Metaphire doiphamon Bantaowong & Panha

Bantaowong, Ueangfa, Chanabun, Ratmanee, James, Samuel W. & Panha, Somsak, 2016, Seven new species of the earthworm genus Metaphire Sims & Easton, 1972 from Thailand (Clitellata: Megascolecidae), Zootaxa 4117 (1), pp. 63-84 : 76-78

Metaphire doiphamon Bantaowong & Panha , sp. n.

( Figure 9 )

Material examined. Holotype: clitellate ( CUMZ 3390), Thailand, Chiang Rai, Thoeng, Phu Chee Fah, Doi Phamon mountain range, 19°48'47.0"N, 100°26'20.4"E, 1205 m amsl, leg. U. Bantaowong, C. Sutcharit, & P. Tongkerd, 19 November 2012. Paratype: 1 adult ( CUMZ 3391), same data as holotype.

Etymology. This species is named after the Doi Phamon mountain range, where it was collected. Noun in apposition.

Diagnosis. Large Metaphire worms; length 255–269 mm with 142 segments. Setae numbering 44–49 in VII, 84–89 in XX, 21–22 between male pores. Male pores paired, transverse secondary openings in XVIII, genital markings paired on 17/18 and 18/19. Spermathecal pores paired in 6/7–8/9. Spermathecae with ovoid ampulla, diverticulum thread-like, slightly curved at tip. No nephridia on the spermathecal ducts. Holandric, intestinal caeca simple, first dorsal pore in 12/13. Prostate glands and ducts two branches, with white glandular mass on body wall where duct ends.

Description of holotype. Dimensions: 255 mm by 9.9 mm at segment VII, 11.0 mm at segment XX, 10.0 mm at clitellum; body cylindrical with 142 segments. Preserved specimen dark to grayish-brown dorsally, ventrally pale; clitellum with light brownish purple colour. Setae regularly distributed around segmental equators, numbering 49 at VII, 84 at XX, 21 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 three rows of setae.

Secondary male apertures as two transverse openings situated on ventro-lateral sides of XVIII, about 0.26 circumference apart ventrally, distance between male apertures 8 mm, each male pore in a very shallow rudimentary copulatory chamber, the whole male area surrounded by 3–4 closely adjacent concentric circular ridges. Genital markings paired, transversely elliptical, 4–5 intersetal intervals wide, located in intersegments of 17/18 and 18/19, in line with male apertures. Three pairs of spermathecal pores, transverse slits in furrows 6/7–8/9, ventral, distance between each pair 9 mm on body circumference, about 0.30 body circumference apart ventrally.

Septa 5/6–7/8 thick, 8/9–9/10 absent, 10/11–11/12 thin. Gizzard large behind 7/8, intestinal origin XV; intestinal caeca originating in XXVII, simple and extending to XXII. Typhlosole simple, rudimentary. Oesophageal hearts four pairs in X–XIII. Holandric; testes two pairs in ventrally joined sacs in X and XI. Seminal vesicles paired in XI–XII. Prostate glands usually confined to XVII–XIX, separated into two racemose lobes. Prostatic duct divided into two small branches, one per lobe. Paired, white glandular masses on copulatory sac, where prostatic ducts enter the parietes. Ovaries in XIII. Spermathecae three pairs in VII–IX. Ampulla ovoid, duct stout, one-third as long as ampulla and sharply marked off from ampulla. Diverticulum long and slender, thread-like, without a terminally enlarged seminal chamber, slightly curved at tip.

Variation. The single paratype specimen measures 269 mm in body length, with 142 segments.

Distribution. This species is known only from the type locality, where it coexists with Amynthas phucheefah Bantaowong & Panha, 2014 .

Remarks. Metaphire doiphamon sp. n. is sexthecal and presents genital markings at 17/18 and 18/19, so it keys out with the peguana group, which consists of three other species, M. bahli ( Gates, 1945) , M. peguana ( Rosa, 1890) and M. saigonensis ( Omodeo, 1957) . Of these, M. peguana and M. bahli have been recorded in Thailand, whereas M. saigonensis is currently placed in synonymy with M. peguana ( Blakemore 2002; Somniyam & Suwanwaree 2009; Bantaowong et al. 2011b; Prasankok et al. 2013).

This new species is distinguished from the other members of the species group by its body length of 255 mm, the form of the genital markings and the bifurcate prostatic ducts. The genital markings are transversely oval in M. doiphamon sp. n., they lack pores or other openings and are associated with sessile glandular masses on the copulatory pouch, while the genital markings of M. peguana and M. bahli are circular to oval, invaginated or pouch-like, and with stalked glands. Both of them have a smaller body size (range of 110–240 mm) and fewer segments. Furthermore, M. doiphamon sp. n. also has unique prostate glands and ducts, being divided into two main lobes each with a large and long duct, while the two former species have regular prostate glands, each consisting of a single racemose mass with many small ductlets.

Figures

FIGURE 9. External and internal morphology of Metaphire doiphamon sp. n., holotype (CUMZ 3390). A. External ventral view. B. Internal dorsal view. C. Spermathecae; arrowhead: location of spermathecal pore.