Cervidellus hueckeswagensis, Mach & Pettrich & Villegas & Waldvogel & Schiffer & Holovachov, 2025

Mach, Niclas, Pettrich, Laura, Villegas, Laura, Waldvogel, Ann-Marie, Schiffer, Philipp H. & Holovachov, Oleksandr, 2025, Description of Cervidellus hueckeswagensis sp. nov. and Stegelleta waltrautae sp. nov. (Nematoda: Rhabditida: Cephalobidae) from the Atacama Desert in Chile, European Journal of Taxonomy 1012, pp. 222-238 : 223-227

Cervidellus hueckeswagensis sp. nov.

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Figs 1–3 , 7A–F , Tables 1–2

Diagnosis

Cervidellus hueckeswagensis sp. nov. is characterized by a body length of 488–539 µm in females; cuticle with longitudinal incisures; lateral alae with five incisures extending to tail tip; three pairs of asymmetrical lips, pairs of lips separated by V-shaped primary axils with two triangular-acute guarding processes, and each lip asymmetrically triangular with 6–7 tines along its margin; three labial probolae, each bifurcated at one level, at about half of their length; labial probolae lacking additional tines or swellings; pharyngeal corpus 2.1–3.4× as long as isthmus; excretory pore at corpus/isthmus level; vulva continuous with body contour; spermatheca 7–15 µm long; and post-vulval uterine sac 12–32 µm long.

Etymology

The specific epithet is derived from the hometown (‘Hückeswagen’) of the first author.

Type material

Holotype

CHILE • ♀; Tarapacá Region, Tamarugal Province ; 20°34.883′ S, 68°46.517′ W; 4056 m a.s.l.; 4 Oct. 2022; O. Holovachov, L. Villegas, L. Pettrich, A.-M. Waldvogel and P. Schiffer leg.; soil, sample code ALT.22.10 ( Fig. 7A–B ); SMNH Type-9945; SMNH.

Paratypes

CHILE • 6 ♀♀; same data as for holotype; SMNH Type-9945; SMNH .

Other material examined

CHILE • 7 ♀♀; Tarapacá Region, Tamarugal Province ; 20°20.383′ S, 68°58.517′ W; 4196 m a.s.l.; 3 Oct. 2022; O. Holovachov, L. Villegas, L. Pettrich, A.-M. Waldvogel and P. Schiffer leg.; soil under Azorella compacta Phil. , sample code ALT.22.08 ( Fig. 7E–F ); SMNH .

Associated molecular data

CHILE • 1 ♀; Tarapacá Region, Tamarugal Province ; 20°20.150′ S, 69°02.567′ W; 3886 m a.s.l.; 3 Oct. 2022; O. Holovachov, L. Villegas, L. Pettrich, A.-M. Waldvogel and P. Schiffer leg.; soil under unidentified bush, sample code ALT.22.04; GenBank no: PQ587598 (18S) • 1 ♀; Antofagasta Region, El Loa Province ; 23°30.967′ S, 67°50.933′ W; 3830 m a.s.l.; 9 Oct. 2022; Holovachov, A.-M. Waldvogel, L. Schiffer and P. Schiffer leg.; soil under dead cactus, sample code EPT.22.3830; GenBank no: PQ587809 .

Description

Adult

Body variably curved ventrad upon fixation (fixed without applying heat). Cuticle coarsely annulated, annuli 2–2.5 µm wide at midbody. Longitudinal incisures present, giving cuticle tiled appearance. Lateral alae start at level of procorpus, and expand to five incisures at metacorpus / ithmus, extending to tail tip. Lip region slightly offset, with six labial and four cephalic papillae. Amphid opening relatively small, oval, located at base of each lateral lip. Three pairs of asymmetrical lips, one dorsal and two ventrolateral. Pairs of lips separated by V-shaped primary axils with two triangular-acute guarding processes. Secondary axils V-shaped, without guarding processes. Each lip asymmetrically triangular with 6–7 elongate-triangular tines along its margin: 2–3 tines facing primary axil, one long tine pointing forward, and three long tines facing secondary axil ( Fig. 3 ). Three labial probolae bifurcated at about half of their length; prongs slender, curved towards each other, without secondary tines or bifurcations. Basal knobs or ridges absent. Stoma about as long as lip region diameter. Cheilorhabdia irregular in latero-median view; metastegostom with large dorsal denticle. Pharynx cephaloboid. Pharyngeal corpus fusiform; isthmus well demarcated from corpus; basal bulb oval with well-developed grinder. Nerve ring surrounding metacorpus but poorly visible in most specimens. Excretory pore at level of corpus-isthmus junction. Deirids at level with isthmus or basal bulb.

Female

Reproductive system monodelphic, prodelphic, in dextral position relative to intestine. Ovary reflexed posteriorly at oviduct, straight posterior to vulva. Vulva continuouing with body contour. Spermatheca weakly developed, often hard to recognize. Post-vulval uterine sac usually small, equal to one vulval body diameter. Tail conoid with 14–16 ventral annuli, and terminus minutely rounded. Phasmids located at about 30–56% of tail length.

Male

Not found. Species is possibly asexual.

Differential diagnosis

Cervidellus hueckeswagensis sp. nov. from Chile is most similar to C. caucetensis Holovachov, Boström & De Ley, 2011 and C. vinciguerrae Clausi, 1998 in the shape of the labial probolae (bifurcated at about middle of their length and with slender, curved inwardly prongs slender, without secondary tines or bifurcations), and to C. bifidihastatus Abolafia & Robles, 2024 , C. hamatus Thorne, 1937 , C. doorsselaeri (De Clerk & De Ley, 1990) Boström & De Ley 1996 and C. capraeolus (De Ley, Geraert & Coomans, 1990) Boström & De Ley 1996 in the shape of the cephalic probolae (asymmetrically triangular with multiple tines), see Table 2 for more details.

The new species differs from C. caucetensis in the shape of cephalic probolae and larger number of tines (6–7 vs 4) the mode of reproduction (asexual vs sexual) and the length of the spermatheca (7–15 µm vs 24–35 µm); C. vinciguerrae in the shape of the cephalic probolae and the larger number of tines (6–7 vs 5), the mode of reproduction (asexual vs sexual) and the length of the spermatheca (7–15 µm vs 27–40 µm); C. bifidihastatus in the shape of the labial probolae (without vs with backwardly directed spur-like processes), a different number and shape of tines on the cephalic probolae (two-three tines facing the primary axil, one long tine pointing forward, and three long tines facing the secondary axil vs four small rounded tines facing the primary axil, one rounded tine facing forward, and three larger rounded tines facing the secondary axil), the mode of reproduction (asexual vs sexual) and the length of the spermatheca (7–15 µm vs 16–19 µm); C. hamatus in the shape of the labial probolae (without vs with bifurcation), a different number and shape of tines on the cephalic probolae (2–3 tines facing the primary axil, one long tine pointing forward, and three long tines facing the secondary axil vs three small tines facing the primary axil, no tine pointing forward and three large tines facing the secondary axil) and the length of the spermatheca (7–15 µm vs 16–37 µm); C. doorsselaeri in the shape of the labial probolae (without vs with bifurcation) and a different number and shape of tines on the cephalic probolae (two-three tines facing the primary axil, one long tine pointing forward, and three long tines facing the secondary axil vs two round tines facing the primary axil, three tines pointing forward and one rounded and two acute tines facing the secondary axil); C. capraeolus in the shape of labial probolae (without vs with bifurcation and additional processes), different number and shape of tines on the cephalic probolae (2–3 tines facing the primary axil, one long tine pointing forward, and three long tines facing the secondary axil vs two round tines facing the primary axil, two tines pointing forward and four tines facing the secondary axil) and the length of the post-vulval uterine sac (12–32 µm vs 4–6 µm).

Figures

Fig. 1. Cervidellus hueckeswagensis sp. nov. A–D. Holotype, ♀ (SMNH Type-9945). A. Pharyngeal region. B. Tail. C. Reproductive system. D. Entire female. E–G. Schematic illustration of the details of the head region, combined based on several individual nematodes. E. Anterior end, surface view. F. Cephalic probolae. G. Labial probola.

Fig. 2. Cervidellus hueckeswagensis sp. nov. A. Holotype, ♀ (SMNH Type-9945), anterior pharyngeal region. B–L. Female paratypes (SMNH Type-9945). B, J. Post-vulval uterine sac (arrows). C, F. Caudal region. D. Oocytes in uterus. E, K. Vulva and post-vulval uterine sac (arrows). G–H, L. Spermatheca (arrows). I. Posterior pharyngeal region (arrow points at excretory canal). Scale bars = 10 μm.

Fig. 3. Cervidellus hueckeswagensis sp. nov., female paratypes (SMNH Type-9945). A–E. Anterior end, lateral view, right side (arrow shows amphid). F. Anterior end, lateral view, left side. Scale bars = 10 μm.

Fig. 7. Habitats. A–F. Sampling sites of Cervidellus hueckeswagensis sp. nov. A–B. ALT.22.0. C–D. EPT.22.3830. E–F. ALT.22.08. G–H. Sampling site of Stegelleta waltrautae sp. nov., TDT.23.14.