Nicolenella abramsae Perina and 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 : 32-38

Nicolenella abramsae Perina and Camacho sp. nov.

( Figs. 3–5 , Appendix 7A)

urn:lsid:zoobank.org:act:

Material examined. Holotype male. AUSTRALIA: Western Australia: Miralga creek, Pilbara , bore ALB0005 ( stygo net haul), 20°47'32.2459"S, 119°19'00.7342"E, 16 May 2019, D. Main, P. Runham ( WAMC 78891 - BES8291 , permanent slide).

Paratypes AUSTRALIA: Western Australia: 1 male, bore ALB0003, ( stygo net haul), 20°57'45.9186"S, 119°17'48.2640"E, 11 July 2019, D. Main, P. Runham ( WAMC 78889 - BES7048 , permanent slide) ; 1 male, bore ALB0003, 16 May 2019, D. Main, P. Runham ( WAMC 78890 - BES7300 , permanent slide) ; 1 female ( WAMC 78892 - BES8292 , permanent slide), same details as holotype ; 1 female, bore ALB0066 ( stygo net haul), 20°46'32.5898"S, 119°19'10.9398"E, 7 November 2019, F. Rudin, M. Lythe ( WAMC 78895 - BES8295 , permanent slide) ; 1 male ( WAMC 78896 - BES8341 , permanent slide), same details as WAMC 78895 ; 1 male, bore ALB0067 ( stygo net haul), 20°46'38.4946"S, 119°19'09.2600"E, 7 November 2019, F. Rudin, M. Lythe ( WAMC 78897 - BES8342 , permanent slide) ; 1 female, bore ALB0010, ( stygo net haul), 20°47'31.1028"S, 119°19'00.8501"E, 11 July 2019, D. Main, P. Runham, ( WAMC 78899 - BES8344 , permanent slide) .

Additional material. AUSTRALIA: Western Australia: 3 females, 2 males, 1 juvenile, ( WAMC 82082 - BES6039 , in ethanol), same details as holotype ; 1 male, 2 females, bore ALB0005, 7 November 2019, F. Rudin, M. Lythe ( WAMC 82083 - BES6709 , in ethanol) ; 27 specimen, bore ALB0005, 11 July 2019, D. Main, P. Runham, ( WAMC 82084 - BES7059 , in ethanol) ; 1 male, 1 female, bore ALB0063, ( stygo net haul), 20°46'32.5142"S, 119°19'10.9135"E, 12 September 2019, Fabian Rudin, Phil Runham ( WAMC 82085 - BES6575 , in ethanol) ; 1 male ( WAMC 78894 - BES8294 , in ethanol), same details as WAMC 82085 ; 5 males, 4 females ( WAMC 82086 - BES6607 , in ethanol) same details as WAMC 78895 ; 1 male, 1 female ( WAMC 82087 - BES6467 , in ethanol) same details as WAMC 78897 ; 1 male ( WAMC 78898 - BES8343 , in ethanol) same details as WAMC 78897 ; 1 male, 1 female, 1 juvenile ( WAMC 82088 - BES7070 , in ethanol) same details as WAMC 78899 ; 1 male, 5 juveniles, bore ALB0010, 16 May 2019, D. Main, P. Runham, ( WAMC 82089 - BES7187 , in ethanol) ; 1 male ( WAMC 78900 - BES8345 , in ethanol) same details as WAMC 82089 ; 1 female, bore ALB0010, 12 September 2019, ( WAMC 82090 - BES6181 , in ethanol) ; 1 male, 1 female, bore ALB0063, 10 July 2019, D. Main, P. Runham, ( WAMC 78907 - BES7313 , in ethanol) ; 1 male, 1 female, bore ALB0066, 16 May 2019, D. Main, P. Runham, ( WAMC 78908 - BES7174 , in ethanol) ; 2 females, 2 juveniles, bore ALB0066, D. Main, P. Runham, ( WAMC 82091 - BES7265 , in ethanol) ; 2 females, 1 juvenile, bore ALB0067, 16 May 2019, D. Main, P. Runham, ( WAMC 82092 - BES6755 , in ethanol) ; 2 males, 1 female, bore ALB0067, 10 July 2019, D. Main, P. Runham, ( WAMC 82093 - BES7263 , in ethanol) .

Diagnosis. AI seven-segmented.AII six-segmented with fifth article very short. 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 seven claws. Three to five articles on exopod of thoracopods. One internal seta on first article of endopod of ThII to VII. Male thoracopod VIII trapezoidal, about 1.5 times as long as wide. Sympod of the uropod with non-homonomous spines, with one or two distal spines longer than others; 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 Table S2. The sequenced specimens differ from all the other Nicolenella gen. nov., Billibathynella and Brevisomabathynella species sequenced by COI = 18.5–24.8% and 12S = 23.9–33.2% ( Table 3, Appendix 2, 3).

Description male holotype (WAMC 78891). Body length 1.18 mm. Body nearly six times as long as maximum width elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body (Appendix 7A).

Antennula ( Fig. 3A ): seven-segmented, over two times longer than AII The first article is the longest, followed by the second, third and sixth articles, which are similar in length, fourth and fifth articles similar in length and the shortest, seventh article slightly longer. The last two articles with three terminal aesthetascs and the fifth one with only two. Antennular setation as in Fig. 3A .

Antenna ( Fig. 3B ): six-segmented; the first three articles and the fifth are similar in length and very short; the fourth article is twice as long as the fifth, the last article is the longest and about three times the length of the fifth. Setal formula of AII: 0+0/0+0/1+1/1+1/0+0/4(1).

Labrum ( Fig. 3C ): flat, free edge with 14 teeth.

Paragnaths: absent.

Mandible ( Fig. 3D ): pars incisiva with four teeth; pars molaris with seven claws, the five distal denticulated, the two most proximal ones joined together; tooth of ventral edge triangular. Mandibular palp with one long article and the seta reaching the distal end of the pars distalis.

Maxillula ( Fig. 3E ): proximal endite with four unequal claws, the most proximal long and strong; distal endite with seven claws: two apical smooth and five denticulated; three smooth, unequal subterminal setae on the outer distal margin.

Maxilla ( Fig. 3F ): four-segmented, setal formula 3, 4,11, 4.

Thoracopods I to VII ( Figs. 4A–G ): length slightly increasing from thoracopod one to two, last five similar in size. Epipod present in all thoracopods, about half of the length of the corresponding basipod. All basipods with one distolateral seta similar or shorter than the first article of the endopod. Four-segmented exopod in thoracopod I, VI and VII and five-segmented on the rest of thoracopods; exopod of thoracopod I and VII shorter than corresponding three first articles of the endopod. Exopod of all thoracopods with two very long distal setae on each article. Number of exopodal segments of thoracopods I to VII: 4-5-5-5-5-4-4. Endopod four-segmented, first article short, half as long as the second and third, which are similar in length, and the fourth one is small in all thoracopods; first and second articles bearing an outer plumose seta and one smooth inner seta in all thoracopods, but ThI second article bears three inner setae; third article with one small outer distal seta on all thoracopods and one inner seta on ThI ; fourth article very reduced with two strong claws of different length on all thoracopods and one smooth seta on ThI, II, VI and VII and two on ThIII to V. Setal formula of endopods as follow:

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

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

ThIII to V 1+1/1+1/0+1/4(2)

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

Thoracopod VIII ( Fig. 5A–D ): compact, longer than wide. Penial region with massive protopod with frontal protrusion similar to the outer and the dentate lobe. Outer lobe rounded, reaching the distal end of basipod, and not defined at base in latero-external view. Dentate lobe with several distal teeth. Inner lobe trapezoidal slightly longer than outer lobe. Basipod reaching the penile projection, without seta. Endopod and exopod small with one spine-like seta each.

Pleopod I ( Fig. 5F ): one segmented with a long smooth seta.

Uropod ( Fig. 5G ): sympod nearly twice as long as the endopod and four times as long as wide, with six (on one side) and seven spines on the other ( Fig. 5G ), with one or two distal spines slightly longer, occupying about half of the length of the sympod. Endopod as long as exopod, with two distal strong spines and three inner small ones, two dorsal plumose setae that exceed the tip of the endopod and two long distal barbed setae. Exopod with four barbed setae, two terminal and two dorsal.

Pleotelson ( Fig. 5H ): with one small plumose lateral seta on each side; anal operculum not protruded.

Furca ( Fig. 5H ): rami rectangular, with six and seven barbed spines; the five/six proximal thick and short and the two distal similar in size and twice the length of the basal ones. Two dorsal plumose setae, the inner one short and the outer one reaches the end of the distal spines.

Female paratype differs from male in the small cone-shape thoracopod VIII ( Fig. 5E ), the last segment of AII of female paratype WAMC 78892 is partially divided ( Fig. 3G ).

Variability: variability was observed in body size (males 0.83–1.18 mm and females 0.77–1.38 mm), number of teeth on labrum (10–14); number of exopodal articles on the thoracopods (3–5); number of spines on sympond of uropod (4–7) and number of spines on furcal rami (6–9). Some specimens have last article of AII partially divided ( Fig. 3G ).

Distribution and remarks. N. abramsae sp. nov. has been collected from six bores near Miralga creek, in the DeGrey River Catchment ( Fig. 6 ). This species was previously known by Biologic Environmental Surveys as Parabathynellidae sp. “Miralga”. N. abramsae sp. nov. can be distinguished by the combination of characters listed in Supplementary Material Table S2. It results genetically closely related to N. floecknerae sp. nov. and Parabathynellidae sp. 18 ( N. sp. 18) both collected from the Fortescue River Catchment, about 200 and 250 km south and southeast ( Fig. 6 ).

Etymology. The name of the species is dedicated to Kym Abrams, colleague who works on subterranean fauna and described a few species of Parabathynellidae from Australia using an integrative approach.

Figures

FIGURE 3. Nicolenella abramsae sp. nov. (A–F) Male holotype (WAMC78891). (A) Antennule (dorsal view); (B) Antenna (dorsal view); (C) Labrum; (D) Mandible; (E) Maxillule; (F) Maxilla (dorsal view); (G) Antenna (female paratype WAMC 78892). Scale bar in mm.

FIGURE 4. Nicolenella abramsae sp. nov. (A–G) Male holotype (WAMC78891). (A) Thoracopod I; (B) Thoracopod II; (C) Thoracopod III; (D) Thoracopod IV; (E) Thoracopod V; (F) Thoracopod VI; (G) Thoracopod VII. Scale bar in mm.

FIGURE 5. Nicolenella abramsae sp. nov. (A–D, F–H) Male holotype (WAMC78891).(A–D) Thoracopod VIII (latero-internal view); (B–C) Thoracopod VIII (latero-external view); (E) Thoracopod VIII (female paratype WAM C78892); (F) Pleopod; (G) Uropod (latero-external view); (H) Furcal rami (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 6. Nicolenella gen. nov. species distribution in the Pilbara region.