Atopobathynella rudini Perina & Camacho, 2025

Perina, Giulia, Camacho, Ana I., Morgan, Liesel, Lawrie, Angus, Floeckner, Stephanie & Guzik, Michelle T., 2025, New species of Atopobathynella, Kimberleybathynella and Hexabathynella (Parabathynellidae, Bathynellacea) from the arid zones of Western Australia, Zootaxa 5655 (1), pp. 1-103 : 44-47

publication ID	https://doi.org/10.11646/zootaxa.5655.1.1
publication LSID	lsid:zoobank.org:pub:4411E6C2-D4C5-4340-AF6B-FDDBB0F7E1A1
DOI	https://doi.org/10.5281/zenodo.15822709
persistent identifier	https://treatment.plazi.org/id/0399C326-FF90-FFFC-53BB-06AAFAE0F9A9
treatment provided by	Plazi
scientific name	Atopobathynella rudini Perina & Camacho
status	sp. nov.

Treatment

Atopobathynella rudini Perina & Camacho , sp. nov.

urn:lsid:zoobank.org:act:7C8B688D-955B-4660-ADBB-B6E899E1DBA6

( Figs. 16–17 View FIGURE 16 View FIGURE 17 )

Material examined. Holotype female. AUSTRALIA: Western Australia: Brockman, Boolgeeda Creek, Pilbara , Karaman BS 4-KC08 22°34'29.2764"S, 117°11'10.1645"E, 21 August 2019, F. Rudin, P. Runham ( WAMC 78933 — BES6368 , permanent slide); 1 juvenile ( WAMC 78932 — BES7410 — BMR00527 View Materials ) in alcohol. Male unknown. GoogleMaps

Diagnosis. Atopobathynella rudini sp. nov. belongs to a group of Atopobathynella species that have distal endite of maxillula with five claws; sympod of the uropod with inhomonomous spines; exopod of the uropod similar in length to endopod, with two distal setae; anal operculum protruded. The sequenced specimens differ from all the other Atopobathynella taxa sequenced by 12S = 30.4–38% (Appendix 3, COI sequence was not used to calculate the p-distance as too short).

Description female holotype (WAMC 78933). Body length of 1.08 mm. Body eight and a half times as long as maximum width, elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body.

Antennula ( Fig. 16A View FIGURE 16 ): six-segmented, with articles rectangular. The first three articles are similar in length and 0.25 times longer that the remaining three, which are similar in length. Inner flagellum small, with three setae. Plumose setae absent in the internal angle of the distal end of the fourth segment, two typical outer plumose setae located on small protuberance, one short and one long, extending beyond the distal end of the fifth article. Ventral seta present in articles two and three. Articles five and six with three terminal aesthetascs each, similar in length on fifth article, and two long and one short on sixth article. Antennular setation as in Fig. 16A View FIGURE 16 .

Antenna ( Fig. 16B View FIGURE 16 ): one-segmented with three smooth setae, two terminal and one subterminal.

Labrum ( Fig. 16C View FIGURE 16 ): slightly convex, free edge with 16 teeth, seven on each side and two central ones.

Paragnaths: absent.

Mandible ( Fig. 16D View FIGURE 16 ): pars incisiva with three teeth; pars molaris with five claws, the most distal one modified with three pronounced distal teeth, thicker and separated from the rest, two most proximal claws joined together; tooth on ventral edge present and small. Mandibular palp with one distal seta (broken).

Maxillula ( Fig. 16E View FIGURE 16 ): proximal endite with four unequal claws; distal endite with five claws, the two distal smooth and the other three denticulated, the most basal one thinner than the rest; three smooth subterminal setae on the outer distal margin.

Maxilla ( Fig. 16F View FIGURE 16 ): four-segmented, setal formula 2, 4, 11, 1.

Thoracopods I to VII ( Figs. 17A–G View FIGURE 17 ): length slightly increasing from thoracopod one to five, decreasing from ThVI to VII. Epipod present in thoracopods II to VII (epipods of ThII of holotype broken, but present in the paratype WAMC 78932), of similar length to two-thirds of the corresponding basipod. All basipods with one distolateral seta as long as the first article of the endopod. Exopod one-segmented in all thoracopods, exopod of ThI, II and VII ( Fig. 12A,B,G View FIGURE 12 ) slightly shorter than the distal end of the second article of the endopod, exopod of ThIII and IV ( Fig. 12C,D View FIGURE 12 ) slightly longer than the distal end of the second article of the endopod, exopod of ThVI ( Fig. 12F View FIGURE 12 ) as long as the first two articles of the endopod; exopod of ThI with two distal setae, the outer one very short. Exopod of ThII to VII bearing three barbed setae, the two terminal ones of different length, with the outer one very short, about half the length of the subterminal seta. Endopod four-segmented, first article short, half the length of the second and third article, with one seta on ThI , and no seta on the other thoracopods; second and third articles long and similar in length in all thoracopods; second article with one outer plumose seta in all thoracopods, and one inner smooth seta on ThI only; third article with one inner seta on ThI only, and one very small outer seta on other thoracopods; fourth article very reduced with two strong claws of different length on thoracopod I and only one long strong claw on ThII to VII. Setal formula of endopods as follows:

ThI 1+0/1+1/1+0/2

ThII to VII 0+0/0+1/0+1/1

Thoracopod VIII ( Figs. 16G View FIGURE 16 ): very small, like a “little finger”.

Pleopod I ( Figs. 16H View FIGURE 16 ): one long plumose seta located on the anterior third of the first segment of the pleon on both sides.

Uropod ( Fig. 17H View FIGURE 17 ): sympod about four times as long as wide, and four times the length of the exopod and endopod, with seven (eight on the other side) inhomonomous spines, with the distal one bigger than the others, occupying the distal half of the sympod. Exopod with two terminal setae of different length (one barbed), and one long barbed basal seta. Endopod distally drawn out into a long dagger-shaped structure as long as the exopod, distolateral angle bearing one barbed and one smooth setae of different length, one reaching the distal end of dagger-shaped structure, and one twice as long.

Pleotelson ( Fig. 17I View FIGURE 17 ): with triangular anal operculum protruded. Lateral seta very short.

Furca ( Fig. 17I View FIGURE 17 ): rami robust and trapezoidal, with five barbed spines; three basal ones smaller than the two distal ones; distal spine thicker than the others. Two dorsal plumose setae of different lengths, the inner one reaches the end of the distal spine and the outer one is twice as long as the inner seta.

Distribution and remarks. Atopobathynella rudini has been collected from one site at the Boolgeeda Creek (a tributary of the Ashburton River), in the hyporheic habitat ( Fig. 1 View FIGURE 1 ). Atopobathynella rudini sp. nov. does not have any unique characters that distinguish it from all the others, however its combination of characters is unique (Appendix 5). It has a protruded anal operculum ( Fig. 17I View FIGURE 17 ), a character found in only five other species of the genus: A. schminkei (from Australia), A. compagana (from New Zealand), and three Indian species. This species was previously known by Biologic Environmental Surveys as Atopobathynella sp. “Biologic-PBAT014”. Despite being collected geographically close to the site where A. abelloana sp. nov. occurs ( Fig. 1 View FIGURE 1 ), this species is genetically distant to A. abelloana sp. nov. and to all other putative species of Atopobathynella sequenced so far ( Fig. 5 View FIGURE 5 ).