European journal of taxonomy : EJT
Paris : Muséum National d'Histoire Naturelle
ISSN: 2118-9773
Refine
Year of publication
- 2015 (2) (remove)
Document Type
Language
- English (2)
Has Fulltext
- yes (2)
Is part of the Bibliography
- no (2)
Keywords
- Chatham Rise (1)
- Desmodoridae (1)
- Linhomoeidae (1)
- Monhysteridae (1)
- New Zealand (1)
- Sphaerolaimidae (1)
- deep-sea (1)
- hadal (1)
- meiofauna (1)
- southern Hikurangi Margin (1)
158
Three new species of the order Monhysterida are described based on specimens obtained at depths of 8081 and 9177 m in the Kermadec Trench. Thelonema clarki sp. nov. is characterised by a large body size (3230–4461 μm), short cylindrical buccal cavity, gubernaculum without apophyses, and long conico-cylindrical tail. This is the first record of the genus since its original description over two decades ago from the Peru Basin. Metasphaerolaimus constrictus sp. nov. is characterised by a relatively long body (1232–1623 μm), slightly arcuate spicules without gubernaculum, and conico-cylindrical tail with inner cuticle conspicuously thickened immediately anterior to cylindrical portion. Monhystrella kermadecensis sp. nov. is characterised by a circle of papillose outer labial sensillae slightly anterior to the four short cephalic setae, gubernaculum with caudal apophyses, the presence of distinct cuticularised piece along anterior vaginal wall, and a relatively short conical (males) or conico-cylindrical tail (females) with conical, ventrally-curved spinneret. M. kermadecensis sp. nov. can be differentiated from all other species of the genus, and, indeed, the entire family, based on the variable position of the anterior gonad relative to the intestine. The new species is classified within the Monhysteridae, and not the closely-related Xyalidae, based on the small body size, a smooth cuticle, and the presence of six outer labial papillae and only one testis. Further work is required to clarify the placement of M. kermadecensis sp. nov. relative to other monhysterid genera. A tabular key to all ten valid Metasphaerolaimus species is presented.
118
Two new species of the family Desmodoridae are described from the upper continental slope of New Zealand, Southwest Pacific, and the genera Spirinia, Chromaspirina and Perspiria are revised. Spirinia verecunda sp. nov. is characterised by a short, stout body, cuticle covered in minute, hair-like structures, unispiral amphideal aperture and cryptospiral amphideal fovea, buccal cavity with small dorsal tooth and minute subventral teeth, eight oblong glands surrounding anterior portion of pharynx, large sperm cells, spicules with weak capitulum, and the absence of precloacal supplements. Stygodesmodora confusa sp. nov. is characterised by a relatively short body, spiral amphids with 1.2– 1.4 turns, cephalic setae situated at or slightly posterior to mid-level of amphid, and males with four precloacal supplements consisting of short setae on wide bases. Like other species of the genus, S. confusa sp. nov. is characterised by an annulated head region, but in some specimens the cuticle annulations are restricted to the dorsal and ventral sides of the head. S. confusa sp. nov. shows similarities with species of other desmodorid genera (i.e., Echinodesmodora, Bolbonema), but can be differentiated from them by the presence of an annulated head region and amphideal plates. The genera Spirinia, Chromaspirina and Perspiria have very similar morphologies and differ mainly in the size and structure of the buccal cavity (Spirinia vs Chromaspirina) or the shape of the tail and placement of the amphids relative to the cuticle annulations (Spirinia vs Perspiria); their diagnoses are clarified and some nomenclatural changes are proposed to eliminate overlap in the definitions of these genera.