Desmodorella verscheldei, Leduc & Zhao, 2016

Leduc, Daniel & Zhao, Zeng, 2016, Phylogenetic relationships within the superfamily Desmodoroidea (Nematoda: Desmodorida), with descriptions of two new and one known species, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 176 (3), pp. 511-536 : 514-517

publication ID	https://doi.org/ 10.1111/zoj.12324
publication LSID	lsid:zoobank.org:pub:175CF665-173D-40DE-AA2F-8417F520AE22
persistent identifier	https://treatment.plazi.org/id/6F5DD678-E0B0-4128-8A31-E961B1677AED
taxon LSID	lsid:zoobank.org:act:6F5DD678-E0B0-4128-8A31-E961B1677AED
treatment provided by	Marcus
scientific name	Desmodorella verscheldei
status	sp. nov.

Treatment

DESMODORELLA VERSCHELDEI SP. NOV.

( TABLE 1, FIGS 1–4 View Figure 1 View Figure 2 View Figure 3 View Figure 4 )

Type specimens

Holotype male ( NIWA 88383 View Materials ), collected on 12.i.2015, Hataitai Beach , Wellington, New Zealand (41° 18′ 22″ °S, 174° 47′ 58″ °E), intertidal coarse sand and gravel sediments. One male and three female paratypes, same data as holotype ( NIWA 88384 View Materials , NNCNZ 3194 , 3195 ).

Etymology

The species is named after Dominick Verschelde (Ghent University, Belgium), for his contribution to the taxonomy of the Desmodoridae .

Description

Males: Body cylindrical with orange-brown coloration, narrowest in region between pharynx and anterior extremity of testis and widest at mid-level of testis. Cuticle coarsely annulated; annules in anterior *At level of amphid. a, body length/maximum body diameter; abd, anal body diameter; b, body length/pharynx length; c, body length/tail length; cbd, corresponding body diameter; diam., diameter; L, total body length; Max., maximum; V, vulva distance from anterior end of body; % V, V /total body length.

pharyngeal region more widely spaced than elsewhere (ten annulations per 12–18 μm vs. ten annulations per 28–31 μm, respectively). Anterior-most ten to 15 annules ornamented with short, stout pointed projections facing anteriorly, not arranged in longitudinal rows (not to be confused with long thin spines arranged in longitudinal rows typical of the genus further along body), each with one thin, hair-like spine at base, 5–8 μm long ( Figs 3C View Figure 3 , 4A View Figure 4 ); subsequent annules ornamented with at least 20 longitudinal rows of thin spines in pharyngeal region, merging into 16–20 rows on main body. The two lateral pairs of longitudinal spines are closer to each other and comprise slightly larger spines ( Fig. 3D View Figure 3 ). Short somatic setae arranged in eight longitudinal rows.

Long, well-developed head capsule with separate, retractable lip region ( Figs 3B View Figure 3 , 4B View Figure 4 ). Six inner labial setae and six outer labial setae of similar length situated on lip region, 1–3 μm long; four longer cephalic setae situated slightly posterior to lip region and at level of anterior edge of amphids, 0.17–0.19 cbd ( Fig. 3B View Figure 3 ). Eight subcephalic setae (four pairs) on head capsule; two subdorsal and two subventral subcephalic setae near mid-level of amphid, and two ventrosublateral and two dorsosublateral subcephalic setae situated at base (posterior level) of the amphids and further posteriorly at base of head capsule ( Fig. 4B View Figure 4 ). Amphideal aperture and amphideal fovea both loop-shaped and spanning almost entire length of head capsule; amphideal aperture is however conspicuously thinner than amphideal fovea and is reduced to narrow slit except at posterior tip ( Figs 3C View Figure 3 , 4B View Figure 4 ). Buccal cavity with large cuticularized dorsal tooth and two smaller subventral teeth. Pharynx cylindrical, slightly swollen around buccal cavity and with small oval to pyriform posterior bulb. Cardia small. Secretory–excretory system and nerve ring not observed.

Reproductive system monorchic with outstretched testis located to right of intestine. Mature sperm globular, nucleated, 4–6 × 5–8 μm. Thin, extremely long spicules, 10–14 abd, with slightly swollen proximal end and pointed distal end. Small gubernaculum with slight lateral crurae; gubernacular apophyses absent. Precloacal supplements or setae not observed. Tail short, conical, with non-annulated posterior end and with three caudal glands reaching to level of gubernaculum.

Females: Similar to males; one specimen with additional subcephalic setae situated dorsosublaterally and subventrally (ten in total; Fig. 2A View Figure 2 ). Reproductive system didelphic, amphidelphic with reflected ovaries situat- ed both ventrally, both to the left of intestine, or one on left and other on right of intestine. Vulva located near two thirds of body length from anterior extremity. Cuticular pars distalis vaginae and pars proximalis vaginae surrounded by constrictor muscle. Two groups of small vaginal glands present. Caudal glands extend ∼ 1 abd anterior to anus.

Diagnosis

Desmodorella verscheldei sp. nov. is characterized by the presence of stout pointed projections with hair- like spines at their base on the anterior-most ten to 15 body annules, cuticle with two pairs of longitudinal rows of larger spines, head capsule with large loopshaped amphids and eight subcephalic setae, and males with spicules 10–14 abd long.

Differential diagnosis

Desmodorella verscheldei sp. nov. can easily be differentiated from all other species of the genus by the loopshaped amphids; all other species are characterized by multispiral amphids with ≥ 1.25 turns ( Verschelde et al., 1998), or by unispiral amphids ( Desmodorella aquaedulcis ). Loop-shaped amphids are rare within the Desmodoridae , but have also been found in males of Psammonema ovisetosum Verschelde & Vincx, 1994 , Pseudochromadora galeata Verschelde et al., 2006 , and Desmodora porosum Moura et al., 2014 . The new species also differs from all other species of the genus by the presence of pointed projections bearing thin spines on the anterior-most ten to 15 body annules. The presence of two pairs of longitudinal rows of larger spines was also observed in Desmodorella balteata . Very long and thin spicules such as those observed in Desmodorella verscheldei sp. nov. are present in four other species of the genus: Desmodorella filispiculum , Desmodorella sanguinea , Desmodorella sinuata , and Desmodorella spineacaudata .

This study provides the first molecular sequences for the genus Desmodorella . Based on SSU molecular sequences, Desmodorella verscheldei sp. nov. differs from Desmodora marci ( JX463180 View Materials ) by 5% (77 in 1662 bp including 11 gaps) and Desmodora sp. ( JX463181 View Materials ) by 6% (42 in 702 bp including one gap) ( Fig. 14 View Figure 14 ).