Amynthas shimaensis ( Goto & Hatai, 1899 ) Blakemore, 2012

Blakemore, Robert J., 2012, New earthworm species from NIBR’s Jeju-do biosphere compared to historical and new Japanese types (Oligochaeta: Megadrilacea: Megascolecidae), Journal of Species Research 1 (2), pp. 133-150 : 144-145

Amynthas shimaensis ( Goto & Hatai, 1899) comb. nov.

[ Fig. 8].

Perichaeta shimaënsis Goto & Hatai, 1899: 15 , fig. 3, tab. 1. Shima, Kai Peninsula. Type (s) unknown. Pheretima shimaensis : Michaelsen, 1900: 303.

Material examined. Single mature specimen unregister- ed in Yokohama National University ( YNU) SERG earthworm collection, from high mountain plains, Mt Fuji, Shizuoka-ken, Japan collected 8 th November, 1998 by To-

10

Amynthas shimaensis moko Uchida.

Description. Dark grey dorsum with intersegments not noticeably darker nor paler, clitellum puce in Fuji specimen versus dark flesh colour with darker intersegments in Goto & Hatai’s specimen. Length 150 mm with 132 segments (205 and 163 segments in Goto & Hatai). First dorsal pore in 12/13 (Fuji specimen and Goto & Hatai’s account). Setae ca. 50 before clitellum and ca. 60 after in Fuji specimen (Goto & Hatai have about 85 in the genital segments). Spermathecal pores four pairs in 5/6/7/8/9 about 0.25 of circumference apart. Male pores superficial on segment 18 with about 10-13 setae intervening (Goto & Hatai have them separated by 13 setae but only show 11 in their fig. 3). Genital markings paired posteriorly in 19 encroaching in 19/20 with solid gland corresponding internally. Septa 8/9 and 9/10 aborted. Spermathecal diverticula clavate and convoluted (or “winding” in Goto & Hatai). Last hearts in 13. Holandric with seminal vesicles in 11 & 12. Intestine from 15; intestinal caeca from 26 or 27 simple with incised ventral margins (in Fuji specimens at least). Lamellar typhlosole from ca. 27 (pers. obs.).

Distribution. Japan, Mie-ken, Kansai [that Easton (1981: 55) mistakes as “GUMMA” (=Gunma-ken) in Kanto], and now possibly Mt Fuji in Shizuoka-ken.

Remarks. Amynthas shimaensis ( Goto & Hatai, 1899) is restored from synonymy in A. micronarius ( Goto & Hatai, 1898) . However, the major problem now is that the only difference between A. shimaensis and the prior Amynthas grossus ( Goto & Hatai, 1898: 75) - provisionally in synonymy of A. fuscatus ( Goto & Hatai, 1898: 66) after Easton (1981: 57) along with ten other synonyms from Blakemore (2003: 19) - is posterior markings additional to those in 19 (or absent). Both taxa typically have winding spermathecal diverticula. Although not mentioned by Goto & Hatai, all these species appear to share incised intestinal caeca, at least in mature worms and, accepting this, the current specimen agrees tolerably with their description of A. shimaensis . Proper resolution requires new material from its Shima, Mie-ken type-locality.

Alternatively, this Fuji specimen may actually correspond to Amynthas grossus once it is separated and remov- ed from A. fuscatus , but such acts are deferred pending further studies from Japan.

Korean Amynthas murayamai ( Kobayashi, 1938: 164) is distinguished from A. shimaensis redescribed here, in its GMs anteriorly on 19 with no setae intervening, amongst other differences; also its intestinal caeca are smooth edg- ed. Thus it is maintained on the Korean biodiversity list.