Perionyx excavatus Perrier, 1872 Description: Length 20–120 mm. Unpigmented or slightly red dorsally, slightly yellow at ventral side. Prostomium epilobous. First dorsal pore in some of the intersegmental furrows 2/3–5/6. Nephropores conspicuous, in irregular lines. Spermathecal pores paired, in intersegmental furrows 7/8–8/9 respectively. Female pore single, mediventral. Male pores paired, in 18. Clitellum on 13–17. Gizzard present or absent. Intestinal origin in 15–16. Small parts of calciferous tissues may occur in segment 13, 14 or 15. Last lateral heart in 12. Excretory system holoic, avesiculate. Seminal vesicles in 11 and 12, last pair often extended through septa 12/13–14/15. Prostates in 18, ducts short, straight. Spermathecae paired, large with short ducts. Penial setae present. Notes: Distributed widely worldwide. May be found under the bark of rotten, fallen logs; under moss and debris; on riverbanks; in soil rich in organic matter; in manure heaps and composting areas; and in any considerably moist biotope. Recently used in vermicomposting farms. In RSA breeding is possible under favourable climatic conditions. This species was used in various experiments by Reinecke et al. (1992), and Reinecke and Pieters (1997, 1998), and may be found near previous experimental fields.

{"references": ["PERRIER, E. 1872. Recherches pour servir a l'histoire des lombriciens terrestres. Nouvelles Archives du Museum d'Histoire Naturelle, Paris 8: 5 - 198.", "REINECKE, A. J, VILJOEN, S. A. & SAAYMEN, R. J. 1992. The suitability of Eudrilus eugeniae, Perionyx excavatus and Eisenia fetida (Oligochaeta) for vermicomposting in southern Africa in terms of their temperature requirements. Soil Biology and Biochemistry 24 (12): 1295 - 1307.", "REINECKE, S. A. & PIETERS, R. 1997. The morphology of male reproductive structures of Perionyx excavatus (Oligochaeta). South African Journal of Zoology 32 (3): 64 - 71."]}

Published as part of Plisko, Jadwiga D. & Nxele, Thembeka C., 2015, An annotated key separating foreign earthworm species from the indigenous South African taxa (Oligochaeta: Acanthodrilidae, Eudrilidae, Glossoscolecidae, Lumbricidae, Megascolecidae, Microchaetidae, Ocnerodrilidae and Tritogeniidae), pp. 663 in African Invertebrates 56 (3) on page 700, DOI: 10.5733/afin.056.0312, http://zenodo.org/record/7914712