Aulodrilus Bretscher, 1899

Ohtaka, Akifumi, 2021, Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species, Zootaxa 4952 (1), pp. 1-32 : 2

Genus Aulodrilus Bretscher, 1899

Type species. Aulodrilus limnobius Bretscher, 1899

Diagnosis. Medium sized worms with numerous chaetae (up to 16 in ventral bundles) and unsegmented tails. Short and slightly sigmoid hair chaetae present or absent. Lateral wings on crotchet chaetae present or absent. Vasa deferentia usually about as long as atrium, with uniform width, connected to apical end of atrium. Atria globular to tubular in shape, laterally joined by a solid, single prostate gland through a short stalk. Protrusible, true penes usually present without cuticular sheaths or eversible pseudopenes. Loose sperm masses in spermathecae, not forming spermatozeugmata. Coelomocytes sparse or absent. Duplication and forward shift of genital organs often occur. Single embryo in cocoon. Dwelling in mud tubes. The diagnosis is modified from Brinkhurst (1971), Hrabě (1981) and Finogenova and Arkhipova (1994).

Remarks. Brinkhurst (1971) listed three diagnostic characters of the genus Aulodrilus by which he afforded subfamilial rank: 1) prostates attached to atria by broad bases, 2) sperm in bundles (masses) in spermathecae, 3) coelomocytes absent. Subsequently Giani et al. (1984) corrected the first feature, because prostate glands of A. pluriseta and A. limnobius are stalked on the atrium like those of Tubificinae , and they invalidated the subfamily Aulodrilinae . At the genus level, along with other two characters listed above, short vas deferentia, globular or cylindrical atria, large eversible pseudopenes, and unsegmented posterior ends have been used as diagnostic characters ( Brinkhurst 1971; Hrabě 1981; Finogenova & Arkhipova 1994). Finogenova and Arkhipova (1994) emphasized a forward shift of reproductive organs and multiplication of gonads as diagnostic characters of Aulodrilus .

It is reasonable to regard the subfamily Aulodrilinae invalid and to maintain the genus Aulodrilus in the subfamily Tubificinae . Among Tubificinae , lateral expansions of somatic chaetae occur only in this genus; however, not all congeners have this feature, and species also vary in expression of the other characters listed above. The genusdiagnostic characters of Aulodrilus are evaluated in the "Discussion".