in diameter. Prostomium epilobic with tongue open, dark purple brown dorsally, ventral pigment only in I–IV, clitellum dark brown, formalin preservation. First dorsal pore at 5/6, clitellum annular XIV–XVI; setae invisible externally. Male pores in XVIII at 10th setal line within paired approximately circular thickened areas containing equatorial circular genital papillae, laterally adjacent reniform or bean seed-shaped papillae on whose convex lateral edges are male pores, pores 0.20–0.33 circumference apart ventrally. Indistinct paired epidermal thickenings equatorial in XVII, XIX in line with reniform papillae. Spermathecal pores paired in 7/8, 8/9 at 11th setal lines within thickened lips, at lateral margin of ventrum, 0.29–0.35 circumference apart ventrally.

Septa 5/6, 6/7 thick, 7/8 thin, 8/9/10 absent, 10/11–13/14 thin. Gizzard globular in VIII–X. Intestine enlarged from XV, lymph glands not found. Typhlosole vestigial from XXVII. Intestinal caeca simple originating in XXVII and extending anteriorly about to XXV, finger-shape sac. Hearts esophageal X–XIII; X smaller than other pairs. Male sexual system holandric, testes and funnels in ventrally joined sacs in X, XI. Seminal vesicles paired without dorsal lobes in XI, XII. Prostates in XVIII, extending from XVII–XX, glands consisted of 12–13 small lobes; long muscular duct spirals clockwise L, anti clockwise R. Many small cysts on intestine and body wall. Ovaries in XIII. Spermathecae two pairs in VIII, IX; ampulla large pouch, flattened by gizzard, bent 90 0 from axis; base, side bound to duct, irregularly shaped, posterior pair bigger, diverticulum with irregular spherical chamber colored by small black spots; slender stalk attached to base of spermathecal duct, no nephridia on ducts.

Remarks. This species in the Laotian aeruginosus -group section, characterized by long prostatic ducts often in mirror-image coils, first dorsal pores in 5/6 or nearby, and lack of pre-clitellar genital markings. Among the species reported here, in Hong (2010) and by Thai and Samphon (1989), A. somechanae sp. nov. is distinguished by the vestigial typhlosole and reniform genital papillae adjacent to the male pores. It is closest in general appearance to A. bouatongi sp. nov., but lacks that species' circular genital papillae lateral to the male pores and is larger and of a different color.

Figures

FIGURE 2. Amynthas nametensis sp. nov. (A,B), Amynthas somechanae sp. nov. (C,D), and Amynthas wiggeri sp. nov. (E,F). A,C,E: ventral view; B,D,F: spermatheca. Scale bars 2 mm.