Amynthas phucheefah Bantaowong & Panha, 2014

Bantaowong, Ueangfa, Somniyam, Pattana, Sutcharit, Chirasak, James, Samuel W & Panha, Somsak, 2014, Four new species of the earthworm genus Amynthas Kinberg, 1867, with redescription of the type species (Clitellata: Megascolecidae), Raffles Bulletin of Zoology 62, pp. 655-670 : 662-665

Amynthas phucheefah Bantaowong & Panha , new species

( Fig. 7 ; Table 2)

Material examined. Holotype: One adult ( CUMZ 3306 ), Phu Chee Fah, Thoeng, Chiang Rai, Thailand, (19°48ʹ47.0ʺN, 100°26ʹ20.4ʺE), 1205 m elevation, coll. S. Panha, U. Bantaowong, C. Sutcharit, P. Tongkerd, R. Chanabun, P. Pimvichai and P. Prasankok, 24 October 2008. Two paratypes ( CUMZ 3307 ) same collection data as for holotype.

Diagnosis. Large; length 215–314 mm. Male pores paired, superficial in segment XVIII. Small circular genital markings widely paired on 19/20–24/25. Spermathecal pores paired in segments 5/6–8/9, spermathecae large sac–shaped ampulla with nephridia on the duct, diverticulum long, loosely coiled, intestinal origin at XV, intestinal caeca simple, first dorsal pore in 12/13. Holandric. Prostate glands large, small sessile genital marking glands corresponding to external genital markings.

Description of holotype. Dimensions; 314 mm by 8.7 mm at segment VII, 8.2 mm at segment XX, 8.0 mm at clitellum; body cylindrical with 132 segments. Setae regularly distributed around segmental equators, numbering 71 at VII, 68 at XX, 19 between male pores, setal formula AA:AB:ZZ:ZY=1:1:1:1 at XIII. Single female pore at XIV. Prostomium epilobic. First dorsal pore at 12/13. Clitellum annular XIV–XVI with no setae.

Male pores paired, located ventro-laterally in XVIII, 0.31 circumference apart ventrally, distance between male pores 6.5 mm. Male pores superficial on XVIII, each pore situated on a top of small and elongated oval papilla surrounded by 3–4 circular ridges. Genital markings widely paired on 19/20– 24/25, in line with male pores, each one slightly elevated with a thick circular margin, and depressed in center. Single genital marking present on the left side of 25/26. Spermathecal pores four pairs, transverse slits, in furrows 5/6–8/9, ventral, distance between pairs about 0.3 body circumference ventrally apart, distance between spermathecal pores 10 mm. No genital markings on the spermathecal pores region.

Septa 5/6–7/8 thick, 8/9–9/10 absent, 10/11–11/12 thin. Gizzard large behind 7/8, intestine begins in XV. Typhlosole simple fold one-quarter lumen diameter from XXVII, the intestinal caeca originate in XXVII, simple and extend to XXIII. Oesophageal hearts four pairs in X–XIII. Holandric, testes in X and XI. Seminal vesicles small in XI and large asymmetrical in XII–XIV. Prostate glands extend from XVII to XXI. Prostate duct U shape. Genital marking glands small sessile, corresponding to each external genital marking.

Ovaries paired in XIII. Spermathecae four pairs in VI–IX. Ampulla large sac. Diverticulum long loosely looped, and tufted nephridia present on ducts of the spermathecae in VIII–IX.

Variation. The holotype is 314 mm long with 160 segments; the two paratypes are 215 and 227 mm long with 130 and 135 segments, respectively.

Etymology. This species was named after the type locality, Mt. Phu Chee Fah.

Distribution. The new species is known only from the type locality. Our collections in nearby areas have also found some earthworm species of the genus Metaphire .

Habitat. The new species exhibited swarming in October 2008 at 1,205 m asl, and most of them were juveniles. The reason is still unknown. We collected some specimens by chance. The worms emerged from the top soil of deciduous forest and tried to migrate across a road to another side of the mountain.

Remarks. Amynthas phucheefah , new species, would have been classified in the diffringens species group in Sims & Easton (1972), but the group has been renamed as the corticis species group, which is the most diverse group of the genus Amynthas with more than 90 species names ( Sims & Easton, 1972). Some previously recorded species from Thailand exhibit 4 pairs of spermathecal pores in 5/6–8/9. These are A. alexandri Beddard, 1900 , A. mekongianus ( Cognetti, 1922) , A. exiguus ( Gates, 1930) , A. manicatus ( Gates, 1931) , A. corticis ( Kinberg, 1867) , A. comptus ( Gates, 1932) , and A. longicauliculatus ( Gates, 1931) . Within the corticis species group in Thailand, the first two species lack genital markings, while the current newly described species shows six pairs of genital markings at the male pores lines. The three latter nominal species are smaller in body width (2.5–3 mm) compared with 8.7 mm of the new species and the last two species have genital markings in 18/19–20/21 and prostate glands small and confined to XVIII, and no nephridia on the spermathecal ducts while the new species has six pairs of genital markings in 19/20–24/25, prostate glands in XVII– XXI, and nephridia present on spermathecal ducts ( Table 2).

Figures

Fig. 7. External and internal morphology of holotype (CUMZ 3306) of Amynthas phucheefah, new species: A, external ventral view; B, internal dorsal view; C, spermathecae. Dark arrow indicates the connection of the spermathecae and spermathecal pore.