taxonID	type	description	language	source
2B57DABA52C05C8295AFCFC481B2979D.taxon	description	Figs 11, 12, 13, 14, 15, 16, 17	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
2B57DABA52C05C8295AFCFC481B2979D.taxon	etymology	Etymology. The specific epithet keepuikantun means “ blind ” in Timbisha Shoshone (literally “ no eye having ”, kee (no / negative) pui (eye) katün (possession or having )) is given in reference to the lack of eyes and the location of Devils Hole II within Death Valley, the homeland of the Timbisha Shoshone Tribe. This name was selected in consultation with the Timbisha Shoshone Tribal Historic Preservation Office.	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
2B57DABA52C05C8295AFCFC481B2979D.taxon	diagnosis	Diagnosis. Small sized, stygomorphic species distinguished from congeners — except members of the H. muerta and H. cretae complex — by the combination of the following characters: eyes absent; antenna 1 longer than antenna 2; pleonites lacking dorsoposterior carinae; maxilla 1 inner plate with 2 apical pappose setae; male uropod 1 inner ramus lacking long curved setae. Differentiated from H. muerta and other members of the H. cretae complex by the combination of the following characters: maxilliped inner plate with 4 apical robust setae; male gnathopod 2 palmar margin with weak anterior notch; pereopod 7 basis projecting <1.2 × the length of the ischium, with <5 posterior setae, all simple, length 25 % remainder of the pereopod segments; uropod 3 ramus with robust setae; telson with 4 apical setae.	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
2B57DABA52C05C8295AFCFC481B2979D.taxon	description	Description. Holotype male (Figs 3 C, 11 – 15): 3.48 mm in length. Eyes and integumentary pigment absent (Fig. 3 C). Antennae. Antenna 1 (Fig. 11 A): approximately 1.4 × length of antenna 2; peduncle segment 1 with posterodistal robust seta; primary flagellum with 9 segments, aesthetascs on distal segments, aesthetascs shorter than respective segments, antepenultimate 3 segments with paired aesthetascs. Antenna 2 (Fig. 11 B): approximately 25 % body length, gland cone distinct; peduncular segment 5 subequal in length to segment 4; flagellum with 8 segments. Mouthparts. Mandibles: left mandible (Fig. 11 C): incisor 8 - dentate, lacinia mobilis 5 - dentate, accessory setal row with 3 plumose setae; molar process well-developed, cylindrical triturative, with plumose seta. Right mandible (Fig. 11 D): incisor 7 - dentate, lacinia mobilis trifid, lobes with numerous fine dentations; accessory setae row with 2 plumose setae; molar similar in form to left mandible. Upper lip (Fig. 12 A): rounded, apical margin of labrum with numerous setules. Lower lip (Fig. 12 B): inner lobes indistinct, outer margin of inner and outer lobes covered in setules; face of lip covered in pubescent setules. Maxilla 1 (Fig. 12 C): inner plate shorter than outer plate, with 2 apical pappose setae, and fine pubescent setules covering the entire plate; outer plate with 9 apical serrate setae, pubescent setules sparse decreasing laterally and proximally; palp one-segmented, vestigial, 20 % length of outer plate, tapering strongly distally, with sparse pubescent setules, palp emerges at approximately 70 % the length of the outer plate. Maxilla 2 (Fig. 12 D): both inner and outer plates covered in pubescent setules; outer plate subequal in length to inner plate, with numerous apical setae; inner plate narrowing slightly distally with numerous apical setae and 2 pappose facial setae. Maxilliped (Fig. 12 E): inner plate shorter than outer plate with 4 unarmed cuspidate setae along apical margin, surface of plate covered in pubescent setules; outer plate with numerous setae, lacking pubescent setules; palp 4 - segmented, second and third segments with numerous marginal, submarginal setae; dactylus surface lacking comb-scales, nail not elongate. Gnathopods. Gnathopod 1 (Fig. 13 A): coxal plate with 4 short apical setae; basis narrowing proximally, distoposterior surface of segment lacking comb-scales; ischium with a posterior seta; merus with 3 posterior setae, distoposterior surface of segment lacking comb-scales; carpus subequal in length to propodus, with cluster of posterior serrulate setae; propodus 1.3 × longer than broad with 5 inner medial serrulate setae, anterodistal corner with tuft of setae, sparse comb-scales present along posterior margin; palm straight, with 5 – 9 setae on inner / outer margins; defining angle straight with 2 robust setae; dactylus with plumose seta on outer margin and 3 inner setae, surface lacking comb-scales. Gnathopod 2 (Fig. 13 B): coxal plate with 3 short apical setae; basis narrowing weakly proximally; ischium with a posterior seta; merus with 3 posterior setae, distoposterior surface of segment lacking comb-scales; carpus 40 % length of propodus, posterior margin lobate, 33 % breadth of segment, lacking comb-scales; propodus enlarged, powerful, 1.1 × longer than broad, with tuft of anterodistal setae, posterior setae absent; palm straight, irregular with weak anterior notch, palm with 9 inner and 11 outer robust setae; defining angle weak, projecting slightly past carpus posterior lobe, with 2 robust setae arranged around notch where tip of dactylus rests, comb-scales present apically; dactylus with plumose seta on outer margin placed proximally and 3 inner setae. Pereopods. Pereopod 3 (Fig. 14 A): coxal plate with 5 short apical setae, plate not excavated posteroproximally; basis much longer than coxal plate lacking posterior marginal setae; merus subequal in length to carpus; carpus 80 % length of propodus; dactylus 50 % length of propodus, with plumose seta placed proximally on outer margin and 2 setae inserted adjacent to base of nail. Pereopod 4 (Fig. 14 B): coxal plate with 4 short apical setae, plate excavated posteroproximally; basis much longer than coxal plate lacking posterior marginal setae; merus subequal to carpus in length; carpus subequal in length to propodus; dactylus 50 % length of propodus, setation as in pereopod 3. Pereopod 5 (Fig. 14 C): coxal plate large, bilobate, anterior / posterior lobes both with a seta; basis posterior margin weakly convex, with 4 short setae, posterodistal corner convex, anterior margin with 4 robust setae; merus subequal in length to carpus; carpus 70 % length of propodus, dactylus 40 % length of propodus, with plumose seta placed proximally on posterior margin and 2 setae inserted adjacent to base of nail. Pereopod 6 (Fig. 14 D): coxal plate large, bilobate, with produced posterior lobe; basis posterior margin straight to convex, with 3 short setae, posterodistal corner straight, anterior margin with 2 robust setae; merus subequal in length to carpus; carpus 85 % length of propodus; dactylus 40 % length of propodus, setation as in pereopod 5. Pereopod 7 (Fig. 14 E): coxal plate diminutive, lobes indistinct; basis posterior margin weakly convex, projecting 1.1 × past the ischium, with 4 short setae extending to start of posterodistal corner, robust setae absent, posterodistal corner rounded, anterior margin with 2 robust setae, basis length 25 % remainder of pereopod segments; merus 70 % length of carpus; carpus 90 % length of propodus; dactylus 50 % length of propodus, setation like pereopods 5 and 6. Gills. Coxal gills present on somites 2 – 7, sternal gills present on somites 3 – 6 (Figs 13 B, 14 A-E). Pleon. Pleosome somites lacking dorsoposterior carinae. Epimera (Fig. 15 A): first epimeron ventral margin unarmed, distoposterior corner not produced, posterior margin with a single seta; second and third epimera like first in form, each with a posterior seta placed more medially. Pleopods (Fig. 15 B): peduncle of pleopod 1 90 % length of rami, with 2 coupling hooks lacking setae; outer, inner rami with 3 and 6 segments respectively. Pleopod 2 peduncle similar to first, with 2 coupling hooks; outer, inner rami with 3, 6 segments respectively. Pleopod 3 peduncle similar to first and second, with 2 coupling hooks; outer, inner rami with 3, 5 segments respectively. Urosome. Somites free, bare dorsally. Uropod 1 (Fig. 15 C): peduncle 1.3 × length of inner ramus with 4 outer robust setae and an inner robust seta; rami narrowing slightly distally, outer ramus with 1 marginal robust seta, and 4 apical robust setae; inner ramus 90 % length of outer ramus with 5 apical robust setae, marginal robust setae lacking. Uropod 2 (Fig. 15 D): peduncle subequal in length to inner ramus with 1 inner robust seta and 2 outer robust setae; rami not narrowing distally, outer ramus with 1 marginal robust seta, and 5 apical robust setae; inner ramus subequal in length to outer ramus, with 5 apical robust setae, marginal robust setae lacking. Uropod 3 (Fig. 15 E): diminutive, uniramous; peduncle 2 × length of ramus, with a robust seta and a simple seta; ramus with 2 robust setae. Telson (Fig. 15 F): fleshy, rounded, not narrowing distally, as long as broad, with 4 distal setae and 2 triplets of submarginal plumose setae flanking outer margins, apical margin not produced. Female (Figs 3 D, 16, 17): Allotype, USNM 1694155, 3.62 mm in length. Differing from male in presence of weaker gnathopods with weaker carpals / propodi, and minor differences in uropod and telson setation. Structures not described below as in male. Gnathopods. Gnathopod 1 (Fig. 16 A): coxal plate with 5 short apical setae, basis narrowing proximally, lacking marginal posterior setae; ischium with 1 posterior seta; merus with 2 posterior setae, distoposterior surface of segment lacking comb-scales; carpus 90 % length of propodus, with a medial seta and a cluster of posterior serrulate setae, posterior surface of segment with comb-scales; propodus 1.2 × longer than broad with 3 inner medial serrulate setae, anterodistal corner with tuft of setae, comb-scales present along posterior margin; palm straight with 5 – 10 setae on inner / outer margins; defining angle straight with 3 robust setae; dactylus with plumose seta on outer margin, and 3 inner marginal setae, surface lacking comb-scales. Gnathopod 2 (Fig. 16 B): coxal plate with 4 short apical setae, basis narrowing proximally, lacking marginal posterior setae; ischium with 1 posterior seta; merus with 2 posterior setae, distoposterior surface of segment lacking comb-scales; carpus 70 % length of propodus, posterior margin lobate, with sparse comb-scales; propodus 1.4 × longer than broad, with 3 inner medial setae, anterodistal corner with tuft of setae, comb-scales present along posterior margin; palm straight with 5 – 12 setae on inner / outer margins; defining angle with 2 robust setae and 4 additional submarginal robust setae; dactylus with plumose seta on outer margin, and 3 inner marginal setae, surface lacking comb-scales. Brood plates. (Fig. 16 B): large setaceous brood plates present on somites 2 – 5, decreasing in size posteriorly. Urosome. Somites free, bare dorsally. Uropod 1 (Fig. 17 A): peduncle 1.4 × length of outer ramus with 5 outer robust setae and an inner seta; rami narrowing slightly distally, outer ramus with 3 marginal robust setae, and 4 apical robust setae; inner ramus 90 % of outer ramus with 5 apical robust setae, lacking marginal robust setae. Uropod 2 (Fig. 17 B): peduncle subequal to rami, with 1 inner seta and 2 outer robust setae; rami not narrowing distally, outer ramus with 1 marginal robust seta, and 4 apical robust setae; inner ramus subequal in length to outer ramus with 5 apical robust setae, marginal robust setae absent. Uropod 3 (Fig. 17 C): diminutive, uniramous; peduncle 1.5 × length of ramus, with a robust seta and a seta; ramus with 3 robust setae. Telson (Fig. 17 D): fleshy, rounded, not narrowing distally, as long as broad, with 4 distal setae and 3 pairs of submarginal plumose setae flanking outer margins, apical margin not produced.	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
2B57DABA52C05C8295AFCFC481B2979D.taxon	distribution	Distribution and ecology. Hyalella keepuikantun sp. nov. is known only from its type locality, Devils Hole II (also known as Devils Hole Cave), in Nye County, Nevada, USA. Devils Hole II is located ~ 200 m north of Devils Hole, and is a separate cave system, manifesting as a small pit opening one meter by half a meter, then opening up to a nearly vertical pit ~ 40 m deep where it meets the water table (Hoffman 1988). As a result, Devils Hole II is less exposed when compared to its sister site, and epigean species such as the Devils Hole pupfish (Cyprinodon diabolis) are absent (Hoffman 1988). An unidentified species of Ostracoda has been found co-occurring with H. keepuikantun, but no other known species of aquatic invertebrates have been found in Devils Hole II (Kevin Wilson personal communication). Surveys of the cave have noted water depths of at least 21 meters, but the total depth is likely significantly deeper; its connections to Devils Hole and the rest of the basin remain unknown (Hoffman 1988). Hyalella keepuikantun sp. nov. has only been found near the surface of the water in Devils Hole II, where it was collected near bat guano and small, floating, calcite rafts. Devils Hole II is located on a disjunct 16 - hectacre (40 acre) portion of Death Valley National Park, owned and managed by the National Park Service. Additionally, it is surrounded by Ash Meadows National Wildlife Refuge, managed by the US Fish and Wildlife Service, and the Ash Meadows Area of Critical Environmental Concern (ACEC), managed by the Bureau of Land Management.	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
1121DCD3ECCD53B58A4B712A8A50EF2E.taxon	description	Figs 3 A, B, 4, 5, 6, 7, 8, 9, 10	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
1121DCD3ECCD53B58A4B712A8A50EF2E.taxon	etymology	Etymology. The specific epithet plutonia is the feminine form of the Latin Pluto and the Ancient Greek Πλούτων (Pluton), the god of the Underworld. Pluto’s Gates or ploutonion were shrines erected to Pluto; one of the most famous is the shrine at Hierapolis, commonly called the “ Gateway to the Underworld. ” This epithet is given both in reference to the hypogean habitat of the species and to play off the nickname of the nearby town of Beatty: “ Gateway to Death Valley. ”	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
1121DCD3ECCD53B58A4B712A8A50EF2E.taxon	diagnosis	Diagnosis. Small-sized, stygomorphic species distinguished from congeners — except members of the H. muerta and H. cretae complex — by the combination of the following characters: eyes absent; antenna 1 longer than antenna 2; pleonites lacking dorsoposterior carinae; maxilla 1 inner plate with 2 apical pappose setae; male uropod 1 inner ramus lacking long curved setae. Differentiated from H. muerta and other members of the H. cretae complex by the combination of the following characters: maxilliped inner plate with 2 apical robust setae; male gnathopod 2 palmar margin with distinct anterior notch; pereopod 7 basis projecting> 1.5 × the length of the ischium, with> 5 posterior setae, all simple, length> 25 % remainder of the pereopod segments; uropod 3 ramus with simple setae; telson with 2 long apical setae.	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
1121DCD3ECCD53B58A4B712A8A50EF2E.taxon	description	Description. Holotype male (Figs 3 A, 4 – 8): 4.20 mm in length. Eyes and integumentary pigment absent (Fig. 3 A). Antennae. Antenna 1 (Fig. 4 A): Approximately 1.2 × length of antenna 2; peduncle segment 1 lacking posterodistal robust setae; primary flagellum with 12 segments, aesthetascs on distal segments, aesthetascs shorter than respective segments, unpaired. Antenna 2 (Fig. 4 B): approximately 30 % body length, gland cone distinct; peduncular segment 5 1.2 × length of segment 4; flagellum with 10 segments. Mouthparts. Mandibles: left mandible (Fig. 4 C): incisor 9 - dentate, lacinia mobilis 5 - dentate, accessory setal row with 2 plumose setae; molar process well-developed, cylindrical, triturative, lacking seta. Right mandible (Fig. 4 D): incisor 5 - dentate, lacinia mobilis bifurcate, lobes with numerous fine dentations; accessory setae row with 2 plumose setae; molar similar in form to left mandible. Upper lip (Fig. 5 A): rounded, apical margin of labrum with numerous setules. Lower lip (Fig. 5 B): inner lobes indistinct, outer margin of inner and outer lobes covered in setules; face of lip covered in pubescent setules. Maxilla 1 (Fig. 5 C): inner plate shorter than outer plate, with 2 apical pappose setae, and fine pubescent setules covering the entire plate; outer plate with 9 apical serrate setae, pubescent setules sparse and decreasing laterally and proximally; palp one-segmented, vestigial, 20 % length of outer plate, tapering distally, with pubescent setules, palp emerges at slightly over half the length of the outer plate. Maxilla 2 (Fig. 5 D): both inner and outer plates covered in pubescent setules; outer plate subequal in length to inner plate, with numerous apical setae; inner plate narrowing slightly distally with numerous apical setae and 2 pappose facial setae. Maxilliped (Fig. 5 E): inner plate shorter than outer plate with 2 unarmed cuspidate setae along apical margin, surface of plate covered in pubescent setules; outer plate with numerous setae, lacking pubescent setules; palp 4 – segmented, second and third segments with numerous marginal, and submarginal setae; dactylus surface lacking comb-scales, nail not elongate. Gnathopods. Gnathopod 1 (Fig. 6 A): coxal plate with 5 short apical setae; basis narrowing proximally, distoposterior surface of segment lacking comb-scales; ischium with a posterior seta; merus with 3 posterior setae, distoposterior surface of segment with sparse comb-scales; carpus subequal in length to propodus, with cluster of posterior serrulate setae; propodus 1.4 × longer than broad with 4 inner medial serrulate setae, anterodistal corner with tuft of setae, comb-scales present along posterior margin; palm straight to slightly convex, with 5 – 9 setae on inner / outer margins; defining angle straight with 2 robust setae; dactylus with plumose seta on outer margin and an inner seta, surface with sparse comb-scales. Gnathopod 2 (Fig. 6 B): coxal plate with 8 short apical setae; basis narrowing proximally with 2 posterior setae; ischium with 2 posterior setae; merus with 4 posterior setae, distoposterior surface of segment lacking comb-scales; carpus 33 % length of propodus, with 2 anterior setae, posterior margin lobate, 40 % breadth of segment, lacking comb-scales; propodus enlarged, powerful, 1.2 × longer than broad, with tuft of anterodistal setae, posterior setae absent; palm straight, irregular with strong anterior notch, palm with 14 inner and 15 outer robust setae; defining angle expanded, projecting past carpus posterior lobe, with 3 robust setae arranged around notch where tip of dactylus rests, comb-scales extend to base of defining angle; dactylus with plumose seta on outer margin placed medially and 2 inner setae. Pereopods. Pereopod 3 (Fig. 7 A): coxal plate with 6 short apical setae, plate not excavated posteroproximally; basis much longer than coxal plate with a posterior seta; merus 1.3 × longer than carpus; carpus 75 % length of propodus; dactylus 50 % length of propodus, with plumose seta placed proximally on outer margin and 2 setae inserted adjacent to base of nail. Pereopod 4 (Fig. 7 B): coxal plate with 6 short apical setae, plate excavated posteroproximally; basis much longer than coxal plate with posterior seta; merus 1.3 × longer than carpus; carpus 75 % length of propodus; dactylus 50 % length of propodus, setation as in pereopod 3. Pereopod 5 (Fig. 7 C): coxal plate large, bilobate, anterior / posterior lobes both with 2 setae each; basis posterior margin weakly convex, with 8 short setae, posterodistal corner convex, anterior margin with 6 robust setae; merus subequal in length to carpus; carpus 80 % length of propodus, dactylus 50 % length of propodus, with plumose seta placed proximally on posterior margin and 2 setae inserted adjacent to base of nail. Pereopod 6 (Fig. 7 D): coxal plate large, bilobate, with produced posterior lobe; basis posterior margin weakly convex, with 10 shallow serrations paired with short setae, posterodistal corner weakly convex, anterior margin with 6 robust setae; merus subequal in length to carpus; carpus 75 % length of propodus; dactylus 35 % length of propodus, setation as in pereopod 5. Pereopod 7 (Fig. 7 E): coxal plate diminutive, lobes indistinct; basis posterior margin convex, projecting 2.0 × past the ischium, with 6 shallow serrations paired with short setae extending to start of posterodistal corner, robust setae absent, posterodistal corner straight, anterior margin with 9 robust setae, basis length 33 % remainder of pereopod segments; merus 80 % length of carpus; carpus 75 % length of propodus; dactylus 25 % length of propodus, setation like pereopods 5 and 6. Gills. Coxal gills present on somites 2 – 7, sternal gills present on somites 3 – 6 (Figs 6 B, 7 A – E). Pleon. Pleosome somites lacking dorsoposterior carinae. Epimera (Fig. 8 A): first epimeron ventral margin unarmed, distoposterior corner not produced, posterior margin with a single seta; second and third epimera like first in form, each with a posterior seta placed more medially. Pleopods (Fig. 8 B): peduncle of pleopod 1 60 % length of rami, with 2 coupling hooks, lacking setae; outer and inner rami with 5 and 9 segments respectively. Pleopod 2 peduncle similar to first, with 2 coupling hooks; outer and inner rami with 5, 8 segments respectively. Pleopod 3 peduncle similar to first / second, with 2 coupling hooks; outer and inner rami with 4 and 7 segments respectively. Urosome. Somites free, bare dorsally. Uropod 1 (Fig. 8 C): peduncle 1.5 × length of inner ramus with 5 outer robust setae and an inner seta; rami narrowing slightly distally, outer ramus with 2 marginal robust setae, and 5 apical robust setae; inner ramus 90 % length of outer ramus, with 1 marginal robust seta, and 6 apical robust setae. Uropod 2 (Fig. 8 D): peduncle 90 % length of inner ramus with 1 inner seta and 3 outer robust setae; rami narrowing weakly distally, outer ramus with 2 marginal robust setae, and 5 apical robust setae; inner ramus 1.1 × length of outer ramus, with 1 marginal robust seta, and 6 apical robust setae. Uropod 3 (Fig. 8 E): diminutive, uniramous; peduncle 1.1 × length of ramus, with 2 robust setae; ramus with 3 setae and a robust seta. Telson (Fig. 8 F): fleshy, rounded, not narrowing distally, as long as broad, with 2 unpaired distal setae (one of which with small accessory seta, perhaps regenerated?), 2 triplets of submarginal plumose setae flanking outer margins, apical margin produced, appearing beveled. Female (Figs 3 B, 9, 10): Allotype, USNM 1694151, 3.25 mm in length. Differing from male in presence of weaker gnathopods with weaker carpals / propodi, and minor differences in uropod and telson setation. Structures not described below as in male. Gnathopods. Gnathopod 1 (Fig. 11 A): coxal plate with 5 short apical setae, basis narrowing proximally, lacking marginal posterior setae; ischium with 1 posterior seta; merus with 3 posterior setae, distoposterior surface of segment with sparse comb-scales; carpus 90 % length of propodus, with 2 distal setae and cluster of posterior serrulate setae, posterior surface of segment lacking comb-scales; propodus 2.3 × longer than broad with 4 inner medial serrulate setae, anterodistal corner with tuft of setae, comb-scales present along posterior margin; palm straight with 5 – 8 setae on inner / outer margins; defining angle straight with 2 robust setae; dactylus with plumose seta on outer margin, and 3 inner marginal setae, surface lacking comb-scales. Gnathopod 2 (Fig. 11 B): coxal plate with 5 short apical setae, basis narrowing proximally, lacking marginal posterior setae; ischium with 1 posterior seta; merus with 2 posterior setae, distoposterior surface of segment with sparse comb-scales; carpus 75 % length of propodus, posterior margin weakly lobate, lacking comb-scales; propodus 1.6 × longer than broad, with 2 inner medial setae, anterodistal corner with tuft of setae, comb-scales present along both anterior and posterior margins; palm straight with 3 – 4 setae on inner / outer margins; defining angle with 2 robust setae; dactylus with plumose seta on outer margin, and 3 inner marginal setae, surface covered in comb-scales. Brood plates. Large setaceous brood plates present on somites 2 – 5, decreasing in size posteriorly (Fig. 11 B). Urosome. Somites free, bare dorsally. Uropod 1 (Fig. 12 A): peduncle 1.3 × length of outer ramus with 3 outer robust setae and an inner robust seta; rami narrowing slightly distally, outer ramus with 3 marginal robust setae, and 4 apical robust setae; inner ramus 90 % of outer ramus with 5 apical robust setae, lacking marginal robust setae. Uropod 2 (Fig. 12 B): peduncle subequal to rami, with 1 inner robust seta and 3 outer robust setae; rami not narrowing distally, outer ramus with 1 marginal robust seta, and 5 apical robust setae; inner ramus subequal in length to outer ramus, with identical setation. Uropod 3 (Fig. 12 C): diminutive, uniramous; peduncle 80 % length of ramus, with 3 robust setae and a seta; ramus with 2 setae and a robust seta. Telson (Fig. 12 F): fleshy, rounded, not narrowing distally, as long as broad, with 2 unpaired distal setae, 2 pairs of submarginal plumose setae flanking outer margins, apical margin produced, appearing beveled.	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
1121DCD3ECCD53B58A4B712A8A50EF2E.taxon	distribution	Distribution and ecology. Hyalella plutonia sp. nov. is known only from its type locality, an unnamed rheocrene spring which emerges approximately 45 m west of Highway 95, ~ 0.7 km north of where the highway intersects with Oleo Road. Little is known about either the ecology of H. plutonia sp. nov. or the spring which it inhabits. The spring is shallow and silty, emerging near some Fremont cottonwood (Populus fremontii) and flowing through primarily broad-leaved cattail (Typha latifolia) and yerba mansa (Anemopsis californica). This spring occurs on land owned and managed by the Nevada Department of Transportation (NDOT) and lies 45 m from the edge of Hwy 95. The Federal Highway Administration (FHA) and NDOT are planning to expand and redesignate Hwy 95 to Interstate 11 through this area, which will involve updating the two-lane highway to a separated four-lane interstate. Additionally, groundwater withdrawal for the town of Beatty, and proposed and current gold and lithium mines in the immediate area, pose a substantial risk to the continued existence of the type locality spring and H. plutonia sp. nov. The type locality spring occurs near the edge of private property where a couple of additional springs occur on the west side of Hwy 95; however, surveys were not conducted on this private property. The second author has surveyed over 20 additional springs in Oasis Valley, on both private and public land, but no other populations of stygobitic hyalellid amphipods have been found; only numerous populations of epigean hyalellid amphipods have been found. Hyalella plutonia sp. nov. co-occurs with the endemic Oasis Valley springsnail (Pyrgulopsis micrococcus) and Amargosa toad (Anaxyrus nelsoni), which were found during a survey of the spring.	en	Cannizzaro, Andrew G., Lange, Corey J., Berg, David J. (2025): Gateways to the underworld: molecular phylogenetic analyses identify patterns of groundwater fauna and two new species of hypogean Hyalella Smith, 1874 (Amphipoda, Hyalellidae) from the northern Mojave Desert. Subterranean Biology 54: 35-68, DOI: 10.3897/subtbiol.54.168846
