Amynthas fucatus Zhao and Jiang, 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 : 2185-2187

Amynthas fucatus Zhao and Jiang , sp. nov.

( Figure 3 )

Type material

Holotype: Clitellate specimen (C-HN201114-01Z): 137 mm long, 4 mm wide. Setae numbers: 44/III, 52/ V, 60/ VIII, 40/XX, 48/XXV; 26( V), 24( VI), 26( VII), 30( VIII) between spermathecal pores, 8( XVIII) between male pores; collected in tropical rain forest of Quling Mountain in Limushan Nature Reserve, 19 ◦ 13 ′ 40 ′′ N, 109 ◦ 44 ′ 15 ′′ E, at an altitude of 739 m. Collected by J. P. Qiu, Q. Zhao, J. B. Jiang, D. Cluzeau and W. K. Zhang.

Other material

Some data as for holotype, one aclitellate specimen.

Etymology

The species is named for its pigmentation anterior to the clitellum.

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 about 0.4 body circumference apart, ventrally placed, each on top of a conical porophore, two ovoid genital papillae in the inner side of male pore, and all of them are surrounded by three to five skin folds. Another small pair of round papillae positioned in the middle of XVIII ventrally above setae line.

Description

Preserved specimens dark red brown dorsally and light red brown ventrally before clitellum, pale after clitellum both dorsally and ventrally. Dimensions 137 mm by 4 mm. Setae intensive, regularly distributed around segmental equators, their numbers: 44/III, 52/V, 60/VIII, 40/XX, 48/XXV; 26(V), 24(VI), 26(VII), 30(VIII) between spermathecal pores, 8(XVIII) between male pores; setal formula AA = 1–2.5AB, ZZ = ZY. Female pore single in the ventral centre of XIV, ovoid, brown. First dorsal pore in 11/12. Prostomium epilobous. Clitellum in XIV–XVI, ring-shaped, red-brown, markedly glandular; ventral setae invisible, but dorsal pore visible.

Male pores paired in XVIII about 0.4 body circumference apart, ventrally placed, each on top of a conical porophore, two ovoid papillae in the inner side of male pore, both male pore and papillae are surrounded by three to five skin folds. Another small pair of round papillae positioned in the middle of XVIII ventrally above setae line. Spermathecal pores two pairs in 5/6–6/7, ventral, 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; 10/11–11/12 thin. Gizzard ball-shaped, in IX–X. Intestine starting enlarged in XIV. Intestinal caeca simple, originating in XXIII, extending anterior to XXVI, dark brown, smooth ventrally and dorsally. Oesophageal hearts four pairs, in X–XIII.

Spermathecae two pairs, in VI–VII; ampulla elongated ovoid, duct about 0.5 of ampulla, distinctly separated; diverticulum about 0.33 of main pouch and straight, ental 0.75 enlarged, serving as virgulate seminal chamber which is whitish in appearance. Testis-sacs paired in X and XI. Seminal vesicles paired in XI and XII. Prostate gland in XV–XXI, developed, coarsely lobated, with a stout U-shaped duct.

Remarks

Amynthas fucatus sp. nov. also keys to morrisi -group according to Sims and Easton (1972). In appearance, Amynthas fucatus sp. nov. is somewhat similar to Amynthas incongruus ( Chen, 1933) . They are moderate-sized species with pigmentation, the first dorsal pore in 11/12, two pairs of spermathecal pores in 5/6–6/7, a developed prostate and simple intestinal caeca. Genital papillae occur around the male pores and a small pair of papillae is placed medioventrally in XVIII in both species. However, only Amynthas fucatus sp. nov. has two ovoid papillae on the inner side of each male pore and no genital markings. Although the diverticulum is small in both species, it has no distinct seminal chamber in Amynthas fucatus sp. nov. Furthermore, there is no accessory gland in Amynthas fucatus sp. nov. ( Table 3). In addition, Amynthas fucatus sp. nov. is also similar to Amynthas lubricatus ( Chen, 1936) to some extent. They are moderate-sized species, their first dorsal pore is in 11/12, and they have two pairs of spermathecal pores in 5/6–6/7, simple intestinal caeca, an indistinct seminal chamber and neither accessory glands nor genital markings. However, they are clearly different from each other in the male pore region, pigmentation, prostate and diverticulum. Amynthas fucatus sp. nov. has pigmentation and genital papillae. Its prostate is developed but diverticulum is small ( Table 3). The distance between COI sequences of Amynthas fucatus sp. nov. and the other four Amynthas species is always>18%. Furthermore, the distances between combined COI and 16S sequences are also>15% ( Figure 5 , Table 2). Sequences of COI and 16S genes of Amynthas fucatus were deposited in GenBank under Accession No. KF151185 and JQ911675 ( Table 1).

Figures

Figure 3. Amynthas fucatus 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.