Family MEGASCOLECIDAE

earthworm

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Diagnosis

Small (ca 1 cm long) to giant (more than 2 metres long) earthworms. Setae usually four pairs per segment (the lumbricin condition), sometimes six pairs, or more numerous, unpaired (the perichaetin condition), to more than 100. Dorsal pores usually present. Male pores (openings of vasa deferentia) mostly on XVIII, or on XVII or XIX, or, rarely, one or two segments more posterior, or in XVI, paired, rarely single; exceptionally (Hoplochaetella) two pairs. If one pair on XVIII, united with the prostatic pores, or exceptionally (Eudiplotrema) separate. Prostates one to three pairs; when two pairs, usually on XVII and XIX; when three pairs, in XVII, XVIII and XIX. Clitellum multilayered (the crassiclitellate condition), saddle-shaped or, more usually, annular; on three or more of segments XII to XX. Female pores usually a pair on XIV, sometimes homeotically displaced; rarely two pairs, in XIII and XIV. Spermathecal pores pretesticular, usually paired, sometimes unpaired, rarely multiple per segment.

Last hearts in XII or XIII, rarely if ever in the ocnerodrilid location of XI. One to three oesophageal gizzards present, sometimes vestigial or absent. Intestinal gizzards and caeca rare. Extramural diverticula or calciferous glands frequently present; where present not arranged as in the Ocnerodrilidae (not in IX or IX and X) . Intestine commencing between XII and XX. Nephridia a pair per segment (holonephridia), or multiple per segment (meronephridia); some meronephridia may discharge into the foregut or intestine (enteronephry). Testes one or two pairs, usually in X and XI; sometimes enclosed in testis-sacs. Ovaries in XIII (metagyny) or, rarely, in XII and XIII (hologyny); oocytes in several strings. Spermathecae usually paired and with one or more diverticula, sometimes unpaired, rarely adiverticulate. [From Dyne & Jamieson 2004]

Diagnosis References

Dyne, G.R. & Jamieson, B.G.M. 2004. Native Earthworms of Australia II (Megascolicidae, Acanthodrilinae). Canberra, Australia : Australian Biological Resources Study (CD-ROM). [11]

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