Amynthas munglongoides Nguyen, Lam

Grzelak, Katarzyna & Sørensen, Martin V., 2022, Echinoderes blazeji Grzelak & amp; Sørensen 2022, sp. nov., Zoological Studies 55 (52), pp. 1-13 : 2-8

Amynthas munglongoides Nguyen, Lam &

Nguyen sp. nov. lsid:zoobank.org:act: F669ACC7-13D2-40FA-AB7A- FC01EE1918CA ( Fig. 4 , Table 1)

Material examined: Holotype: One mature ( CTU-EW037 -h01) Vietnam, Ha Giang province, Vi Xuyen District, Cao Bo commune, elevation of 1,492 m a.s.l., 22°47'33,9"N - 104°52'07,9"E; 07/2008, coll. Nguyen Hoang Ngoc.

Paratype: One mature ( CTU-EW 037-p01) together with holotype.

Diagnosis: Large-size worm, length ca. 252-318 mm, diameter ca. 15.5-16.0 mm. First dorsal pore in 11/12. Prostomium epilobous.

(A)

Spermathecal pores round and small, ventrally paired in intersegmental furrows 5/6/7/8. Male pores located in xviii, without copulatory pouches. Genital makings present on both spermathecal and male pore regions (on vii, viii, and xviii). Holandric.

(B)

Spermathecal ampulla egg-shaped, duct almost reduced. Testis sacs separated. Intestinal caeca manicate. Septa 8/9/10 absent.

Etymology: “ munglongoides ” is an adjective in apposition to emphasize its similarity to the species, A. munglonganus ( Thai & Tran, 1986)

Description: External characters: Body cylindrical, large size; length 252-318 mm, diameter 15.5-16.0 mm, weight 18.62-37.86 g; 98-116 segments. Body uniformly whitish grey. Prostomium 1/3 epilobous. First dorsal pore large, in 11/12. Setae perichaetine, short; pre-clitellar setae stouter and sparser than post-clitellar setae, 66-76 in v, 84-98 in viii, 94-99 in x, 91-94 in xx, 106 in xxv, 105-107 in xxx, 20-35 between male porophores in xviii; setal distance aa = 1.5- 2.0 ab, zz = 1.5-2.0 zy. Clitellum annular, xiv-xvi, darkish brown, smooth and without setae and dorsal pores. Female pore single, mid-ventral in xiv. Spermathecal pores round and small, ventrally paired in intersegmental furrows 5/6/7/8. Two pairs of round genital markings ventrally present in front of setal rings on vii and viii; ventral distance between genital markings about 0.25x body circumference. Male pores directly opened in xviii, without copulatory pouches; ventral distance between male porophores about 0.35x body circumference. Three pairs of genital markings present in xviii: one pair bean-shaped closing to male porophore; two pairs crescentic in front of and behind setal ring of xviii, the anterior pair larger than posterior one.

Internal characters: Septa 5/6/7/8 thickened, 8/9/10 absent, 10/11/12/13 thickened. Oesophageal gizzard within viii-x. Intestinal origin at xv; caeca manicate, originating at xxvii and extending anteriorly to xxiv or xxii. Last hearts in xiii. Pharyngeal micronephridia developed in 4/5/6. Lymph glands present from xvi. Typhlosole simple, lamelliform, poorly developed. Spemathecae paired ventrally, in vi-viii. Spermathecal ampulla large, egg-shaped, yellowish white; duct extremely short, almost absent. Diverticula very short, opalescent, directly attached to body wall, close to ampulla duct. Two pairs of accessory glands opalescent in vii and viii. Holandric. Testis sacs separated, in x and xi. Seminal vesicles well developed within xi-xii, and a pseudoseminal vesicle large in 13/14. Oviduct on septum 12/13 posteriorly; ovaries well developed in 12/13. Prostate glands deeply racemose, paired in xvi-xix; prostatic ducts U-shaped, slightly bigger distally. Accessory glands absent in male region.

Habitat: The new species was found in very high elevation, ca. 1,500 m a.s.l. It can be epigeic species because it was collected from soil surface.

Remarks: The new species can be classified into the hawayanus species group characterised by holandric and three pairs of spermathecal pores in intersegments 5/6/7/8 ( Sims and Easton 1972). It can be distinguished by its large size and pattern of genital markings on the spermathecal and male regions.

When compared with the large species found in Vietnam, the new species is similar to Amynthas dangi ( Thai, 1984) , Amynthas munglonganus Thai & Tran, 1986 ), and Amynthas ghilarovi ( Thai, 1982) by its large size, epilobous prostomium, septa 8/9/10 absent, intestinal caeca manicate, last hearts in xiii, and copulatory pouches absent ( Table 1). However, Amynthas dangi differs from the new species in having two pairs of spermathecal pores in 7/8/9, a genital marking closed to the male pore and an additional three pairs of genital markings on ventral xviii and xix. Amynthas munglonganus is distinguished from the new species by the first dorsal pore in 12/13, three pairs of small genital markings located closely to the spermathecal pores, a medium genital marking next to the male pore, and different shape of the spermathecal ampulla. The other large species, Amynthas ghilarovi ( Thai, 1982) , is slightly smaller than the new species, and has three pairs of spermathecal pores in 6/7/8/9, small, round genital markings located behind spermathecal pores, two pairs of sub-semicircular genital markings located in front of and behind the male pore, and presence of copulatory pouches. The other large species, A. mekongianus ( Cognetti, 1922) differs from the new species by having longer length (up to 2.900 mm) and smaller diameter (less than 10 mm), four pairs of spermathecal pores in 4/5/6/7/8 or 5/6/7/8/9, and no genital markings in both spermathecal and male regions.

In comparison to M. taiwanensis , the new species shares the large size (more than 16 mm in diameter). M. taiwanensis differs from the new species in first dorsal pore in 12/13 or 13/14, four pairs of spermathecal pores in 5/6/7/8/9, genital markings oval-shaped, located in front of porophores, male pores located inside copulatory pouches, and proandric. A character comparison among large pheretimoid species is presented in the Table 1.

Figures

Fig. 4. Amynthas munglongoides sp. nov., holotype. A: Male pore region, ventral view (mp = male pore; gm = gential markings); B, G: Spermathecae and accessory gland (amp = ampulla; dv = diverticula; ag = accessory gland); C, E: Intestinal caeca; D; Prostatic gland; F; Male pore region, ventral view; H: Spermathecal region, ventral view (sp = spermathecal pore). Scale bar = 1 mm.