Two new Korean earthworms (Annelida, Oligochaeta, Megadrilacea, Megascolecidae)

Abstract Two Korean endemic pheretimoid Amynthas Kinberg, 1867 species belonging in family Megascolecidae s. stricto are sketched, dissected and described. Amynthas daeari Blakemore sp. n. has spermathecae in 6/7/8 complying with an Amynthas tokioensis spp-group, whilst Amynthas jinburi Blakemore sp. n. has spermathecal pores in 5 & 6 strictly complying with Sims and Easton’s (1972) Amynthas canaliculatus-group. A definitive COI gene barcode is provided for the holotype of Amynthas daeari but the age since collection or preservation of the Amynthas jinburi type in 2000 precluded its mtDNA extraction at this time.


introduction
Specimens from the collection of NIBR contribute to ongoing earthworm surveys as part of understudied non-insect invertebrates of the Korean Peninsula (Blakemore 2012a, b, 2013a, b, Blakemore et al. 2012a. Two specimens are described below belonging to a pheretimoid (Pheretima auct.) group of Oriental origin that provides approximately 970 valid species from 1,200 nominal taxa (Blakemore 2008a). Amynthas Kinberg, 1867 is the most diverse of the pheretimoid genera with some species common to Korea and Japan where faunal totals both approach 100 megadrile earthworm taxa (Blakemore 2003(Blakemore , 2008b(Blakemore , c, 2012c. The probable endemics are here added to the Korean list.

Materials and methods
Taxonomic determinations follow the methodology and classifications in Sims and Easton (1972) and Blakemore (2010). Abbreviations are: C -circumference, GMsgenital markings, lhs -left hand side and rhs -right hand side.
Specimens, now in 80% Ethanol, are lodged in the NIBR facility. Small tissue samples taken for mtDNA COI barcoding as proposed 10 yrs ago by Hebert et al. (2003) used similar methods as per Blakemore et al. (2010) with preliminary analysis via BLAST programs (www.blast.ncbi.nlm.nih.gov/BLAST.cgi).
Discussion is confined to remarks after each species' description. For brevity, not all taxonomic authorities are cited in References as these may be sought elsewhere.

Diagnosis.
Amynthas with two pairs of spermathecal pores in 6/7/8 complying with an A. tokioensis -group; spermathecae with compressed clavate diverticula; GMs median to spermathecal and male pores with patches around the former and the latter bracketed laterally by small C-shaped clefts.
Distribution. Only known from a single specimen from type locality. On 18 centred on small, round porophore (found by following a pin from prostate gland exit) with GMs anterio-median and shallow clefts laterally (that function as seminal ducts and/or suction cups?).
Female pores. Single on 14. Spermathecal pores. 6/7/8 ca 0.3 C apart at edge of puckered area and lateral to GMs. Genital markings. Paired discs just median to male and spermathecal pores as noted; composite glands on spermathecal pore GMs but none found for GMs near male pores although the body here is macerated and they may well have broken off and dissipated.

Dorsal blood vessel (dbv
Prostates. Racemose glands in 17-19, duct short and muscular. Spermathecae. Two pairs in 7 and 8; that in 7lhs inflated, that in 8lhs deflated (showing how meaningless such a distinction is although relied on by some authors).

CTATATTTCATTTTAGGAATTTGAGCTGGAATAATTGGGGCAG-G A A T A A G A C T G C T T A T T C G A A T T G A G C T A A G A C
megaBLAST result: "Amynthas tappensis" (AB542547.1) from Japan max. identity <88% this then is a different and likely new taxon. The closest match from current Korean studies with BLASTn identity 565/653 (87%) is WO49, an immature Amynthas sp. from Jeju that itself comes closest to the A. tokioensis/M. hilgendorfi spp. complexes (see Blakemore, 2013a: Appendix).
Remarks. Of Amynthas species with spermathecae in 6/7/8, twenty or so in the Amynthas tokioensis-group of Sims and Easton (1972) mostly have manicate caeca, such as A. kanrazanus (Kobayashi, 1937); about twenty other species, many placed in this group after 1972, have simple intestinal caeca. Only four have simple incised caeca as here, but they all differ in characteristics of their GMs, at least, and none of these latter are known from Korea (Blakemore unpublished). The incised caeca is assumed to be a characteristic transitional or intermediate from simple to complex/manicate. The GMs in 7-8 obviously correspond to those in 18 during amphimixis but it is not known whether they interlock serially. The shape of the spermathecae and spermathecal pores are further distinguishing characteristics of A. daeari that, along with its objective DNA barcode data, now serve to define this taxon.
Etymology. Noun from location. Diagnosis. Amynthas with two pairs of spermathecal pores in 5 & 6; long, clavate spermathecal diverticula; simple caeca; and GMs absent except for large patches surrounding male pores.
Distribution. Known only from single specimen from type locality. Habitat. Jinburi is a remote, mountainous and forested area Behaviour. Possibly deep burrowing and geophageous (from gut contents). Description. Length. 210 mm. Width. ca. 10 mm at male pore level. Segments. 143 with some secondary annulation (from preservation?).
Prostates: Racemose glands not fully developed in 18 on short, muscular duct. Spermathecae. Two pairs in 6 & 7 exiting to anterior of 5/6 and 6/7 in 5 & 6 ( Fig. 2). Gut contents. Filled with yellow soil, i.e. probably a deep-burrowing subsoil geophage. DNA COI barcode. >w61b -nil result, DNA not extractable on this older material that may have been fixed in formalin (although there was no odour) or denatured by pH.
If spermathecal pores were in 5/6/7 in any of the above taxa, then the morrisigroup's possible nearest relatives from Korea would likely be A. koreanus (Kobayashi, 1938: 115) that, however, has manicate caeca; or A. kobayashii (Kobayashi, 1938: 119) and A. geojeinsulae (Song & Paik, 1970) that both have male fields from 17-19 but differ in simple or incised caeca, respectively; or A. assimilis Hong & Kim, 2002 that, like many of its similar cited taxa, has seminal grooves on 18.
The current species has simple, superficial male pores on large disc-like pads on 18. Although not fully mature, it appears unique in the Korea fauna on its combination of this aspect of its male field, spermathecal pores in 5 & 6 and its profusion of setae that number more than 100 per segment, combined with simple elongate intestinal caeca.
Fresh topotypic material is required to confirm these conclusions and to provide definitive DNA data, unless refinement of techniques allows extraction from older types.