Amynthas douliouensis

Shen, Huei-Ping, Chang, Chih-Han & Chih, Wen-Jay, 2016, Four new earthworm species of the genus Amynthas (Megascolecidae: Oligochaeta) from southwestern Taiwan with re-description of Amynthas tungpuensis Tsai, Shen and Tsai, 1999, Journal of Natural History 50 (29 - 30), pp. 1889-1910 : 7-10

publication ID	https://doi.org/ 10.1080/00222933.2016.1180721
DOI	https://doi.org/10.5281/zenodo.5195223
persistent identifier	https://treatment.plazi.org/id/0E1A9660-B33B-3462-FEC0-FD3EFE7FFC89
treatment provided by	Plazi
scientific name	Amynthas douliouensis
status

Treatment

Amynthas douliouensis Shen and Chang, sp. nov.

( Figure 3 View Figure 3 )

Type material

Holotype. Clitellate (mature) specimen (78 mm in length, dissected) collected 11 December 2007 from roadside slope along the Fongshuhu South Creek (elevation 150 – 210 m) near the borders of Douliou and Linnei, Yunlin by C.H. Chang, T.J. Lin and Y.P. Li (TESRI-O-H-48) (voucher number: WH3P12).

Paratype. One clitellate (same collection data as holotype, TESRI-O-P-43).

Other material

Six clitellates (voucher number of specimen used for DNA barcoding analyses: WH3P3) and an aclitellate collected 12 June 2007 from roadside slope along Waihu Creek (elevation 230 m) near the borders of Douliou and Linnei, Yunlin by M.H. Chen (coll. no. 2007 – 24); two clitellates collected 27 June 2007 from type locality by S.T. Chang and Y.P. Li (coll. no. 2007 – 27); five clitellates (voucher number of specimen used for DNA barcoding analyses: WH3P14) and an aclitellate collected 18 July 2007 from type locality by C.H. Chang, T.J. Lin and Y.H. Lin (coll. no. 2007 – 45); two clitellates collected 16 August 2007 from type locality by C.H. Chang, Y.H. Lin and Y.P. Li (coll. no. 2007 – 65; voucher number of specimen used for DNA barcoding analyses: WH3P13); one clitellate collected 13 September 2007 from type locality by T.J. Lin, Y.P. Li, L.H. Chen and H.I. Tsai (coll. no. 2007 – 85) (voucher number: WH3P11); one clitellate collected 30 October 2007 from type locality by C.H. Chang, T.J. Lin and Y.P. Li (coll. no. 2007 – 105).

Diagnosis

Small to medium; length (clitellates) 78 – 120 mm. Segments numbering 82 – 99. Setae 40 – 45 in VII, 48 – 57 in XX, 9 – 14 between male pores. Clitellum XIV – XVI. First dorsal pore in 11/12 or 12/13. Spermathecal pores three pairs in 6/7 – 8/9, 0.29 body circumference ventrally apart. Male pores 0.25 body circumference ventrally apart in XVIII, each on a round porophore surrounded by three or four circular or diamond-shaped folds. Genital papillae widely paired in presetal VIII and IX, and absent, single or closely paired immediately anterior to setal line in the mid-ventral position in IX and X, number variable. Spermathecae three pairs in VII – IX. Accessory glands stalked, each corresponding to external genital papilla. Seminal vesicles small, two pairs in XI and XII. Prostate glands large in XVI – XX. Prostatic duct long, U-shaped in XVII – XVIII.

Description

External characters. Total length (clitellates) 78 – 120 mm. Weight 0.62 – 1.29 g. Segments numbering 82 – 99. Clitellum XIV – XVI, setae and dorsal pores absent, length 2.60 – 3.98 mm and width 3.16 – 4.55 mm. Prostomium epilobous. Setal number 40 – 45 in VII, 48 – 57 in XX, and 9 – 14 between male pores in XVIII. First dorsal pore in 11/12 or 12/ 13. Spermathecal pores three pairs in intersegmental furrows of 6/7 – 8/9, distance between paired pores about 0.29 body circumference ventrally apart ( Figure 3 View Figure 3 a). Genital papilla presetal, usually widely paired in presetal VIII and IX, and absent, single or closely paired immediately anterior to setal line in the mid-ventral position in IX and X, number variable. For 20 specimens examined, in VIII, two (widely paired) in 12 specimens, one on right in three specimens, absent in five specimens; in IX, four (widely and closely paired) in 11 specimens, three (widely paired and single median) in four specimens, two (widely paired) in four specimens, two (single median and one on left) in one specimen; in X, two (closely paired) in nine specimens, single median in three specimens, absent in eight specimens. Each papilla round, about 0.3 mm in diameter. Female pore single, mid-ventral in XIV.

Male pores simple, paired in XVIII, about 0.25 body circumference ventrally apart, each on a small, round porophore surrounded by three or four circular or diamondshaped folds ( Figure 3 View Figure 3 b). Genital papillae usually absent in the postclitellar region, one tiny papilla anteromedial to right male porophore in one specimen and two tiny papillae anteromedial to left male porophore in one specimen.

Preserved specimens reddish brown on dorsum and preclitellar region with orange brown clitellum and greyish brown ventrum.

Internal characters. Septa 5/6 – 7/8 thick, 8/9/10 absent, 10/11 membranous, 11/12 – 13/ 14 muscular. Nephridial tufts on anterior faces of 5/6/7. Gizzard large in VIII – X. Intestine enlarged from XVI. Intestinal caeca long, simple, paired in XXVII and extending anteriorly to XXI. Oesophageal hearts in XI – XIII.

Spermathecae three pairs in VII – IX, varied in size and shape ( Figure 3 View Figure 3 c). Each ampulla round, peach-shaped or elongated oval-shaped, surface wrinkled, 1.05 – 1.23 mm long and 0.65 – 0.97 mm wide, with a short, stout spermathecal stalk about 0.2 mm in length. Diverticulum with an iridescent, oval-shaped seminal chamber of 0.45 – 0.60 mm long and a slender stalk of 0.60 – 0.77 mm in length. Accessory glands stalked, 0.70 – 0.80 mm in total length, each corresponding to external genital papilla ( Figure 3 View Figure 3 c).

Holandry: testes oval, two pairs in ventrally joined sacs in X and XI. Seminal vesicles small or normal, two pairs in XI and XII, occupying one-third to nearly full segmental compartment. Pseudovesicle absent or present in XIII. Prostate glands in XVI – XX, large, smooth, lobed ( Figure 3 View Figure 3 d). Prostatic duct long, U-shaped in XVII – XVIII, stouter toward distal end. Accessory glands absent.

DNA barcodes

GenBank accession numbers KU232822 View Materials (WH3P12, holotype), KU232825 View Materials , KU232821 View Materials , KU232823 View Materials and KU232824 View Materials (WH3P3, 11, 13 and 14, respectively).

Etymology

The name douliouensis is given to this species with reference to its type locality in Douliou, Yunlin, southwestern Taiwan.

Remarks

Amynthas douliouensis sp. nov. is only known from its type locality and the type locality of A. quadriorbis in the foothills near Douliou, Yunlin, southwestern Taiwan. The two type localities are only 1 km away from each other in areas where natural habitats have mostly been transformed into farmlands, and so A. douliouensis may also be considered as an endangered species like A. quadriorbis .

Amynthas douliouensis is sexthecate with three pairs of spermathecae in VII – IX and belongs to the sieboldi species-group of the genus Amynthas ( Sims and Easton 1972) . It is most similar to A. tungpuensis , an endemic earthworm widely distributed in western Taiwan, based on the characters of setal numbers, simple male pore structure, stalked accessory glands and three pairs of spermathecae in VII – IX. The presence of stalked accessory glands in A. tungpuensis was neglected in the original description of Tsai et al. (1999). Despite these similarities, A. tungpuensis is morphologically separable from A. douliouensis because it has distinctive violet brown colouration with white setal rings and generally two transverse rows of papillae in presetal VIII and IX ( Tsai et al. 1999). Molecular analyses also show that A. douliouensis is distinguishable specifically from A. tungpuensis ( Figure 1 View Figure 1 ). Amynthas douliouensis differs from the other members of the sieboldi -group primarily by its combined characters of simple male pore and unique papilla arrangements.