Amynthas endophilus Zhao and Qiu, 2013

Zhao, Qi, Sun, Jing, Jiang, Jibao & Qiu, Jiangping, 2013, Four new species of genus Amynthas (Oligochaeta, Megascolecidae) from Hainan Island, China, Journal of Natural History (J. Nat. Hist.) 47 (33 - 34), pp. 2175-2192 : 2176-2183

Amynthas endophilus Zhao and Qiu , sp. nov.

( Figure 1 )

Type material

Holotype: Clitellate specimen (C-HN201011-03): 96 mm long, 3 mm wide, 159 segments. Setae numbers: 56/III, 72/ V, 84/ VIII; 25( VI) between spermathecal pores, 2( XVIII) between male pores; collected in the black loam near the river which is behind the hotel in Diaoluoshan National Forest Park , south-east Hainan, 18 ◦ 43 ′ 49 ′′ N, 109 ◦ 52 ′ 03 ′′ E, at an altitude of 933 m. Collected by J. P. Qiu, Q. Zhao, J. B. Jiang, D. Cluzeau and W. K. Zhang . Paratype: 1 clitellate (C-HN201011-03(1)): same data as for holotype.

Other material

Some data as for holotype, 1 aclitellate specimen.

Etymology

The species is named after its ecological type. It was collected from deep soil and is without pigmentation. It is an endogeic species.

Diagnosis

Spermathecal pores two pairs, ventral, in 5/6–6/7, about 0.4 body circumference apart. No genital markings in this region. Male pores a little less than 0.33 body circumference apart, ventrally placed, each on top of a round glandular porophore, surrounded by four skin folds. No genital papillae in this region.

Description

Preserved specimens no pigmentation. Dimensions 96 mm by 3 mm; segments 159. Setae intensive, regularly distributed around segmental equators, their numbers: 56 at III, 72 at V, 84 at VIII; 25(VI) between spermathecal pores, 2(XVIII) between male pores; setal formula AA = 1.4AB, ZZ = 2ZY. Female pore single in the centre of XIV ventrally, ovoid, brown. First dorsal pore in 12/13. Prostomium 1/2 epilobous. Clitellum in XIV–XVI, ring-shaped, light greyish, markedly glandular; setae, dorsal pore and annulus invisible.

Male pores paired in XVIII, a little less than 0.33 body circumference apart, ventrally placed, each on top of a round glandular porophore, surrounded by four skin folds. Genital papillae absent. Spermathecal pores two pairs, ventral, in 5/6–6/7, each eye-shaped and obvious, distance between paired pores about 0.4 body circumference apart. Genital markings absent.

Septa 8/9, 9/10 absent; 5/6–7/8 comparatively thick and muscular; 10/11–12/13 a little thicker than those following. Gizzard ball-shaped, in IX–X. Intestine starting enlarged in XV. Intestinal caeca simple, originating in XXVII, extending anterior to XXIV, dark brown. Oesophageal hearts four pairs, in X–XIII, the last three more developed.

Spermathecae two pairs, in VI–VII, 2.3 mm long; ampulla elongated ovoid, duct a little shorter than ampulla, diverticulum 1.8 mm long, ental 0.6 dilated, serving as zonal seminal chamber, silvery white. Testis-sacs paired in X and XI, both separate ventrally. Seminal vesicles paired in XI and XII, stout and developed, both separate ventrally. Prostate gland in XVII–XXI, developed, racemose, and divided into five to six main lobes, with a 6- or U-shaped duct, uniform in calibre.

Remarks

Amynthas endophilus sp. nov. keys to the morrisi- group according to Sims and Easton (1972). Compared to the Amynthas species reported from China and South-East Asia with two pairs of spermathecal pores in 5/6–6/7 ( Chen 1931, 1933, 1936, 1938, 1946; Gates 1935, 1939a, 1939b; Chen et al. 1975; Chen and Hsu 1977; Ding 1985, Tsai 1964; 1972; Qiu and Wen 1987; Hong and James 2001, 2004, 2008; James et al. 2005; Hong 2007, 2011), Amynthas endophilus sp. nov. is most similar to Amynthas morrisi (Beddard, 1892) . Both of them are moderate-sized species. Their spermathecae are similar: both of them have an ovoid ampulla and a slender duct which is a little shorter than the ampulla; the diverticulum is shorter than the main pouch with a zonal seminal chamber. Furthermore, both of them have two pairs of spermathecal pores in 5/6–6/7, no septa in 8/9–9/10, racemose prostate gland and simple intestinal caeca. However, they differ by the pigmentation, genital markings, genital papillae, first dorsal pore and gizzard. Amynthas endophilus sp. nov. has no pigmentation while Amynthas morrisi is brownish dorsally and grey ventrally. Amynthas endophilus sp. nov. has neither genital markings nor genital papillae. In contrast, genital markings are sometimes present in Amynthas morrisi and Amynthas morrisi always has genital papillae pre- and post-male pores. The first dorsal pore of Amynthas endophilus sp. nov. is in 12/13 while that of Amynthas morrisi is in 11/12. The gizzard of Amynthas endophilus sp. nov. is in IX–X, while that of Amynthas morrisi is in IX or VIII–IX ( Table 3). An NJ tree and K2P distances among Amynthas species ( morrisi -group) in China mainland, Taiwan Island and Hainan Island are shown in Figure 5 and in Table 2. The distance between COI markings if present, small, if present, paired

posterior to each number and in VI and/or VII,

pore, except for position variable, pre- and/or

three tiny papilla in V–VII, post-setal,

markings VI–VII, or VII slightly medial to

posterior to the only, mid-ventral spermathecal

left pore in 6/7 or just medial to pores

spermathecal

pores Gizzard IX–X IX–X IX–X IX or VIII–IX IX–X IX–X Septa in 8/9/10 Absent Absent Absent Absent Absent 8/9 thick and

tenacious,

9/10 less

thickened Spermathecae Ampulla elongated Ampulla ovoid, Ampulla elongated Ampulla oval or Ampulla Ampulla round or

heart-shape, duct duct slender, heart shape, duct pear-shaped, elongated, oval, sub-spherical,

a little shorter about 0.25 of about 0.5 of stalk slender, stalk slender, duct stout, about

than ampulla, ampulla, ampulla, straight, approximately 0.5 of ampulla,

diverticula diverticula short, diverticula about diverticulum equal to the diverticulum

1.8 mm long, as long as 0.25 of 0.33 of main slender with a length of elongate,

ental 0.6 dilated, main pouch, pouch and thin stalk and a ampulla, club-shaped,

serving as zonal ental straight, ental dilated, diverticulum equal or slightly

seminal chamber 0.25 swollen, 0.75 enlarged as elongated bulb absent or small, shorter than

serving as virgulate seminal with a round main pouch with

seminal chamber chamber seminal chamber a short and

slender duct,

ental

0.67 straight and

slightly enlarged

(Continued)

sequences of Amynthas endophilus sp. nov. and the other four Amynthas species are all more than 20%. Furthermore, the distances of the combined COI and 16S sequences were>13%. Sequences of COI and 16S genes of Amynthas endophilus were deposited in GenBank under Accession No. JQ911673 and JQ911674 ( Table 1).

Figures

Figure 1. Amynthas endophilus sp. nov. (A) ventral body surface with spermathecal pores; (B) spermatheca; (C) ventral body surface with male pores; (D) Intestinal caeca.

Figure 5. Neighbour joining (NJ) tree of Amynthas species; (A) based on COI sequences; (B) based on combined COI and 16S genes.