Nicolenella vanweesae 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 : 50-54

Nicolenella vanweesae Perina & Camacho , sp. nov.

( Figs. 14–16 , Appendix 7E)

urn:lsid:zoobank.org:act:

Material examined. Holotype male. AUSTRALIA: Western Australia: Brockman, Pilbara , bore GR19BS3X0047 ( stygo net haul), 22°31'45.0735"S, 117°25'30.1994"E, 23 February 2021, J. Huey, S. Rodman ( WAMC 79079 - BES10271 c-BMR02587, permanent slide).

Paratypes AUSTRALIA: Western Australia: 1 female, ( WAMC 79077 - BES10271 a-BMR02585, permanent slide) , 1 female, ( WAMC 79078 - BES10271 b-BMR02586, in ethanol), and 1 male ( WAMC 79080 - BES10271 dBMR02588, in ethanol) same details as holotype ; 1 male, bore MB19 BS3X0001 ( stygo net haul), 22°32'19.4220"S, 117°25'27.2716"E, 19 October 2020, S. Rodman, M. van Wees ( WAMC 79081 - BES8362 b-BMR02296, permanent slide) ; 1 female ( WAMC 79082 - BES8362 c-BMR02297, permanent slide) same details as WAMC 79081 .

Additional material. AUSTRALIA: Western Australia: 1 juvenile, bore MB19 BS3X0002, ( stygo net haul), 22°31'56.7217"S, 117°25'42.3851"E, 22 February 2021, J. Huey, S. Rodman ( WAMC79083 - BES11198 - BMR02464 , in ethanol) , 1 specimen (sex not available), bore MB19 BS3X0002, 19 October 2020, S. Rodman, M. van Wees ( WAMC 79084 - BES8093 - BMR02286 , in ethanol) , 1 juvenile, bore RC19BS3X0337 ( stygo net haul), 22°31'49.8274"S, 117°25'35.1412"E, 22 February 2022, J. Huey, S. Rodman ( WAMC 79085 - BES10747 - BMR02465 , in ethanol) .

Diagnosis. AI seven-segmented with all articles similar in length, except article one. AII six-segmented, less than half of the length of AI. 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 six claws. Two to four articles on exopod of thoracopods. Male thoracopod VIII rectangular, one and about 1.5 times as long as wide. Sympod of the uropod with non-homonomous spines, with a different combination of slightly longer spines (for example, one to three distal spines can be longer than others, or the proximal spine can be shorter, (see photos in Appendix 8). Exopod and endopod similar in length; exopod without basiventral seta. Furca with few smaller inner spines and two distal ones twice as long as the rest. It differs from all other species of Nicolenella gen. nov. by the combination of characters listed in Supplementary Material Table S2. The sequenced specimens differ from all the other Nicolenella gen. nov., Billibathynella and Brevisomabathynella species sequenced by COI = 12.1–24.8% and 12S = 5–32% ( Table 3, Appendix 2,3).

Description male holotype (WAMC 79079). Body length of 1.13 mm. Body six times as long as maximum width, elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body (Appendix 7E).

Antennula ( Fig. 14A ): seven-segmented, over two times longer than AII. The first article is the longest, the second, third and seventh are similar in length, the fourth and fifth are similar in length and slightly shorter than the sixth article. Inner flagellum small and trapezoidal. Article five with two and article six and seven with three terminal aesthetascs. Antennular setation as in Fig. 14A .

Antenna ( Fig. 14B ): six-segmented; first two articles very small and similar in length; third article slightly longer than the first two; fourth and fifth articles slightly longer than article three, and article six is the longest. Setal formula of AII: 0+0/0+0/1+1/1+1/0+0/4(1).

Labrum ( Fig. 14C ): flat, free edge with 13 teeth.

Paragnaths: absent.

Mandible ( Fig. 14E ): pars incisiva with four teeth; pars molaris with six claws, the four distal ones denticulated, the two most proximal ones joined together; tooth of ventral triangular. Mandibular palp with one long article and seta reaching the distal end of the pars molaris.

Maxillula ( Fig. 14F ): proximal endite with four unequal claws; distal endite with six claws: two apical smooth and four denticulated; three smooth, unequal subterminal setae on the outer distal margin.

Maxilla ( Fig. 14G ): four-segmented, setal formula 3, 3,12,4.

Thoracopods I to VII ( Figs. 15A–G ): length slightly increasing from thoracopod one to five, last two similar in size. Epipod present in all thoracopod, about half or more of the length of the corresponding basipod. Basipod bearing one distolateral seta similar in length to the first article of the endopod in all thoracopods. Exopod of ThI slightly longer than the first two endopodal articles, exopod longer than endopod in ThIII to V and similar in length in thoracopod II, VI and VII. Exopod of all thoracopods with two distal setae on each article. Number of exopodal segments of Ths I to VII 3-4-4-4-4-4-4-4. Endopod four-segmented, first article shorter than second and third articles, which are similar in length, and article four small in all thoracopods; first and second article bearing an outer plumose seta in all thoracopods, two inner smooth setae on second and third article on ThI , and only one inner smooth seta on the second article on the rest of thoracopods; third article with one small outer distal seta on all thoracopods, ThI third article with also an inner seta; fourth article with two strong claws of different length and one smooth seta on all thoracopods. Setal formula of endopods as follow:

ThI 2+1/2+1/1+1/3(1)

ThII-VII 0+1/1+1/0+1/3(1)

Thoracopod VIII ( Fig. 14 H–K ): rectangular, elongated, longer than wide; penial region with massive protopod; long trapezoidal outer lobe with complete basal delimitation, reaching the distal end of basipod and fully defined at base in latero-external view. Dentate lobe with several distal teeth. Inner lobe very short. Basipod without setae, with anterior projection (or crest). Very small exopod with a pair of distal setae and small endopod with two distal setae.

Pleopod I ( Fig. 15H ): one segmented with a long smooth seta.

Uropod ( Fig. 16A , Appendix 8) sympod over two times longer than endopod and exopod, which are similar in length, and about five times as long as wide, with nine spines, the distal one slightly longer than the others (on one side, Fig. 16A ), while, on the other side, the second most distal spine is the longest (Appendix 8); spines occupy half of its length. Endopod with two distal strong spines and two inner ones smaller, with two long plumose dorsal setae that exceed the tip of the endopod and two distal barbed long setae. Exopod with five barbed setae, three terminal and two dorsal similar in length.

Pleotelson ( Fig. 16B ): with one very small plumose lateral seta on each side; anal operculum not protruded, flat.

Furca ( Fig. 16B ): rectangular rami, with eight (one side) and nine (other side) barbed spines, with the two distal ones longer and stronger. Two dorsal plumose setae, the inner one short and the outer one double the length of the distal spines.

Female differs from male in the small triangular ThVIII ( Fig. 14L ).

Variability: variability was observed in body size (males 0.96–1.13 mm and females 0.82–1.5 mm); number of teeth on labrum (11–14) ( Fig. 14D ), number of exopodal articles on the thoracopods (2–4); number of spines on sympod of uropod (5–9) and number of spines on furcal rami (7–10).

Distribution and remarks. N. vanweesae sp. nov. has been collected in four bores near Boolegeeda creek (Ashburton River) ( Fig. 6 , 9B ). This species was previously known by Biologic Environmental Surveys as Parabathynellidae sp. “Biologic-PBAT012”. N. vanweesae sp. nov. can be distinguished by the combination of characters listed in Supplementary Material Table S2. It is part of a partially supported clade ( Fig. 2 ) formed by one species collected in the Onslow River Catchment, and four species collected geographically close by in the Ashburton River Catchment ( N. nguyenae sp. nov., N. hueyi sp. nov., N. mittrai sp. nov., N. rodmani sp. nov.) ( Figs. 6 , 9B ).

Etymology. The name of the species is dedicated to a colleague, Mary van Wees, one of the collectors of this species.

Figures

FIGURE 2. Concatenated three-genes ML tree with collapsed nodes. Green nodes=supported clades. Orange nodes/ support=partially supported clades. * New taxa defined in this study. Blue star = putative species included in Nicolenella gen. nov.

FIGURE 6. Nicolenella gen. nov. species distribution in the Pilbara region.

FIGURE 9. Nicolenella gen. nov. species distribution in four areas of interest in rectangles in Fig 6 and Nicolenella pilbaraensis comb. nov. clade (from concatenated three-genes ML tree).

FIGURE 14. Nicolenella vanweesae sp. nov. (A–C, E–K) Male holotype (WAMC 79079). (A) Antennule (dorsal view); (B) Antenna (dorsal view); (C) Labrum; (D). Labrum (female paratype WAMC 79077); (E) Mandible; (F) Maxillule; (G) Maxilla (dorsal view); (H–K) Thoracopod VIII; (L) ThVIII (female paratype WAMC 79077 latero-external view). (O.Lb) outer lobe, (I.Lb) inner lobe, (D.Lb) dentate lobe; (Bsp) basipod, (Exp) exopod and (Endp) endopod. Scale bar in mm.

FIGURE 15. Nicolenella vanweesae sp. nov. (A–H) Male holotype (WAMC 79079). (A) Thoracopod I; (B) Thoracopod II; (C) Thoracopod III; (D) Thoracopod IV; (E) Thoracopod V; (F) Thoracopod VI; (G) Thoracopod VII; (H) Pleopod I. Scale bar in mm.

FIGURE 16. Nicolenella vanweesae sp. nov. (A–B) Male holotype (WAMC 79079). (A) Uropod (latero-external view); (D) Pleotelson and furcal rami (dorsal view). Scale bar in mm.