Metaphire khaoluangensis 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 : 71-73

Metaphire khaoluangensis Bantaowong & Panha , sp. n.

( Figure 6 , Table 2 )

Material examined. Holotype: clitellate ( CUMZ 3377), Thailand, Nakhon Si Thammarat, Nopphitam, Ban Khlong Phod, a village in the Khaoluang mountain range, 8°48'8.4"N, 99°35'18.6"E, 140 m amsl, 17 January 2013, leg. U. Bantaowong, C. Sutcharit & W. Siriwut. Paratypes: 22 adults ( CUMZ 3378), 2 adults ( ZMH), 2 adults ( NHMUK), same data as holotype.

Other material examined. Two adults ( CUMZ 3379), Thailand, Nakhon Si Thammarat, Nopphitam, Krungching Waterfall, 8°43'34.8"N, 99 39'58.4"E, 208 m amsl, 17 January 2013. 9 adults ( CUMZ 3380), Thailand, Nakhon Si Thammarat, Nopphitam, Tham Lod, 8°47'17.2"N, 99°38'40.1"E, 97 m amsl, 17 January 2013. 4 adults ( CUMZ 3381), Thailand, Phatthalung, Srinagarindra, Tham Phutthakodom, 7°33'38.5"N, 99°53'5.6"E, 54 m amsl, 16 January 2013.

Diagnosis. Medium-sized; length 130–265 mm with 113–132 segments. Setae numbering 36–47 in VII, 49–59 in XX, 10–14 between male pores. Male pores paired, secondary opening with puckered margin on segment XVIII, no genital markings. Spermathecal pores paired in segments 6/7–8/9. Ampulla elongate sac-like, with short duct, diverticulum slender, constricted with round seminal chamber. No nephridia on the spermathecal duct. Holandric, intestinal caeca simple, first dorsal pore in 12/13. Prostate glands well developed, its duct embed in the copulatory sac.

Etymology. This new species was named after Mt. Khaoluang where it was collected.

Description of holotype. Dimensions 220 mm length by 10.0 mm width at segment VII, 9.0 mm at XX, 9.0 mm at clitellum; body cylindrical with 119 segments. Preserved specimen reddish-brown on head and dorsum, light-brown ventrally, and darkish purple-brown around clitellum. Setae regularly distributed around segmental equators, numbering 36 at VII, 51 at XX, 14 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 12/13. Clitellum annular XIV–XVI. Male pores conspicuous, secondary openings with puckered margin, separated from each other by 0.28 circumference ventrally, distance between openings of copulatory pouches 7 mm. Spermathecal pores three pairs in 6/7–8/9, epidermis around each pore slightly wrinkled, about 0.44 circumference apart ventrally, distance between spermathecal pores 11 mm on body circumference.

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, extending to XXI. Typhlosole 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 gland occupying segments XVI to XIX. Prostatic duct slightly muscular, closely attached to lateral side of copulatory sac. Ovaries in XIII. Three pairs of spermathecae in VII–IX. Ampulla elongate, sac-like, with short duct; diverticulum slender, its proximal end with a neck-like constriction; total length slightly less than ampulla.

Variation. Body length of paratypes 130–265 mm (211.6±22.6), segments 113–131. Prostate glands in XVI– XX, intestinal caeca often shorter than in holotype, ending in XXIII.

Distribution. Known from the type locality and one additional locality in Phatthalung province, the two sites being separated by approximately 240 km.

Remarks. This species is sexthecal, with spermathecal pores on 6/7–8/9, and devoid of postclitellar genital markings, so it belongs to the houlleti species group which is one of the largest species groups in Metaphire , with more than 30 species ( Sims & Easton 1972). In the following we will compare the new species with regional species in the houlleti group: M. umbraticola ( Gates, 1932) and M. quadrigemina ( Gates, 1932) from Myanmar, M. amplectens ( Michaelsen, 1934) and M. dawydovi ( Michaelsen, 1934) from Vietnam, and M. bindjeyensis ( Michaelsen, 1899) from Sumatra.

Metaphire khaoluangensis sp. n. is similar to M. umbraticola , M. dawydovi and M. bindjeyensis by the aspect of the secondary male openings and the body size. They differ in the spermathecae. M. umbraticola has oval ampullae with long diverticulum, M. bindjeyensis has obclavate ampullae with zigzag diverticulum, and M. dawydovi has flask-shaped ampullae with small diverticulum, while M. khaoluangensis sp. n. has elongate sac-like ampullae with capitate diverticulum.

In Thailand, only three species of this group have been reported, M. houlleti ( Perrier, 1872) , M. virgo ( Beddard, 1900) , and M. perichaeta ( Beddard, 1900) . Metaphire khaoluangensis sp. n. can be distinguished from the first two species by the distance between the openings of the copulatory pouches, measured as a fraction of the estimated body circumference. This measure is 0.28 in M. khaoluangensis sp. n., but 0.30 and 0.33 in M. houlleti and M. virgo , respectively ( Beddard 1900). Other differences from M. houlleti and M. virgo are: first dorsal pore in 12/13 (11/ 12 in M. houlleti and M. virgo ) and spermathecal ampulla large and elongate (spherical and small sac in M. houlleti and M. virgo , respectively). The new species does not have the contorted diverticulum stalk enveloped in connective tissue as found in M. houlleti , and also lacks the typhlosole present in M. houlleti . M. virgo is further distinguished from the new species by a spermathecal diverticulum stalk with multiple folds. Both M. houlleti and M. virgo have genital markings bearing stalked glands in association with spermathecae and with the copulatory sacs, whereas the new species lacks these characters. This new species is fairly similar to M. perichaeta in male pore spacing (0.28 body circumference), but it is distinguished by elongated spermathecae with slender diverticulum and last hearts in XIII, compared to inverted pear-shape spermathecae with coiled diverticulum and last hearts in XII in M. perichaeta ( Beddard 1900; Stephenson 1932). A comparison of characters between M. khaoluangensis sp. n. and other related species is presented in Table 2 .

Figures

FIGURE 6. External and internal morphology of Metaphire khaoluangensis sp. n., holotype (CUMZ 3377). A. External ventral view. B. Internal dorsal view. C. Spermatheca; arrowhead: location of spermathecal pore.