Nicolenella rodmani Perina & Camacho, sp. nov.

(Figs. 7, 8, Appendix 7B)

urn:lsid:zoobank.org:act: 72EA9544-E7EF-465C-88D0-FAF72737EB73

Material examined. Holotype male. AUSTRALIA: Western Australia: Brockman, Pilbara, bore RC17BS1E0314 (stygo net haul), 22°31'11.2861"S, 117°10'13.7302"E, 10 Jun 2019, S. Rodman, A. Williams (WAMC 78893- BES7089, permanent slide).

Paratypes AUSTRALIA: Western Australia: 1 female, Brockman, Pilbara, Bore RC17BS1E0304 (stygo net haul), 22°31'26.9409"S, 117°09'40.7110"E, 14 August 2019, F. Rudin, P. Runham (WAMC 79036-BES7560- BMR00645, permanent slide); 1 female, Brockman, Pilbara, Bore RC17BS1E0304(stygo net haul), 22°31'26.9409"S, 117°09'40.7110"E, 17 October 2020, M. Lythe, S. Floeckner (WAMC 79037-BES9110a-BMR02281, permanent slide); 1 male, same details as WAMC 79037 (WAMC 79038-BES9110d-BMR02284, permanent slide); 1 female, same details as WAMC 79037 (WAMC 79039-BES9110e-BMR02285, permanent slide).

Additional material AUSTRALIA: Western Australia: 1 juvenile, 1 female, (WAMC 79040 - BES7089, in ethanol) same details as holotype.

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, nearly two times as long as wide. Sympod of the uropod with non-homonomous spines, with the two distal ones slightly longer than the rest. Exopod and endopod similar in length; exopod without basiventral seta. Furca with few smaller inner spines and two distal ones more than 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 = 11.8–21.6% and 12S = 12.9–33.7% (Table 3, Appendix 2,3).

Description male holotype (WAMC 78893). Body length 1 mm. Body 7.5 times as long as maximum width, elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body (Appendix 7B).

Antennula (Fig. 7A): seven-segmented. Articles narrowing from the first to the last one. First article longest, followed by third, second and last articles, which are similar in length, and longer than fourth and fifth articles, sixth article shortest. Inner flagellum small.Article five with two and article six and seven with three terminal aesthetascs. Antennular setation as in Fig. 7A.

Antenna (Fig. 7B): six-segmented; slightly longer than the first two segments of A1, sixth segment as long as fourth and fifth ones 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. 7C): flat, free edge with 20 teeth.

Paragnaths: absent.

Mandible (Fig. 7D): pars incisiva with four teeth; pars molaris with six strong claws, the two most proximal ones joined together; tooth of ventral edge small, triangular and rounded. Mandibular palp with one long distal seta reaching almost the end of the pars incisiva.

Maxillula (Fig. 7E): 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. 7F): four-segmented, setal formula 3, 4, 8, 7.

Thoracopods I to VII (Figs. 8A–G): length slightly increasing from thoracopod one to two and four to five, two and three, and six and seven similar in length. Epipod present in all thoracopod, about half the length of the corresponding basipod. All basipods with one distolateral seta slightly shorter than the first article of the endopod. Exopod of Th I shorter than endopod, similar in length in ThII and VII, slightly longer than endopod in ThIII to VI. Exopod of all thoracopods with two very long distal setae on each article. Number of exopodal segments of Ths I to VII 3-4-4-4-4-4-4. Endopod four-segmented, first article short, 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 of Th II to VII bearing one inner seta; third article with one small outer distal seta on all thoracopods; 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+1/0+1/3(1)

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

Thoracopod VIII (Fig. 7G–J): almost rectangular, about twice as long as wide. Protopod big, with prominent penial region with terminal opening. Epipod (or outer lobe) large, sub-rectangular, distal part not reaching beyond exopod. Basipod sub-rectangular without setae, inner margin of basipod drawn out into projection (or crest). Dentate lobe with about 7 teeth, inner lobe short and subsquare. Exopod small without setae. Endopod bigger than exopod, with two terminal setae.

Pleopod I (Fig. 8H): one-segmented with a long seta 2.5 times the length of the segment.

Uropod (Fig. 8I): 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 (zoom of Fig. 8I), 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. 8J): with one small lateral plumose seta on each side; anal operculum not protruded.

Furca (Fig. 8J): trapezoidal, about 1.6 times longer than wide, with two large distal spines and seven smaller spines on inner margin, and two dorsal plumose setae of different length.

Female paratypes differ from male in the small pointy thoracopod VIII (Fig. 7K).

Variability: variability was observed in body size (male 1 mm and females 0.70–0.85 mm), number of claws of pars molaris of mandible (4 to 6), number of segments of exopod of ThI to VII (2-3-3-3-4-3-2/3) and therefore length of exopod with respect to endopod of thoracopods (shorter or same length of endopod, where the holotype has exopod longer than endopod).

Distribution and remarks. N.rodmani 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-PBAT003”. N. rodmani 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. mittrai sp. nov., N. vanweesae sp. nov., N. hueyi sp. nov.) (Figs. 6, 9B).

Etymology. The name of the species is dedicated to a colleague, Syngeon Rodman, one of the collectors of this species.