Nicolenella mittrai 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 : 46-50

Nicolenella mittrai Perina & Camacho , sp. nov.

( Figs. 12 , 13 , Appendix 7D)

urn:lsid:zoobank.org:act:

Material examined. Holotype female. AUSTRALIA: Western Australia: Brockman, Pilbara , bore RC17BS30052 ( stygo net haul), 22°33'42.1097"S, 117°23'55.8442"E, 19 October 2020, M. Lythe, S. Floeckner ( WAMC 79071 - BES8393 c-BMR02302, permanent slide).

Paratypes AUSTRALIA: Western Australia: 1 female, ( WAMC 79070 - BES8393 b-BMR02301, In ethanol) same details as holotype ; 1 male, ( WAMC 79072 - BES8393 d_ BMR02303 , permanent slide) and 1 male ( WAMC 79073 - BES8393 e-BMR02304, permanent slide) same details as holotype ; 1 juvenile, bore RC18BS30067 ( stygo net haul), 22°33`49.75"S, 117°23`31.96"E, 16 December 2018, S. Rodman, A. Slabber ( WAMC 79074 - BES4339 - BMR00541 , permanent slide) ; 1 female ( WAMC 79089 - BES4097 - BMR00544 , permanent slide) same details as WAMC 79074 ; 1 female, bore RC18BS30067, 16 April 2019, S. Callan, M. Lythe ( WAMC 82098 - BES6477 ) .

Additional material. AUSTRALIA: Western Australia: 1 male ( WAMC79076 - BES4459 - BMR00606 , in ethanol) same details as WAMC 79074 ; 1 female, bore RC18BS30067 ( stygo net haul), 16 April 2019, S. Callan, M. Lythe ( WAMC 79075 - BES6852 - BMR00419 , in ethanol) ; 1 female ( WAMC 79090 - BES6477 , in ethanol) same details as WAMC 82098 ; 1 female ( WAMC 79035 - BES4927 - BMR00601 , permanent slide) same details as WAMC 79089 .

Diagnosis. AI seven-segmented. AII six-segmented with sixth article as long as fourth and fifth combined. Mandibular palp one-segmented formed by one long segment 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, about 1.5 times as long as wide. Sympod of the uropod with non-homonomous spines, with the two distal ones slightly longer than others. 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 = 11.4–23.3% and 12S = 5–31.2% ( Table 3, Appendix 2, 3).

Description female holotype (WAMC 79071). Body length 0.93 mm. Body six times as long as maximum width, elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body (Appendix 7D).

Antennula ( Fig. 12A ): seven-segmented. Articles narrowing from the first to the last one. First article longest, followed by third, sixth, second and seventh, with the last two similar in length, fourth article is the shortest, followed by the fifth. Inner flagellum small. Article five with two and article six and seven with three terminal aesthetascs. Antennular setation as in Fig. 12A .

Antenna ( Fig. 12B ): six-segmented; slightly longer that the first two segments of A1, sixth segment as long as third and fourth combined. Setal formula: 0+0/0+0/1+1/1+1/0+0/4(1). Plumose seta of distal segment shorter than the longest smooth seta.

Labrum ( Fig. 12C ): flat, free edge with 12 teeth.

Paragnaths: absent.

Mandible ( Fig. 12D ): pars incisiva with four teeth; pars molaris with six strong claws, the two most proximal ones joined together; tooth of ventral edge small and triangular. Mandibular palp with one long distal seta reaching the end of the pars incisiva.

Maxillula ( Fig. 12E ): proximal endite with four unequal claws; distal endite with six claws: two apical smooth and four denticulate; three smooth subterminal setae on the outer distal margin.

Maxilla ( Fig. 12F ): four-segmented, setal formula 3, 3, 10, 4.

Thoracopods I to VII ( Figs. 13A–G ): length slightly increasing from thoracopod one to five, six and seven similar in length. Epipod present in all thoracopods, about half the length of the corresponding basipod, or less. All basipods with one distolateral seta about as long as the first article of the endopod. Exopod shorter than endopod in ThI and II, and about the same length in ThIII to VII. Exopod of all thoracopods with two very long distal setae on each article (ThVI has one exopod with three setae on the first article). Number of exopodal segments of thoracopods I–VII: 3-4-4-4-4-4-3. Endopod four-segmented, first article short, about half as long as the second and third, which are similar, and the fourth one very small in all thoracopods; first and second article of all thoracopods bearing an outer plumose seta; first and second article of ThI bearing two smooth inner setae, second article bearing one inner seta in other thoracopods; third article with one small outer distal seta on all thoracopods, and one inner seta on ThI only; fourth article with two strong claws of different length and one smooth seta on all thoracopods. Endopod four-segmented, setal formula:

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

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

Thoracopod VIII ( Fig. 12G ): small and conical.

Pleopod I ( Fig. 12H ): one-segmented with a long seta slightly longer than the length of the segment.

Uropod ( Fig. 13H ): sympod nearly three times as long as wide, with seven spines, the two distal one slightly longer, occupying about half of its length. Endopod as long as exopod, with a protrusion on disto-outer margin, two terminal and two inner spines, and two terminal, one subterminal, and one proximal seta. Exopod with two terminal, and two outer barbed setae.

Pleotelson ( Fig. 12I ): with one small lateral seta on each side; anal operculum not protruded.

Furca ( Fig. 12I ): sub-square, with two large distal spines and five smaller spines on inner margin, and two dorsal plumose setae of different length.

Male paratypes differ from female in the thoracopod VIII ( Fig. 13I,J ), which is compact, elongated, with penial region with massive protopod. Long rounded and bilobed outer lobe, reaching beyond the distal end of basipod, and not fully defined at base in latero-external view. Dentate lobe with several distal teeth. Basipod without setae and with anterior crest (or projection). Exopod with a pair of short setae, and endopod slightly longer, with two subequal distal setae.

Variability: variability was observed in body size (male 0.75–1.02 mm and females 0.92–1.04 mm), number of claws of pars molaris of Md (6–7), number of segments of exopod of ThI to VII (2/3-3/4-3/4-3/4-3/4-3/4-2/4), number on spines on sympod (6–10), and number of spines on furca (6–9).

Distribution and remarks. N.mittrai sp. nov. has been collected in two bores near Boolegeeda creek (Ashburton River) ( Fig. 6 , 9B ). This species was previously known by Biologic Environmental Surveys as Parabathynellidae sp. “Biologic-PBAT005”. N. mittrai sp. nov. can be distinguished by the combination of characters listed in Supplementary Material Table S2. It is part of a partially well-supported clade ( Fig. 2 ) formed by one species collected in the Onslow River Catchment, and four species collected geographically close in the Ashburton River Catchment ( N. nguyenae sp. nov., N. hueyi sp. nov., N. vanweesae sp. nov., N. rodmani sp. nov.) ( Figs. 6 , 9B ).

Etymology. The name of the species is dedicated to Anton Mittra, colleague who has extensively sampled stygofauna in the arid zones of WA.

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 12. Nicolenella mittrai sp. nov. (A, C–I) female holotype (WAMC 79071). (A) Antennule (dorsal view); (B) Antenna (dorsal view, male paratype WAMC 79072); (C) Labrum; (D) Mandible; (E) Maxillule; (F) Maxilla (dorsal view); (G) Thoracopod VIII; (I) Furca (dorsal 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 13. Nicolenella mittrai sp. nov. (A–H) female holotype (WAMC 79071). (A) Thoracopod I; (B) Thoracopod II; (C) Thoracopod III; (D) Thoracopod IV; (E) Thoracopod V; (F) Thoracopod VI; (G) Thoracopod VII; (H); Uropod (latero-external view); (I–J) Thoracopod VIII (male paratype WAMC 79073). (O.Lb) outer lobe, (I.Lb) inner lobe, (D.Lb) dentate lobe; (Bsp) basipod, (Exp) exopod and (Endp) endopod. Scale bar in mm.