Hyalella plutonia Cannizzaro, Lange & Berg, 2025
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publication ID |
https://doi.org/10.3897/subtbiol.54.168846 |
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publication LSID |
lsid:zoobank.org:pub:730DE74C-1DF1-4E65-B6A9-7B1104D72A01 |
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DOI |
https://doi.org/10.5281/zenodo.17676088 |
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persistent identifier |
https://treatment.plazi.org/id/1121DCD3-ECCD-53B5-8A4B-712A8A50EF2E |
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treatment provided by |
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scientific name |
Hyalella plutonia Cannizzaro, Lange & Berg |
| status |
sp. nov. |
Hyalella plutonia Cannizzaro, Lange & Berg sp. nov.
Figs 3 A, B View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10
Material examined.
• Holotype, male 4.20 mm: Unnamed spring, ~ 0.7 km north of Highway 95 and Oleo Rd intersection , Nye County, Nevada, USA ( 37.005118, -116.726843); collector: Corey J. Lange, 14 December 2023; USNM 1694150 About USNM GoogleMaps . • Allotype, female 3.25 mm: same locality and collection data as holotype; USNM 1694151 About USNM GoogleMaps . • Paratype males, n = 2, same locality and collection data as holotype; USNM 1694153 About USNM GoogleMaps . • Paratype females, n = 2, same locality and collection data as holotype; USNM 1694152 About USNM GoogleMaps .
Type locality.
Unnamed spring, ~ 0.7 km north of Highway 95 and Oleo Road intersection (on west side of highway), Oasis Valley, Nye County, Nevada, USA ( 37.005118, -116.726843).
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. ”
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.
Description.
Holotype male (Figs 3 A View Figure 3 , 4 View Figure 4 – 8 View Figure 8 ): 4.20 mm in length. Eyes and integumentary pigment absent (Fig. 3 A View Figure 3 ).
Antennae. Antenna 1 (Fig. 4 A View Figure 4 ): 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 View Figure 4 ): 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 View Figure 4 ): 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 View Figure 4 ): 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 View Figure 5 ): rounded, apical margin of labrum with numerous setules.
Lower lip (Fig. 5 B View Figure 5 ): 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 View Figure 5 ): 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 View Figure 5 ): 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 View Figure 5 ): 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 View Figure 6 ): 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 View Figure 6 ): 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 View Figure 7 ): 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 View Figure 7 ): 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 View Figure 7 ): 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 View Figure 7 ): 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 View Figure 7 ): 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 View Figure 6 , 7 A – E View Figure 7 ).
Pleon. Pleosome somites lacking dorsoposterior carinae.
Epimera (Fig. 8 A View Figure 8 ): 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 View Figure 8 ): 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 View Figure 8 ): 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 View Figure 8 ): 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 View Figure 8 ): diminutive, uniramous; peduncle 1.1 × length of ramus, with 2 robust setae; ramus with 3 setae and a robust seta.
Telson (Fig. 8 F View Figure 8 ): 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 View Figure 3 , 9 View Figure 9 , 10 View Figure 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 View Figure 11 ): 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 View Figure 11 ): 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 View Figure 11 ).
Urosome. Somites free, bare dorsally. Uropod 1 (Fig. 12 A View Figure 12 ): 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 View Figure 12 ): 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 View Figure 12 ): 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 View Figure 12 ): 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.
Variation.
Individuals examined were shown to vary significantly in several morphological characteristics (Table 3 View Table 3 ).
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.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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SubOrder |
Senticaudata |
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InfraOrder |
Talitrida |
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Talitridira |
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SuperFamily |
Hyaloidea |
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