Rhododrilus mangamingi, 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 : 116-118

Rhododrilus mangamingi sp. nov.

[ Fig. 10 ]

Material Examined. Holotype (H) AMNZ86028 (mature, sketched, dissected). From fenced remnant scrubland above and to NE of Te Kopia geothermal field features on sheep paddock at Mangamingi Station (ca. S38̊ 5.535 E 176̊12.996; Atiamuri region NZTM E1880782 N5742 165 AMSL 630 m pg. 223 of www.waikatoregion.govt. nz/PageFiles/20544/1.6TeKopia.pdf that provides ecological and vegetative data). Collected by RJB 28 th Nov., 2011. Fixed in 80% ethanol and small tissue sample removed for DNA analysis (WM5).

Etymology. After type locality.

Diagnosis. Acanthodrilid with microscolecine reduction of male and prostatic pores to 17. Penial setae present. Muscular gizzard in 5. Spermathecal pores near b lines in 7/8/9. Markings on 19. Holoic nephridia avesiculate. mtDNA COI barcode as provided.

External characters. Body circular. Pale unpigmented; clitellum buff. Length 60 mm with 100 segments (broken in half during dissection). Prostomium epilobous. Setae lumbricine, evenly spaced. Clitellum annular, 13- 16. Neither dorsal pores nor nephropores found; however there are a few small mid-dorsal dots present after clitellum and minute perforations were detected in c lines in excised cuticle. Spermathecal pores near b lines in 7/8 and 8/9. Female pores on 14 above setae a. Male and prostatic pores combined at ab on 17; ab setae replaced with penial setae. Genital markings as faint indistinct pads in 19 posterior to ab setae (no glands internally). Setae ab in 18 and 19 appear unmodified.

Internal morphology. Septa all thin. Gizzard large in 5. Dorsal blood vessel single. The last pair of hearts detect- ed in 12. Nephridia holoic, avesiculate in c lines throughout. Spermathecae in 8 and 9 each a spherical ampulla on short duct with a thumb-like diverticulum. Testes flat and iridescent in 10 and 11. Seminal vesicles large, racemose posteriorly in 9 and anteriorly in 11 and 12. Small pseudo-vesicles on posterior of 12/13 and 13/14. Ovaries in 13 with several egg strings. Prostates tubular in 17 with a flaccid duct and long penial setae. Oesophagus not noticeably modified, with intestinal origin somewhat indeterminate after 16 (possibly in 17). Intestinal typhlosole absent. Gut contains fine soil (selective topsoil dweller rather than detritivore).

Ecology. Dug from loose soil under scrub near paddock fenceline with Lumbricus rubellus , L. terrestris (specimens not kept) and with Deinodrilus orcus sp. nov. nearby.

mtDNA results. megaBLAST match no closer than 84% max identity with various worms, i.e., nothing similar yet sequenced on GenBank.

Remarks. Rhododrilus is one of the larger genera with 30 New Zealand members ( Lee, 1952a; 1959; 1962). The present species lacks dorsal pores (not mentioned by Lee) and has minute nephropores presumed to exit in setal c lines where avesiculate nephridia attach. Vesiculate Rhododrilus benhami Lee, 1952 is superficially similar with faint markings in 19, but it has a tanylobous prostomium and spermathecal pores in setal a lines. Especially similar avesiculate species are Rhododrilus aquaticus Lee, 1959 from Caswell Sound in the SW Fiordland that is smaller (30-40 mm) with male pores at the end of a transverse ridge, amongst other differences, or R. cockaynei Benham, 1905 from Auckland, Campbell and Snares Islands that has a saddle-shaped clitellum and spermathecal pores at anterior margins of 8 and 9 (or 7, 8 and 9). Species with spermathecal pores in 7/8/9 and annular clitella in 13-16,17 are R. huttoni (Benham, 1901) and R. dobsoni Lee, 1959 that also lack nephridial vesicles but both have prostatic pores in setal a lines; while vesiculate R. microgaster Lee, 1959 and R. papaensis Lee, 1952 additionally have reproductive pores that are mid-ventral or in ab lines, respectively. All four latter species also have different seminal vesicle arrangements.

The long, thin penial setae of the current species are distinctive, but their minutae are purposefully omitted for reasons cogently explained by Blakemore (2002; 2010a; 2010b), viz.: the microscopic details reported for these are of debatable value for some such taxa as they vary individually, even within a bundle, are damaged or worn by age and use, and may be similar if not the same in several species. For example, Lee (1962: 170) found details of penial setae of Rhododrilus minutus Beddard, 1889 to differ intraspecifically. And, as Gates (1972: 23) observed: “ The systematic importance claimed for differences of shape, sculpturing, and ornamentation in those kinds of setae in the classical system, may have been too great. Penial setae may show considerable intraspecific variation or may be similar if not the same in several species.”

Moreover, even when present, the reliance on penial setal detail for specific characterization requires these be

20 1 mm

elucidated for all specimens under consideration (which is not always the case), and is impracticable for the majority of field workers who lack access to high-powered or scanning electrode microscopes ( SEM) or for taxonomists pressed for time. Finally, their importance to determine specific affinities is rendered irrelevant when replaced by compelling DNA data (preferably from types), as used here .

Family OCTOCHAETIDAE Michaelsen, 1900 sensu Blakemore, 2000

Genus Deinodrilus Beddard, 1889

Figures

Fig. 10. Rhododrilus mangamingi Blakemore, sp. nov. Holotype AMNZ86028 showing dorsal views of prostomium (pharynx everted) and pygidium; ventral aspect of body with gizzard, spermathecae in 8 rhs & 9 rhs and prostate in 17 lhs with penial setae in situ, plus actual setal ratios in 9 rhs.