Amynthas chungchi Shen, 2025

Amynthas chungchi Shen sp. nov.

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Fig. 1 View Fig

Amynthas corticis View in CoL – James et al. 2005: 1023 (partim).

Diagnosis

Length (clitellates) 72–116 mm. Segments numbering 95–113. Setae 33–42 in VII, 43–52 in XX, 10–13 between male pores. First dorsal pore in 11/12. Clitellum XIV–XVI. Spermathecal pores four pairs in 5/6–8/9, 0.30–0.31 body circumference ventrally apart. Male pores 0.23–0.30 body circumference ventrally apart in XVIII, each with an anteromedial and a posteromedial genital papilla. Genital papillae widely paired in presetal VIII–IX or VII–IX. Additional papillae often widely paired in postsetal VIII and occasionally present in postsetal VII. Spermathecae four pairs in VI–IX. Seminal vesicles large, two pairs in XI and XII. Prostate glands large, occupying four to six segments in XV–XX. Prostatic ducts long, U-shaped in XV–XVIII or XVI–XVIII. Accessory glands sessile in preclitellar region and absent in postclitellar region.

Etymology

The species is named after Dr. Chung-Chi Hwang who helped extensively with the collection work, as mentioned in James et al. (2005).

Type material

Holotype

TAIWAN • clitellate (mature) specimen; Nanrenshan, Kending , Pingtung County; 22°05′03″ N, 120°50′07″ E; 150 m a.s.l.; 13 Jul. 1998; Chung-Chi Hwang leg.; NMNS-8595-001. GoogleMaps

Paratypes

TAIWAN • 6 clitellates; same data as for holotype; NMNS 4054-003 View Materials GoogleMaps .

Other material examined

TAIWAN • 1 clitellate; Nanrenshan, Kending , Pingtung County; 22°05′03″ N, 120°50′07″ E; 150 m a.s.l.; 20 Oct. 1996; Chung-Chi Hwang leg.; NMNS-8595-004 (this specimen was separated out from the others stored in the bottle labeled with catalogue no. NMNS 4054-031 View Materials ) GoogleMaps .

Description

Length (mature) 72–116 mm. Number of segments 95–113. Setae regularly distributed around segmental equators, size and distance regular, numbering 33–42 in VII, 43–52 in XX, 11–16 between spermathecal pores, 10–13 between male pores in XVIII. Prostomium epilobous. First dorsal pore in 11/12. Clitellum XIV–XVI, smooth, setae and dorsal pores absent, length 2.4–2.9 mm and width 2.5–3.7 mm. Spermathecal pores four pairs in 5/6–8/9 ( Fig. 1A View Fig ), paired pores 0.30–0.31 body circumference ventrally apart. Genital papillae widely paired in presetal VII–IX for four specimens, widely paired in presetal VIII–IX for four specimens, widely paired in postsetal VIII for four specimens, one on left side of postsetal VII for one specimen, and one on right side of postsetal VII for one specimen, each papilla 0.25–0.4 mm in diameter. Female pore single, mid-ventral in XIV.

Male pores paired, ventro-lateral in XVIII, paired pores 0.23–0.30 body circumference ventrally apart. Two small papillae medial to each male pore in XVIII, one anteromedial and the other posteromedial, surrounded by three or four circular folds ( Fig. 1B View Fig ). Each papilla 0.13–0.3 mm in diameter. Preserved specimens brown on dorsum, light greyish brown on venter, dark brown on clitellum.

Septa 5/6–7/8 thickened, 8/9/10 absent, 10/11–13/14 thickened. Nephridial tufts on anterior faces of 5/6/7. Gizzard in VIII–X. Intestine enlarged from XV. Intestinal caeca paired in XXVII, simple, long, surface slightly wrinkled, extending anteriorly to XXIII or XXII. Esophageal hearts paired in XI–XIII.

Spermathecae four pairs in VI–IX. Ampulla large, round, peach- or elongated oval-shaped, surface wrinkled, 1.1–1.8 mm in length and 0.7–1.8 mm in width, with a short, stout stalk 0.3–0.5 mm long. Diverticulum with an oval, iridescent seminal chamber 0.3–0.5 mm in length and a slender stalk 0.4–1.0 mm in length ( Fig. 1C View Fig ). Accessory glands sessile, round, 0.3–0.4 mm in total length, each corresponding to external genital papilla. Ovaries paired in XIII.

Holandric. Testes oval, two pairs in ventrally joined sacs in X and XI. Seminal vesicles large, two pairs in XI and XII, each vesicle occupying 1–2 segments, with a round, prominent dorsal lobe. Prostate glands paired in XVI–XX, XV–XX or XVI–XIX, wrinkled and lobed. Prostatic ducts large, long, U-shaped in XV–XVIII or XVI–XVIII, enlarged in distal half ( Fig. 1D View Fig ). Accessory glands absent.

Distribution

Known only from type locality (Nanrenshan, Kending, Pingtung County, Taiwan).

Remarks

The description of “ A. corticis ” by James et al. (2005: 1023–1024) was based on the seven specimens in the bottle labeled with catalogue no. NMNS 4054-003 only. The genital papilla arrangements in the preclitellar and male pore regions of the other specimens assigned to “ A. corticis ” by James et al. (2005: 1023), namely NMNS 4054-031, NMNS 4054-032, NMNS 4054-033, and NMNS 4054-034, are completely different from this description. James et al. (2005: 1024) mentioned in the “Remarks” section that “The material is very probably A. corticis ”. Obviously, James et al. (2005) were not fully sure about the identity of these specimens. Amynthas chungchi sp. nov. is most similar to A. corticis in the external characters. However, the character of two small papillae with one anteromedial and the other posteromedial to each male pore is consistent among the A. chungchi sp. nov. individuals and different from the variable papilla arrangements in the male pore region of A. corticis with the number of papillae ranging from zero to two, occasionally three, and the position being posterior, posteromedial, posterolateral, anterolateral and/or anteromedial to each male pore ( Chen 1931, 1933; HPS, personal observation). HPS has examined more than 1350 specimens of A. corticis , most of which with their identity confirmed by DNA barcode, collected throughout Taiwan and its adjacent islands. In conclusion, A. corticis has no postsetal papillae on the ventral side of the preclitellar region except those anterior to each spermathecal pore. This feature agrees with that of Pheretima heterochaeta (Michaelsen, 1891) (= A. corticis ) described by Chen (1931, 1933) and of A. corticis described and figured by Blakemore (2013a, 2013b, 2013c). Besides, the prostate glands of A. corticis are often absent, and its prostatic duct is always confined to segment XVIII no matter whether the duct is smaller and curved in a “C” shape, or larger and curved in a “U” shape. In contrast, most individuals of A. chungchi sp. nov. have postsetal papillae and all of them have large prostate glands occupying four to six segments in XV–XX with large, long, U-shaped prostatic ducts extending in XV–XVIII or XVI–XVIII.

Amynthas chungchi sp. nov. also resembles Amynthas yizhou Blakemore, 2013 from northern Taiwan. The latter species was initially misidentified as a new record of A. carnosus by Shen et al. (2005), and was later named by Blakemore (2013c). Both species are octothecal and have one presetal and one postsetal papilla medial to each male pore. However, A. yizhou is larger, with a body length of 130–240 mm and a width of 5.99–8.25 mm, and it has higher setal numbers (42–51 in VII and 54–73 in XX), two or three small papillae ventral to each spermathecal pore near the intersegmental furrow, a diverticulum with an elongated seminal chamber, and a sessile accessory gland associated with each papilla around the male pore ( Shen et al. 2005).