Deinodrilus orcus, Blakemore, 2012

Blakemore, Robert J., 2012, On Schmarda’s lost earthworm and some newly found New Zealand species (Oligochaeta: Megadrilacea: Lumbricidae, Acanthodrilidae, Octochaetidae, & Megascolecidae s. stricto), Journal of Species Research 1 (2), pp. 105-132 : 118-121

Deinodrilus orcus sp. nov.

[ Fig. 11 ]

Material Examined. Holotype (H) AMNZ86029 (mature,

c b a a b c 1 mm sketched and dissected, in ethanol 80% and small tissue sample removed for DNA analysis, code WM4), Paratype (P), Te Papa W.002928 (mature that self-fragment- ed by autolysis into three bits induced by heat rather than handling; its anterior here dissected). Both specimens with same Mangamingi collection details as Rhododrilus mangamingi , but slightly deeper in scrub.

Etymology. After Roman god of the underworld and punisher of oath breakers (whence author J.R.R. Tokien partly derived the name for Orcs).

Diagnosis. Octochaetid with acanthodriline male and prostatic pores plus spermathecal pores in 7/8/9, all in b lines. Markings on 18 not pronounced. Gizzard in 6; calciferous glands lacking. Spermathecal diverticula four on each. mtDNA COI barcode as provided.

External characters. Anterior of the body circular. In life appears mottled white/red; preserved colour a delicate pastel pink-grey only slightly pigmented dorsally with faintly darker mid-dorsal line; clitellum paler buff. Length 88 mm with 150 segments (H); Paratype in three fragments that combined add up to 80 mm and ca. 144 segments. Prostomium epilobous faintly closed (H) or open (P). Setae perichaetine, 12 per segment, evenly spac- ed. Clitellum, annular, pale, tumid in 13-16 encroaching on adjacent segments slightly (H, P). Dorsal pores from 10/11 (H, P). Nephropores not found (meroic). Spermathecal pores in b lines in 7/8 and 8/9, small but gaping. Female pores on 14 mid-way between setae a on 13 and 14 in common field. Prostatic pores approximately in position of setae b on 17 and 19 conjoined by seminal grooves shortly transecting intersegments 17/18 and 18/ 19. Male pores within concave seminal grooves lateral to position of b setae on 18. Segments 17-19 are tumid and setae are obscured in raised rectangular rim of male field. Genital markings not pronounced, although segment 8 is puckered ventrally (due to copulation) and there are distinct circular papillae just median to b setae on 18 (H and P). Genital and penial setae not found.

Internal morphology. Cerebral ganglion in 2. Septa all thin except perhaps 10/11 and 11/12. Crop in 5 (it appears that weak septum 5/6 goes just below), strong muscular gizzard occupies 6-8 but seems actually in 6 (weak septum 6/7 can be carefully teased off past mid-point at least). Dorsal blood vessel doubled in 6-18, at least. Heart paired in 10-13 (in P, unclear in H). Nephridia meroic; large equatorial clusters from 4 at least centred approximately in c-d lines, smaller on and after clitellum. Spermathecae in 8 and 9 each with a long, thin duct to multiple, finger-like diverticula (inseminated with mostly four per spermatheca in H and P but 9 lhs in H has three and this plus some are bifid), surrounding duct from where it thickens before reaching yellowish, slightly dilated ampulla. Testes free, posterio-ventrally in 10 and 11. Seminal vesicles large, racemose anteriorly in 11 and 12 from septa 10/11 and 11/12. Ovaries flattened fan-shaped in 13 with several strings; no ovisacs seen in 14. Prostates tubular in 17 and 19 exiting through muscular ducts, no penial setae found. Oesophagus thin in 8 and 9, slightly dilated and vascularized in 10,11-15 but not construed as calciferous glands, with intestinal origin somewhat indeterminate but after 16 (this region mascerated in H). Intestinal typhlosole from around 19 (H and P) thin, lamellar becoming deeper further back. Intestine has masses of white ‘lipid’ sacs dorsally. Gut contains colloidal soil and organic matter (topsoil dweller/detritivore).

Ecology. Found in friable topsoil further into dense scrub than Rhododrilus mangamingi .

mtDNA results. megaBLAST highest max identity (95%) on GenBank is observed with D. gorgon Blakemore, 2010 which is here considered sufficient divergence for specificity.

Remarks. Of the ten currently known Deinodrilus species, D. orcus comes morphologically closest to D. agilis Lee, 1952 from Waiotapu that is located nearby. The main differences are its seminal groves and male pores in midab rather than in b-lines as here, it further has five pairs of calciferous glands in 9-13 and dorsal pores from 16/17. Similar species are D. montanus Lee, 1952 from Rimutaka Range en route to Featherstone, also D. gorgon Blakemore, 2010 and D. medusa Blakemore, 2010 from Happy Valley on the South Island that, however, all have genital markings on 10, at least. Despite Lee’s (1952b) description of these markings in D. montanus they are not shown in his plate 119 figure; but other differences are that dorsal pores are also given as from 16/17 and, furthermore, it lacks a typhlosole. In all these species, spermathecal diverticula number five except D. medusa that has four (or three) as here. Amongst other differing characteristics, D. medusa has seminal vesicles in 9-12. Molecular support for the current species is provided by its unique mtDNA COI barcode data in Appendix I.

Revival of genus Tokea Benham, 1904

Family MEGASCOLECIDAE s. stricto ( Blakemore, 2000c)

Genus Tokea Benham, 1904

A chequered history of the genus was summarized by Benham (1942: 224) like this:

“ As an illustration of this uncertainty, mention may be made of my genus Tokea (1905) [1904?]. In 1907 Michaelsen (p. 161) regarded this genus as really included in Megascolides . In 1916 (according to Stephenson (1923, p. 193, and 1930, p. 835), for I have not access to the original paper, Michaelsen includes it in the genus Notoscolex on the ground of the microscopic structure of the prostate. Again, in 1910, Michaelsen (p. 36), in discussing the geographical distribution of these and related genera, refers repeatedly to the occurrence of Megascolides in New Zealand and Ceylon, but in 1916 comes to the conclusion that New Zealand earthworms formerly attributed to Megascolides must be removed from that genus to Notoscolex . Consequently New Zealand must be excluded from the geographical distribution of Megascolides . And so my Tokea has been shifted about, first as a subgenus of Megascolides in 1907 (p. 161), and then to Notoscolex in 1916. Now when our greatest authority on the Oligochaeta (unfortunately deceased) is so uncertain as to the limitation of the two genera, refers repeatedly to the occurrence, it is not surprising that Stephenson (who is likewise defunct), and who was, as his Monograph reveals, the next authority on the group, but who had followed Michaelsen, should have presented two opinions as to Tokea , for in 1930, p. 658, he refers to the edibility of ‘ Tokea (Megascolides) ,’ while on p. 837 he wrote: ‘ Tokea must now go into Notoscolex .’ Confusion worse confounded! ”

Lee (1952: 26) concluded that Tokea belonged in Megascolides , explaining:

“ Benham (1904) established a genus, Tokea , for several species from the North Island of New Zealand which had all the characters of Megascolides , but differed from that genus in one respect. The prostate had a simple central canal, but when sections of the gland were examined, it was found that the gland cells were grouped into small clusters which discharged their secretion into a slight evagination of the central duct. Benham called these small evaginations of the central duct ‘canalicules’. It was unfortunate that he chose this term, since it really means a small canal and was taken as such by other workers, who placed Benham’s species in Notoscolex . However, reference to the figures in Miss Sweet’s paper on the structure of prostatic glands (1900), or to Benham’s paper (1941) on Megascolides napierensis , in which he figures a crosssection of the prostate of Megascolides (Tokea) esculenta and details of the ‘canalicules’, will show what Benham meant by the term. I have examined sections of the prostatic gland of other genera of the family Megascolecidae and have found that these ‘canalicules’ are present in the prostates of other genera which have tubular prostates, e.g. in Neodrilus they are present in large numbers.”

Benham (1904) did not explicitly select a type-species for his genus, however the exemplar he described first and in greater detail was Tokea esculenta , an edible native identified as “ kurekure ”: a food reserved for M-aori chiefs, and Michaelsen (1907: 161), if we accept he acted as ‘First Reviser’, seemingly accepted this as type-species. With no opportunity to inspect the type-specimen, Blakemore (2011) transferred it to genus Aporodrilus from Notoscolex where it had resided following my revisions in 1999 ( Blakemore, 2000 a) on the assumption that its prostates were tubuloracemose because, having missed Lee’s (1952) clarification above, I had taken Benham’s original characterization of “ tongue-shaped ” glands having “ canalicules ” to mean they were non-tubular. This action inadvertently made Aporodrilus a temporary junior synonym of prior Tokea , albeit the remainder of the genus was still mostly subsumed in Notoscolex . Referring to information from Benham and Lee quoted above clarifies that, since the prostates actually qualify as tubular, Tokea indeed complies with Megascolides . However, lack of dorsal pores in the type, T. esculenta , gives precedent for restoration of the genus on the basis of this feature that, as it similarly separates Aporodrilus from Notoscolex (both with non-tubular prostates), now separates Tokea from Megascolides (both with tubular prostates).

In the appended checklist (Appendix II), those NZ species formerly qualifying for Tokea are restored having key characteristics of: lumbricine setae, avesiculate meroic nephridia, tubular prostates and being shown (or presumed) to lack dorsal pores. Tokea maorica Benham, 1904 (at least) has dorsal pores and is therefore returned as Megascolides maoricus (Benham, 1904) , whilst Megascolides parvus Lee, 1952 lacks them so is newly transferr- ed as Tokea parva (Lee, 1952) .

Summary knowledge of M. orthostichon

Figures

Fig. 11. Deinodrilus orcus Blakemore, sp. nov. Holotype AMNZ86029 showing dorsal view of prostomium and ventral aspect of body with spermathecae in 8 rhs & 9 rhs and prostates in 17 rhs & 19 rhs in situ. [Paratype setal ratios of 12 rhs boxed].