New Polypheretima and Pithemera (Oligochaeta: Megascolecidae) species from the Mt. Malindang Range, Mindanao Island, Philippines

Abstract

We describe four new pheretimoid earthworm species, one in Polypheretima and three in Pithemera, from Mt. Malindang, Misamis Occidental Province, Mindanao Island, Philippines, and provide diagrams of external morphology and internal anatomy. Polypheretima mindanaoensis sp. nov. belongs to the Po. elongata species group, characterised by having genital markings on xix and successive segments and pairs of spermathecal batteries in vi and/or vii. It differs from the other members of the Po. elongata species group in having no copulatory bursae. This species shows individual variation in the number of spermathecae in each battery. Individuals that lack spermathecae are presumed to reproduce parthenogenetically. Pithemera malindangensis sp. nov. and Pi. duminagati sp. nov. belong to the Pi. bicincta species group, characterised by having the first spermathecal pores in 4/5. These two species differ in size and in the distance between male pores. Pithemera donvictorianoi sp. nov. belongs to the Pi. pacifica species group, characterised by having the first spermathecal pores in 5/6. This is the only member of this species group so far reported from the Philippines, and this is the only Philippine Pithemera species whose clitellum covers two rather than two and a half segments. Current studies show that worldwide, the Philippines has the highest diversity for Pithemera, with 13 species, followed by Papua New Guinea and the Pacific Islands, each area with six species. Indonesia has the highest diversity for Polypheretima, with 18 species, followed by Vietnam with 13 species, and then Papua New Guinea and the Philippines, each area with eight species. These findings indicate a high degree of endemicity within these areas, suggesting that many species remain to be detected in the Philippines.http://zoobank.org/urn:lsid:zoobank.org:pub:2198709C-F5E1-4A0D-A185-CA506D206171