Nicolenella floecknerae 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 : 66-69

Nicolenella floecknerae Perina & Camacho , sp. nov.

( Figs. 24 , 25 , Appendix 7I)

urn:lsid:zoobank.org:act:

Material examined. Holotype male. AUSTRALIA: Western Australia: Gudai Darri, Pilbara, Bore MB12 K58W018 ( stygo net haul), 22°32'23.2337"S, 119°00'32.1872"E, 12 March 2021, F. Rudin, S. Floeckner ( WAMC 82060 - BMR02725 - BES10759 , permanent slide). Female unknown.

Diagnosis. AI seven-segmented. AII seven-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 seven claws. Four or five articles on exopod of thoracopods. One internal seta on first article of endopod of ThII to VII. Male thoracopod VIII rectangular, about 1.5 times as long as wide. Sympod of the uropod with homonomous spines; exopod of the uropod slightly shorter than 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 = 18.2–25.4% and 12S = 21.3–31.4% ( Table 3, Appendix 2,3).

Description male holotype (WAMC 82060). Body length of 1.48 mm. Body over five and a half times as long as maximum width, elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body (Appendix 7I).

Antennula ( Fig. 24A ): seven-segmented, two times longer than AII. The first article is the longest, followed by the sixth, second and third similar in length and slightly longer than the fourth, fifth and seventh, which are similar in length and the shortest. Sixth and seventh articles respectively with two and three terminal aesthetascs. Antennular setation as in Fig. 24A .

Antenna ( Fig. 24B ): seven-segmented; the first two articles are similar in length and shortest; third, sixth and fifth similar in length and slightly shorter that article four, seventh segment is the longest and double article sixth. Setal formula of AII: 0+0/0+0/1+1/1+1/0+0/1+0/4(1).

Labrum ( Fig. 24C ): flat, free edge with 20 teeth.

Paragnaths: absent.

Mandible ( Fig. 24D ): pars incisiva with five teeth; pars molaris with eight claws, the six 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. 24E,F ): proximal endite with four unequal claws; distal endite with seven claws: two apical one smooth and the rest denticulated; three smooth, unequal subterminal setae on the outer distal margin.

Maxilla ( Fig. 24G ): four-segmented, setal formula 4, 4,13,1.

Thoracopods I to VII ( Figs. 25A–G ): length slightly increasing from thoracopod one to six, last two thoracopods similar in length. Epipod present in all thoracopods, about half or as more than half the length of the corresponding basipod. All basipods with one distolateral seta shorter than the first article of the endopod. Exopod of ThI and VII shorter than the first three articles of the endopod, exopod of ThII as long as the first three articles of endopod, and exopod of ThIII to V as long as endopod. Exopod of ThVI broken. Exopod of all thoracopods with two very long distal setae on each article. Number of exopodal segments of Ths I to VII: 4-5-5-5-5-3+-4. Endopod four-segmented in all thoracopods. First article shorter than article two and three, which are similar in length, and fourth article small in all thoracopods; first and second articles bearing an outer plumose seta, one smooth inner seta on article one and three smooth setae on article two in all thoracopods, except ThI that has three inner setae on the first article and ThVII that has two inner setae on the second article; third article with one outer distal seta on all thoracopods, and one inner seta on ThI ; fourth article very reduced with two strong claws of different length and two smooth seta on all thoracopods. Setal formula of endopods as follow:

ThI 3+1/3+1/1+1/4(2)

ThII to VI 1+1/3+1/0+1/4(2)

ThVII 1+1/2+1/0+1/4(2)

Thoracopod VIII ( Fig. 24H,I ): compact, longer than wider. Penial region with massive protopod. Outer lobe rounded, reaching beyond the distal end of basipod, and not defined at base. Dentate lobe with four teeth. Inner lobe rounded slightly shorter than outer lobe. Basipod with a frontal crest (or projection), without setae. Endopod small with two setae, and exopod with a small distal lump and no setae.

Pleopod I ( Fig. 25H ): one segmented with a short plumose seta.

Uropod ( Fig. 25I ): sympod one and a half times longer than endopod, and over three times as long as wide, with eight/nine (left and right) homonomous spines occupying about half of the length of the sympod. Endopod slightly longer than exopod, with two distal strong spines and three inner small one, two dorsal plumose setae that exceed the tip of the endopod and two long distal barbed setae. Exopod with six barbed setae, two terminal, three dorsal, and one basiventral seta.

Pleotelson ( Fig. 25J ): with one short lateral seta on each side; anal operculum not protruded.

Furca ( Fig. 25J ): rami rectangular, with 11 barbed spines, nine short proximal ones and two long and strong distal ones. Two dorsal plumose setae, the inner one short and the outer one reaches beyond the end of the distal spines.

The female of this species is unknown.

Distribution and remarks. N. floecknerae sp. nov. has been collected in one bore at the Gudai-Darri area, in the Fortescue River Catchment ( Fig. 9C ). This species was previously known by Biologic Environmental Surveys as Parabathynellidae sp. “Biologic-PBAT024”. N. floecknerae sp. nov. can be distinguished by the combination of characters listed in Supplementary material Table S2. It is sister to Parabthynellidae sp. 18 ( N. sp. 18) collected about 80 km southeast in the Fortescue River Catchment, and it is also genetically close to N. abramsae sp. nov., collected about 170 km north in the DeGrey River Catchment ( Fig. 6 ).

Etymology. The name of the species is dedicated to one of the collectors, Stephanie Floeckner, colleague who also has extensively worked on the genetics of Parabathynellidae .

Figures

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 24. Nicolenella floecknerae sp. nov. (A–G) Male holotype (WAMC 82060). (A) Antennule (dorsal view); (B) Antenna (dorsal view); (C) Labrum; (D) Mandible; (E) Maxillule, distal endite; (F) Maxillula. Proximal endite; (G) Maxilla; (H–I) Thoracopod VIII. (O.Lb) outer lobe, (I.Lb) inner lobe, (D.Lb) dentate lobe; (Bsp) basipod, (Exp) exopod and (Endp) endopod. Scale bar in mm.

FIGURE 25. Nicolenella floecknerae sp. nov. (A–J) Male holotype (WAMC 82060). (A) Thoracopod I; (B) Thoracopod II; (C) Thoracopod ThIII; (D) Thoracopod IV; (E) Thoracopod V; (F) Thoracopod VI; (G) Thoracopod VII; (H) Pleopod I, (I) Uropod (latero-external view); (J) Pleotelson and furca (dorsal view). Scale bar in mm.