Pheretima riparianensis, Hong & James, 2021

Hong, Yong & James, Samuel W., 2021, Two new earthworms of the Pheretima sangirensis species group (Clitellata Megascolecidae) from Mountain Province, Philippines, Zootaxa 4995 (2), pp. 357-366 : 358-359

Pheretima riparianensis sp. nov.

( Fig. 1 , Table 1)

urn:lsid:zoobank.org:act:7D477BF0-B196-4122-B1C9-2AAC2C21191A

Material examined. Holotype: Clitellate ( NMA 4629 ): Philippines, Mountain Province, Riparian forest, N. side of Tanudan River (17°05.08’N, 121°08.62’E), 1067 m a.s.l., in soil, 3 April 2001, S.W. James coll. Paratype: 1 clitellate ( NMA 4637 ): same data as for holotype .

Non-types: 2 semiclitellates, same data as for holotype, Mountain Province, on ridge of Mt. Lamagan , 1400– 1500 m a.s.l., in soil, 4 April 2001, S.W. James coll.

Etymology. The species is named for its type locality.

Diagnosis. Dimensions 75–105 mm by 3.7–5.0 mm. Setal numbers 37–43 at VII, 46–58 at XX, 5–7 between male pores. One pair of spermathecal pores in 7/8, copulatory bursae openings 0.11 circumference ventrally apart. Genital markings lacking.

Description. Violet-brown pigment dorsally on all segments, yellowish ventrally, and setal rings of segments I–III unpigmented. Dimensions 75–105 mm by 4.5–5 mm at segment X, 4.5–5 mm at XXX, 4–4.4 mm at clitellum, segments 100–102. Dorsal setae larger than ventral setae, more widely spaced in anterior segments; numbering 37–43 at VII, 46–58 at XX, 5–7 between male pores; setal formula AA: AB: YZ: ZZ = 3: 2: 4: 5.5 at XIII. Clitellum annular XIV–XVI, setae invisible externally. First dorsal pore in 12/13. One pair of spermathecal pores deep in 7/8 at 7th setal line, ventrally placed, 0.07 circumference apart. Female pore single in XIV. Openings of copulatory bursae ca. 0.4–0.5 mm in width, on round or wedge-shaped pads, paired in XVIII at 6th setal line, ventrally placed; ventral distance between two openings ca. 1.7 mm, 0.11 circumference apart. Genital markings lacking.

Septa 5/6, 6/7, 7/8 thin, 8/9, 9/10 incomplete, reduced to a few muscular fibers or absent, 10/11–13/14 slightly muscular, transparent. Gizzard in VIII–X, intestine enlarged from XVI, paired intestinal glands from XXVII along dorsal vessel; intestinal caeca simple originating in XXVII, extending anteriorly to about XXIII, elongate triangular sac; typhlosole low fold 1/6 lumen diameter from XXVII, 22–30 intestinal blood vessels. Hearts in X–XIII esophageal. Ovaries and funnels in XIII. One pair of spermathecae in VII, with nephridia on ducts; spermatheca with small ovate or spherical ampulla, broad and weakly muscular duct shorter than ampulla; seminal chamber pear-shaped, iridescent; diverticular stalk either shorter or longer than ampulla. Male sexual system holandric, testes and funnels in ventrally paired sacs in X–XI. Seminal vesicles two pairs in XI–XII, dorsal lobes ovate, apically attached in shallow clefts, prostates in XVII–XVIII, each gland single cordate mass with a short, muscular duct, entering center of the copulatory bursae without stalked glands; having a ring of small wedge-shaped pads penis a conical protrusion from the roof of the copulatory bursa.

Remarks. Pheretima riparianensis sp. nov. keys to the Pheretima sangirensis species group in Sims and Easton (1972), characterised by having spermathecal pore at 7/8. The P. sangirensis species group is composed of 33 species, of which the following three are from Vanuatu: P. sangirensis ( Michaelsen, 1891) , P. ceramensis Cognetti, 1922 and P. unicystis Lee, 1981 . The first is composed of three subspecies, P. s. chica ( Michaelsen, 1896), P. s. crassicystis ( Michaelsen, 1896) and P. s. sangirensis , of which the taxonomic history is discussed in James (2004b). James (2004b) added ten species to this group: P. quincunxia , P. diesmosi , P. asurgo , P. monoporata , P. vicinipora , P. baungonensis , P. paucisetosa , P. alba , P. rubida , and P. virgata ,all from the Mt. Kitanglad Range, Mindanao Island, Philippines. Hong & James (2008b) reported two new species, P. mariae and P. lagunaensis , from Mt. Makiling, Luzon Island, Philippines. Recently, Aspe & James (2014) described more 11 species, P. maculodorsalis , P. tigris , P. immanis , P. lago , P. nunezae , P.boniaoi , P. malindangensis , P. misamisensis , P.wati , P. longiprostata , and P. nolani from Mt.Malindang Range. More new species were described and assigned to the P. sangirensis species group, including P. timpoongensis , P. camiguinensis , P. sibucalensis and P. apoensis described in Aspe & James (2016), P. floresi , P. baracatanensis and P. solisi group described in Aspe & James (2017)

P. riparianensis sp. nov., P. mariae , P. lagunaensis , P. alba , P. malindangensis , P. longiprostata , and P. sangirensis are the only members lacking septa 8/9 and 9/10 ( Table 1). Pheretima riparianensis sp. nov. is the only one among this set of species with dorsal and ventral setal gaps and spermathecae located in segment VII. Comparing the new species to P. mariae , it has more setae in VII and XX, and fewer intestinal blood vessels ( P. mariae 34–36, P. riparianensis 22–30). Furthermore, P. riparianensis sp. nov. has 5–7 setae between the male pores, while P. mariae has one.

Pheretima riparianensis sp. nov. shares the spermathecal pores in 7/8, setal number and setae between the male pores with P. floresi , P. baracatanensis and P. solisi Aspe & James, 2017 , from Mt. Apo, Mindanao Island. However, three these species differ from Pheretima riparianensis sp. nov. in having spermathecae in VIII (vs. spermathecae in VII), absence of penes (vs. presence of penes).

Figures

FIGURE 1. Pheretima riparianensis sp. nov. (A, B). A: ventral view; B: spermatheca. Scale bars = 2.5 mm (A), 2 mm (B).