Diversity & Evolution 3 (2003)
Electronic Supplement 11
Robert J. Blakemore:
Japanese earthworms (Annelida: Oligochaeta): a review and checklist of species.
print version: Org. Divers. Evol. 3(3): 241-244. 2003 (abstract +
electr. suppl.: full article. pdf-format, 589 KB
The current revision provisionally lists 77 valid earthworm taxa in seven families from Japan, with approximately 80 further names (ca. 50% of the total) either in synonymy - including 73 new synonyms - or retained as species incertae sedis. Generic placement of the species yielded 17 new combinations. About 30 species are known introductions and another ten are possibly more widespread, thus the probable number of wholly endemic Japanese earthworms is around 40 species (ca. 50% of the total valid species). However, a definitive work on the systematics of Japan's earthworms is pending, and the current revision aims only to provide a status quo and to track changes from the last comprehensive revision by Easton (1981) that listed 74 taxa. Subsequently, 60 or so new pheretimoid names were added by Ishizuka in 1999-2001, but only a few are considered valid taxa, the remainder being synonyms or species incertae sedis. The substitute name 'Pheretima' palarva, nom. nov., is provided for the junior homonym Pheretima parvula Ishizuka et al., 2000. While much of Easton's synopsis is supported, Pontodrilus is now placed in Megascolecidae sensu Blakemore (2000) rather than Acanthodrilidae sensu Gates (1959); Amynthas carnosus (Goto & Hatai, 1899) is removed from synonymy with Amynthas gracilis; and an informal Amynthas corticis species-complex is established to accommodate the various morphs of this widely distributed species group. Pheretima (Parapheretima) koellikeri Michaelsen, 1928 is considered synonymous with Metaphire vesiculata (Goto & Hatai, 1899), thereby removing the genus Pheretima sensu stricto from the Japanese list. Polypheretima is also removed from Japanese indigeny, as the original description of Polypheretima iizukai (Goto & Hatai, 1899) failed to report intestinal caeca, and inspection of fresh material allows its placement in synonymy with Amynthas fuscatus (Goto & Hatai, 1898). Easton (1981) had listed this taxon as Metaphire fuscata, but further demonstration of superficial male pores qualifies it for Amynthas. Conversely, the discovery of copulatory pouches results in transfer from Amynthas to Metaphire for M. hilgendorfi (Michaelsen, 1892), comb. nov., Metaphire communissima (Goto & Hatai, 1898), comb. nov., and Metaphire megascolidioides (Goto & Hatai, 1899), comb. nov. The Metaphire hilgendorfi / Amynthas tokioensis species-complex (Amynthas hilgendorfi species-complex sensu Easton 1981) remains one of the most intractable and pressing problems for comprehension of the Japanese fauna, as most of the component taxa, e.g. Metaphire agrestis (Goto & Hatai, 1899), are parthenogenetically degraded morphs as yet unaffiliated with their ancestral and biparental populations. Resolution may be sought employing combinations of morphological and molecular (RNA, DNA) techniques to determine specific affinities while also complying with requirements of the International Code of Zoological Nomenclature (ICZN 1999).
Key words: taxonomy, Pheretima, Metaphire hilgendorfi, Amynthas tokioensis, A. corticis species-complex, parthenogenetic polymorphism