Metaphire surinensis 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 : 81-82

Metaphire surinensis Bantaowong & Panha , sp. n.

( Figure 12 )

Type material. Holotype: clitellate ( CUMZ 3395), Thailand, Surin, Sangkha, Pasonnongkoo Forest Park, 14°41'12.0"N, 103°44'47.9" E, 165 m amsl, 16 October 2012, leg. U. Bantaowong, C. Sutcharit, R. Chanabun, J. Taptimon & W. Siriwut. Paratypes: 2 adults ( CUMZ 3396), 1 adult ( ZMH), 1 adult ( NHMUK), same data as holotype.

Etymology. The specis is named after Surin, the province where it was collected.

Diagnosis. Large Metaphire worms; length 275–300 mm with 153–190 segments. Setae numbering 112–130 in VII, 128–142 in XX, no setae between male pores. Copulatory pouches invaginated in a single deep transverse body wall invagination in segment XVIII, genital markings closely paired, protuberant in 18/19. Spermathecal pores closely paired in 6/7. Spermathecae with elliptical ampulla, diverticulum long, slender, with sausage-like seminal chamber. Holandric, intestinal caeca simple, first dorsal pore in 11/12. Prostate glands large, posterior to copulatory sacs, ducts slender, joining large circular copulatory sac near its center; large genital marking gland posterior to each copulatory sac.

Description of holotype. Dimensions: 275 mm by 8.8 mm at segment VII, 9.2 mm at segment XX, 9.0 mm at clitellum; body cylindrical with 190 segments. Preserved specimen brownish-red dorsally, light-gray ventrally; clitellum light-brown. Setae regularly distributed around segmental equators, numbering 123 at VII, 128 at XX, no setae 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 11/12. Clitellum annular XIV–XVI.

Male pores in copulatory pouches, these, together with their apertures, enclosed in a single, deep, transverse body wall invagination; pouches invisible from the outside. Apertures of pouches inside invagination, 0.15 circumference apart ventrally, equalling 5 mm. Genital markings huge, closely paired, protuberant in 18/19. One pair of spermathecal pores, very closely paired, each on a tiny tubercle, in furrow 6/7, ventral, distance between paired pores about 0.05 body circumference, distance between spermathecal pores 1.5 mm.

Septa 5/6–7/8 thick, 8/9–9/10 absent, 10/11–11/12 thin. Gizzard large behind 7/8, intestinal origin in XV, intestinal caeca originating in XXVII, simple and extending to XXIII. Typhlosole a simple fold, one-fourth of the lumen diameter, beginning in XXVII. Oesophageal hearts four pairs in X–XIII. Holandric; testes and funnels enclosed in paired sacs in X and XI. Seminal vesicles two pairs in XI–XII, large but not conjoint mid-dorsally, nearly equal in size and in shape. Prostate glands well-developed, large, extending anteriorly to segment XX, posteriorly to XXVII. Prostate duct very long, of sigmoid shape, copulatory pouches in segment XVIII. Genital marking glands, paired cushion-like glandular masses, possibly protrusible externally. Ovaries in XIII. One pair of spermathecae in VII. Ampulla elliptical. Terminal chamber of diverticulum sausage-like, longer than ampulla, remarkable in being slightly larger than the ampulla.

Variation. The two paratypes are 208 and 330 mm long and with 153 and 169 segments, respectively. One paratype has a pair of genital markings on 17/18, with prostate glands situated on segments XVIII–XXI. The other paratype shows long prostate glands in segments XVIII–XXXIII.

Distribution. This species is known only from the type locality. They live in the soil at about 20–30 cm depth, in a forest park.

Remarks. The only bithecal species of the genus Metaphire known to date that has the spermathecal pores at 6/7 is M. ladjangensis ( Ude, 1932) . Differences between M. surinensis and M. ladjangensis are primarily in the body size, male field and the location of genital markings. Metaphire ladjangensis is a quite small earthworm, 70 mm in body length and 95 segments while M. surinensis has length 275–300 mm with 153–190 segments. The secondary male pores of M. ladjangensis are small, visible from the surface and have 14 setae between them, but in M. surinensis they are in a deep invagination of the body wall with no setae between them. Moreover, in M. ladjangensis the genital markings are situated on segment VIII and intersegments 17/18–18/19, and male pores are 0.30 body circumference ventrally apart, while in M. surinensis the genital markings are situated on intersegment 18/ 19 in the holotype and the distance between openings of copulatory pouch is about 0.15 circumference.

Figures

FIGURE 12. External and internal morphology of Metaphire surinensis sp. n., holotype (CUMZ 3395). A. External ventral view. B. Internal dorsal view. C. Spermatheca; arrowhead: location of spermathecal pore.