Nicolenella isabelleana Perina & Camacho, 2025

Perina, Giulia, Camacho, Ana I., Morgan, Liesel, Floeckner, Stephanie & Guzik, Michelle T., 2025, Morphological and molecular description of ten new species of a new genus of Parabathynellidae (Bathynellacea, Crustacea) from the Pilbara region, Western Australia, Zootaxa 5712 (1), pp. 1-103 : 61-66

publication ID	https://doi.org/10.11646/zootaxa.5712.1.1
publication LSID	lsid:zoobank.org:pub:DE340A2B-AF2B-44E5-9C84-63A0D422AE8B
DOI	https://doi.org/10.5281/zenodo.17885080
persistent identifier	https://treatment.plazi.org/id/310187A9-5607-FF8F-FF79-0EBEFE953645
treatment provided by	Plazi
scientific name	Nicolenella isabelleana Perina & Camacho
status	sp. nov.

Treatment

Nicolenella isabelleana Perina & Camacho , sp. nov.

( Figs. 21–23 View FIGURE 21 View FIGURE 22 View FIGURE 23 , Appendix 7H)

urn:lsid:zoobank.org:act:

Material examined. Holotype male. AUSTRALIA: Western Australia: Gudai Darri, Pilbara , Bore MR 05 KDDWB001 ( stygo net haul), 22°19'49.8864"S, 118°39'41.4576"E, 21 September 2021, F. Rudin, P. Runham ( WAMC 82055 - BMR05147 View Materials - BES13219 A, permanent slide). GoogleMaps

Paratypes: AUSTRALIA: Western Australia: 1 female, WAM C79102 About WAM - BMR05145 View Materials - BES17476 B, permanent slide, same details as holotype, but collection date 20 October 2022, F. Rudin, A. Umbrello. 1 female, WAM C79103 About WAM - BMR03367 View Materials - BES8245 , permanent slide, same details as holotype, but collection date 1 November 2020, F. Rudin, M. Curran. 1 specimen (sex not available), WAM C79104 About WAM - BMR05974 View Materials - BES15836 , in ethanol, same details as holotype. 1 male, WAM C82053 About WAM - BMR05144 View Materials - BES17476 A, in ethanol, same details as WAMC 79102 . 1 female, WAMC 82054 - BMR05146 View Materials - BES8110 permanent slide, same details as holotype, but collection date 19 July 2022, P. Runham, I. Johansson. 1 male, WAMC 82056 - BES13219 , permanent slide, same details as holotype.

Additional material: 2 males and 2 females, WAMC 82057 - BES13219 , in ethanol, same details as holotype .

Diagnosis. AI seven-segmented. AII five-segmented. Mandibular palp one-segmented formed by one long article and one seta that does not extend beyond the distal end of the pars incisiva. Distal endite of maxillula with five claws. Three or four articles on exopod of thoracopods. One internal seta on first article of endopod of ThII to VII. Male thoracopod VIII sub-rectangular, about 1.5 times as long as wide. Sympod of the uropod with homonomous spines; exopod of the uropod similar in length to endopod, with two distal setae. Furca with few small inner spines and two strong distal ones. It differs from all other species of Nicolenella gen. nov. by the combination of characters listed in Supplementary Material TableS2. The sequenced specimens differ from all the other Nicolenella gen. nov., Billibathynella and Brevisomabathynella species sequenced by COI = 16.6–24.3% and 12S = 20.2–30% ( Table 3, Appendix 2, 3).

Description male holotype (WAMC 82055). Body length of 1.05 mm. Body nearly five times as long as maximum width elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body (Appendix 7H).

Antennula ( Fig. 21A View FIGURE 21 ): seven-segmented, nearly two times longer than AII. The first article is the longest, followed by the second and the third articles, which are similar in length, sixth and seventh articles similar in length and slightly longer than the fourth and fifth ones which are the shortest. Sixth and seventh articles with three terminal aesthetascs. Antennular setation as in Fig. 21A View FIGURE 21 .

Antenna ( Fig. 21B View FIGURE 21 ): five-segmented; less than half the length of AI; the first two articles are similar in length and very short; third is double the length of the first, fourth and fifth articles similar in length, and about twice the length of the third article. Setal formula of AII: 0+0/0+0/1+1/1+1/3(1).

Labrum ( Fig. 21C View FIGURE 21 ): flat, free edge with 15 teeth.

Paragnaths: absent.

Mandible ( Fig. 21D View FIGURE 21 ): pars incisiva with four teeth; pars molaris with nine claws, the seven distal ones denticulated, and the two most proximal ones joined together; tooth of ventral edge triangular. Mandibular palp with one long article and seta not reaching the distal end of the pars incisiva.

Maxillula ( Fig. 21E View FIGURE 21 ): proximal endite with four almost equal claws; distal endite with five claws: three apical and one proximal smooth and one denticulated; two smooth, unequal subterminal setae on the outer distal margin.

Maxilla ( Fig. 21F View FIGURE 21 ): four-segmented, setal formula 2, 3,8,7.

Thoracopods I to VII ( Figs. 22A–E View FIGURE 22 , 23A,B View FIGURE 23 ): length slightly increasing from thoracopod one to four, and similar in length from ThV to VII. Epipod present in all thoracopods, about half of the length of the corresponding basipod. All basipods with one distolateral seta longer than the first article of the endopod in ThI and II, shorter in ThIII to VII. Exopod same length as endopod in ThI, II and VI , longer in ThIII to V, and slightly shorter in ThVII. Exopod of all thoracopods with two very long distal setae on each article. Number of exopodal segments of ThI to VII: 3-3- 3/4-4-4-4-4. Endopod four-segmented in all thoracopods. First article shorter than article two and three, which are similar in length, and the fourth article small in all thoracopods; first and second articles bearing an outer plumose seta and one smooth inner seta in all thoracopods, except ThVI that has no inner seta on the first article; third article with one outer distal seta on all thoracopods; fourth article very reduced with two strong claws of different length and one smooth seta on all thoracopods. Setal formula of endopods as follow:

ThI to V and VII 1+1/2+1/0+1/3(1)

ThVI 0+1/1+1/0+1/3(1)

Thoracopod VIII ( Fig. 23D,E View FIGURE 23 ): compact, longer than wider. Penial region with massive protopod. Outer lobe elongated, finger-like, reaching beyond the distal end of basipod, and not defined at base. Dentate lobe with several distal teeth. Inner lobe oval and as long as outer lobe. Basipod without setae, but with a frontal denticulated crest (or projection). Endopod small, similar to exopod, with one long seta.

Pleopod I ( Fig. 23C View FIGURE 23 ): one segmented with a long smooth seta.

Uropod ( Fig. 22F View FIGURE 22 ): sympod more than twice as long as the endopod, and nearly four times as long as wide, with eight homonomous spines occupying about half of the length of the sympod. Endopod similar in length to exopod, with two distal strong spines and one inner small one, two dorsal plumose setae that exceed the tip of the distal spines and two long distal barbed setae. Exopod with five barbed setae, two terminal, two dorsal, and one basiventral seta.

Pleotelson ( Fig. 22G View FIGURE 22 ): with one very short lateral seta on each side; anal operculum not protruded.

Furca ( Fig. 22G View FIGURE 22 ): rami trapezoidal, with eight barbed spines, six short proximal ones and two strong and longer distal ones. Two dorsal plumose setae, the inner one short and the outer one reaches beyond the end of the distal spines.

Female paratype differs from male in the small cone-shape thoracopod VIII ( Fig. 23F,G View FIGURE 23 ).

Variability: variability was observed in body size (male 1.05–1.21 and female 1.03–1,08 mm), number of teeth on labrum (14–16); number of claws on pars molaris (7–9), number of exopodal articles on the thoracopods (3–4); number of inner setae on the first and second article of thoracopod endopods, number of spines on sympond of uropod (6–8), number of spines on endopod of uropod (3–4), number of setae on exopod of uropod (4–5)\, and number of spines on furcal rami (7–8).

Distribution and remarks. N. isabelleana sp. nov. has been collected in one bore in the middle of the Fortescue River Catchment ( Fig. 6 View FIGURE 6 ). This species was previously known by Biologic Environmental Surveys as Parabathynellidae sp. “Biologic-PBAT021”. N. isabelleana sp. nov. can be distinguished by the combination of characters listed in Supplementary Material Table S2. It is part of a well-supported clade formed by Parabathynellidae sp. PBAT038 ( N. sp. PBAT038) collected about 80 km southeast of N. isabelleana sp. nov. type locality, and N. pilbaraensis comb. nov. ( Fig. 2 View FIGURE 2 ) collected in the Ethel Gorge, about 150 km southeast ( Fig. 6 View FIGURE 6 ).