Amynthas corticis saeseum

Blakemore, Robert J., 2013, Jeju-do earthworms (Oligochaeta: Megadrilacea) - Quelpart Island revisited, Journal of Species Research 2 (1), pp. 15-54 : 26

Amynthas corticis saeseum sub-sp. nov.

[ Fig. 7 ]

Material examined. Holotype IV0000251310, H (mature figured and dissected providing DNA sample ( WO57 resampled as w33) ; Paratypes IV0000251311, P1-3 (three matures, one posterior amputee dissected), P4 (immature inspected); all from Saeseum Island , Seogwipo, (33̊15′ 10′′N 126̊33′40′′E), collected RJB 13 th June, 2012 from under rocks beside pathway .

Description. Length 100 mm (H). Colour brownish with darker dorsum, clitellum buff on 14-16. Epilobous. First dorsal pore in 12/13. Spermathecal pores in 5/6/7/8/9, ca. 0.3 C apart. Female pore single on 14. Male pores absent, replaced by superfical GMs on 18 with ca. 14 setae intervening. Other genital markings variable: paired or analogue discs posteriomedian to spermatheal pores in 7,8-9, each with stalked glands corresponding internally, some of those in P1 with multiple stalked glands numbering up to three per GM in some cases.

Internally, nephridial forests cover septa in 5 and 6. Spermathecae with wide muscular duct and slightly dilat- ed ampulla with terminal bulb consistently constricted or stalked; diverticulum stunted or with shorter and muscular stalk, the bulb absent or rounded and non-iridescent. Septa 8/9/10 absent around gizzard. Hearts in 10-13. Testis in 10 & 11 (non iridescent), seminal vesicles in 11 & 12. Prostates wholly absent, replaced by small gland, indicative of GM on 18 where male pores would be expected. Oesophagus dilated in 11,12-13. Intestine from 15, caeca simple from 27, typhlosole not noted. Parasites not found.

Remarks. Superficially complying with the nominal taxon, Amynthas corticis saeseum is possibly a ‘proto-species’ distinguished principally by its consistent bulbous augmentation to the spermathecae on either side. Although only parthenogenetic specimens were found indicating a clonal lineage that is only potentially interbreeding (and intrabreeding), here considered equivalent to an allopatric sub-species. Recent phenotypic divergence supported by its DNA barcode complying with some parts of the A. corticis species-complex (WO57 redone as w 33 in Appendix) yet separable by about 3% from “ A. corticis ” specimens identified on Jeju (e.g. w 25 in Appendix) and on the Korean mainland (w59) by the author (Blakemore in prep.). The only other species found on the island was Metaphire californica (IV0000250461 providing DNA WO58 (resampled as w34).

Figures

Fig. 7. Amynthas corticis saeseum sub-sp. nov. holotype showing ventral aspect; prostomium, spermathecae (those on lhs from P1), gland in 18 and caeca in situ with [boxed] enlargement of spermathecae from H and P1 and of male area 18rhs].