Atopobathynella shawensis 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 : 40-44

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.15822707
persistent identifier	https://treatment.plazi.org/id/0399C326-FF9C-FFF9-53BB-0306FD71FC79
treatment provided by	Plazi
scientific name	Atopobathynella shawensis Perina & Camacho
status	sp. nov.

Treatment

Atopobathynella shawensis Perina & Camacho , sp. nov.

urn:lsid:zoobank.org:act:B450C87A-ED9B-4644-8825-9318275866DF

( Figs. 14–15 View FIGURE 14 View FIGURE 15 )

Material examined. Holotype male. AUSTRALIA: Western Australia: Miralga Creek, Shaw River, Pilbara , karaman MCK004, 20°41'43.5454"S, 119°19'50.4250"E, 10 July 2019, D. Main, P. Runham ( WAMC 78888 — BES8290 permanent slide). GoogleMaps

Paratypes: 1 female ( WAM C78887 About WAM — BES8289 ), permanent slide, same details as holotype ; 1 male ( WAMC 82096 — BES7211 ) permanent slide, same details as holotype ; 1 female ( WAMC 82097 — BES7211 ) permanent slide, same details as holotype .

Additional material: 4 males, 4 females, 5 juveniles in ethanol ( WAMC 78938 — BES7211 ), same details as holotype .

Diagnosis. Atopobathynella shawensis sp. nov. belongs to a group of Atopobathynella species that have antennal organ (AO) without protuberance and with two strong setae, which reaches beyond half the length of article three; distal endite of maxillula with five claws; sympod of the uropod with inhomonomous spines; exopod of the uropod with two distal setae. It differs from all other species by the presence of a trapezoidal outer lobe, bilobed basipod on male ThVIII, and anal operculum slightly protruded. The sequenced specimens differ from all the other Atopobathynella species sequenced by COI = 11.2–20.5.0% (Appendix 2; 12S sequences not obtained).

Description male holotype (WAMC78888). Body length of 0.83 mm. Body about seven and a half times as long as maximum width, elongated, almost cylindrical, segments slightly widening and lengthening towards posterior end of body.

Antennula ( Fig. 14A View FIGURE 14 ): six-segmented. AO represented by two thick setae with no protuberance. Articles one to five thick, rectangular, sixth article half the thickness of the others. First two articles similar in length and longest, third and sixth articles similar in length and slightly shorted than first two, fourth and fifth articles similar in length and slightly shorter than others. Antennal organ represented by one ventral seta which reaches half the length of article three. Inner flagellum small and square with three setae. Plumose setae absent on the internal angle of the distal end of the fourth segment, two typical outer plumose setae present, one short and one long extending beyond the distal end of fifth article, both on the typical protuberance. Articles five and six with three terminal aesthetascs each. Antennular setation as in Fig. 14A View FIGURE 14 .

Antenna ( Fig. 14C View FIGURE 14 ): one-segmented with three smooth setae, two terminal and one subterminal.

Labrum ( Fig. 14D View FIGURE 14 ): flat, free edge with 12 main teeth.

Paragnaths: absent.

Mandible ( Fig. 14E View FIGURE 14 ): pars incisiva with three teeth; pars molaris with five claws, the most distal denticulated, thicker and on about a 45˚ angle from the others, the two most proximal claws joined together; tooth on ventral edge absent. Mandibular palp with one distal seta that does not reach the distal end of the pars molaris.

Maxillula ( Fig. 14F View FIGURE 14 ): proximal endite with four unequal claws; distal endite with five claws, two distal ones smooth and other three ones denticulated, the most basal claw thinner than others; three smooth subterminal setae on the outer distal margin.

Maxilla ( Fig. 14G View FIGURE 14 ): four-segmented, setal formula 2, 4, 10, 1.

Thoracopods I to VII ( Figs. 15A–G View FIGURE 15 ): length slightly increasing from ThI to IV, ThV is the longest, ThVI and VII shorter than ThV. Epipod present in all thoracopods, about half of the length of the corresponding basipod, except in ThVII, which is one third the length of the basipod. All basipods with one distolateral seta similar in length or slightly longer than the first article of the endopod. Exopod one-segmented in all thoracopods; exopod of ThI ( Fig. 10A View FIGURE 10 ) reaching the distal end of the second article of the endopod and bearing two terminal barbed setae; exopod of ThII to VII longer than the first two articles of the endopod and bearing three barbed setae, two terminal ones of different length, with the outer one shorter than the inner one, subterminal seta slightly longer than outer seta on all thoracopods; internal distal seta of exopod reaching the distal end of the longest claw of the endopod article four in ThII, slightly shorter in ThI , and extending beyond in the rest of thoracopods. Endopod four-segmented, first article short, about half the length of the second and third article, with one inner seta on ThI , and no seta on 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 and one small outer seta on the rest of thoracopods; fourth article very reduced with two strong claws of different length and one seta on ThI , and one long strong claw on thoracopod II to VII. Setal formula of endopods as follows:

ThI 1+0/1+1/1+0/3(1)

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

Thoracopod VIII ( Figs. 14H–I View FIGURE 14 ): compact, like a balloon. Penial region with massive protopod. Trapezoidal outer lobe, not reaching the distal end of basipod, well defined at base in latero-external view. Inner and dentate lobe similar to outer lobe in size and shape. Dentate lobe with two teeth like small spines. Basipod without delimited base, with two blunt lobes, with basipodial seta. One seta on basipod of uncertain origin.

Pleopod I ( Figs. 15H View FIGURE 15 ): one long plumose seta located on the anterior third of the first segment of the pleon in both sides.

Uropod ( Fig. 15I View FIGURE 15 ): sympod almost four times as long as wide, about three times the length of the exopod and almost four times the length of endopod, with seven inhomonomous spines occupying the distal half of the sympod, with distal spine bigger. Exopod with two terminal barbed setae of different length, and one short basal plumose seta. Endopod distally drawn out into a very long dagger-shaped structure longer than the exopod, distolateral angle bearing two plumose setae, the outer one a third longer than the inner one and almost twice the length of the dagger-shaped structure.

Pleotelson ( Fig. 15J View FIGURE 15 ): with one plumose lateral seta one each side; anal operculum slightly protruded.

Furca ( Fig. 15J View FIGURE 15 ): rami robust and trapezoidal, with six barbed spines; three basal ones smaller, just over half the length of the distal spines, two distal spines longest. Two plumose dorsal setae, inner seta very short and outer seta about twice the length of distal spines.

Female paratype differs from male in the second antennular segment ( Fig. 14B View FIGURE 14 ) that bears no antennal organ, but one smooth seta, and in the small denticle-like thoracopod VIII ( Fig. 14J View FIGURE 14 ).

Variability: was observed in body length (males: 0.83–094 mm, females 1.19–1.31), number of spines on sympod (five to seven), and number of spines on furca (six–seven).

Distribution and remarks. Atopobathynella shawensis sp. nov. has been collected from one site in hyporheic habitat near the Shaw River (a tributary of the De Grey River Catchment, Fig. 1 View FIGURE 1 ). Atopobathynella shawensis sp. nov. has the outer seta on uropodal exopod longer than the inner one, as in the three Indian species A. indica , A. nellorensis and A. inopinata ( Bandari et al., 2017) , and this is the character initially described as a defining character for the genus Kimberleybathynella . It forms a monophyletic clade with A. yarriensis and A. sp. PBAT031 ( Fig. 5 View FIGURE 5 ), collected in a perched aquifer at Yarrie Ridge and in the hyporheic environment at the McPhee Creek respectively, both in the De Grey Catchment ( Fig. 1 View FIGURE 1 ).

Etymology. The name of the species derives from the Shaw River in the Pilbara (a tributary of the De Grey River Catchment) where this species was collected.