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Volume 79, 1951
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“Chaetae six pairs per segment. One oesophageal gizzard in one simple segment. Calciferous glands as mere dilatations of the oesophagus in the region of xiv–xvii (? always). Purely micronephridial. Sexual apparatus purely acanthodriline.” (Stephenson, 1930.)

The genus is confined to New Zealand and four species have been described by previous workers [including D. (Conicodrilus) kanieriensis]. These four species are:

  • D. benhami Beddard (1890)

  • D. suteri Benham (1905)

  • D. gracilis Ude (1905)

  • D. kanieriensis Benham (1945)

To these four species must now be added the three new species D. agilis, D. montanus and D. parvus, which are described in this paper.

The species of Dinodrilus may be identified from the following key:

a1 Eight chaetae on each segment anterior to clitellum, twelve on each of the remaining segments D. kanieriensis
a2 Twelve chaetae on each segment throughout
  b1 No calciferous glands
    c1 Gizzard in v D. parvus
    c2 Gizzard in vi D. montanus
    c3 Gizzard occupying vi and vii
      d1 Spermatheca with three ovoidal diverticula D. benhami
      d2 Spermatheca with six digitate diverticula D. gracilis
  b2 Two pairs of calciferous glands in xvi and xvii D. suteri
  b3 Five pairs of calciferous glands in ix, x, xi, xii and xiii D. agilis

D. agilis, by its possession of five pairs of calciferous glands, falls outside the definition of the genus. However, the definition may be extended to include such a variation.

The presence of only eight chaetae on each of the preclitellar segments of D. kanieriensis gives this species some claim to inclusion in the genus Octochaetus, but in all other respects the species closely resembles D. gracilis and has been included in the genus Dinodrilus.

The following are descriptions of the three new species, D. parvus, D. montanus, and D. agilis. Type specimens in the author's collection.

Dinodrilus parvus n.sp. (Plate 118, figs. 1–3)

Several specimens of this species were collected from the topsoil of Awapuka clay loam, under dense native bush, near the summit of

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the Mangamuku Range, south of Kaitaia. The specimen on which this description is based is 32·5 mm. long, 4 mm. in diameter, and has 113 segments.

The prostomium is tanylobous. The clitellum is darker in colour than the adjacent segments and surrounds xii to xvi. Chaetae commence on ii and there are twelve on each segment, arranged in pairs. On xxii their arrangement is as follows:

ab = cd = ef = 1 mm.; aa = 1·5 mm.; ff = 1·5 mm.; bc = de = 1·25 mm.

There are two pairs of spermathecal pores, a pair at 7/8 and a pair at 8/9. Each pore is in line with the chaetal interval ab on the same side. A single pair of female pores is present on xiv. The pore on each side is situated anterior to chaeta a. There are two pairs of prostatic pores, a pair on xvii and a pair on xix, situated on prominent rounded papillae. Each prostatic papilla lies in line with the chaetal intervals ab on the same side. The prostatic pores of each side are joined by a longitudinal groove which traverses xviii. A male pore is present in each groove on xviii between the chaetae a and b.

There are no nephridiopores. Dorsal pores commence at 12/13.

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