Variation of Paruroctonus soda sp. nov. from across their range. Top two rows, males; bottom row females; holotype male top left.

Dorsal habitus photographs of Paruroctonus soda sp. nov. holotype male (left) and female (right). Scale bars: 10 mm, silhouettes to scale.

Ventral habitus photographs of Paruroctonus soda sp. nov. holotype male (left) and female (right). Scale bars: 10 mm, silhouettes to scale.

Carapace of Paruroctonus soda sp. nov. holotype male (left) and paratype female (right). Scale bars: 5 mm.

Carapace (upper) and sternopectinal region (lower) of Paruroctonus soda sp. nov. holotype male (left) and female (right). Taken under ultraviolet illumination. Scale bars: 5 mm.

Pedipalp of Paruroctonus soda sp. nov., holotype male (above) and female (below). Macrosetae indicated with open circles (proximal) and closed circles (diagnosis character 4). Carinae abbreviations: retrolateral median (rm), dorsal retrolateral (drl), dorsal median (dm), dorsal prolateral (dpl), ventral retrolateral (vrl), ventral prosubmedian (vps), prolateral ventral (plv), prolateral median (plm). Scale bars: 10 mm.

Illustrations of pedipalp chela of Paruroctonus soda sp. nov. A–D holotype male and E–H female A, E retrolateral B, F prolateral C, G dorsal D, H ventral. Trichobothria indicated with open circles. Scale bars: 5 mm.

Illustrations of pedipalp patella and femur of Paruroctonus soda sp. nov. holotype male (B, C) paratype female (A, D). A dorsal patella B retrolateral patella C ventral patella D dorsal femur. Trichobothria indicated with open circles. Scale bars: 2 mm.

Metasoma of Paruroctonus soda sp. nov. holotype male (above) and female (below); ventral, lateral, and dorsal aspects (top to bottom). Ventral sub-median, ventrolateral, lateral submedian, and dorsolateral macrosetae on segments I-IV indicated with black circles (diagnosis character 3). Carinae abbreviations: Dorsolateral (dl), lateral median (lm), lateral supramedian (lsm), lateral inframedian (lim), ventrolateral (vm), ventral submedian (vs), and ventromedian (vm). Scale bars: 10 mm.

Right hemispermatophore of Paruroctonus soda sp. nov.: anterior aspect (left) and posterior aspect (right). Scale bar: 5 mm.

Soda Lake and the surrounding Carrizo Plain, the type locality of Paruroctonus soda sp. nov. Above, satellite imagery of the central Carrizo Plain taken in June 2019; below, a regional overview taken from the eastern side of the North Basin and facing southwest across the Soda Lake taken in May 2021.

Habitat of Paruroctonus soda sp. nov. in May 2021. Note the dominance of Allenrolfea occidentalis and the soft, exposed clay soil along the lakebed.

Photographs of a typical juvenile Paruroctonus soda sp. nov. (left), and atypical coloration observed in one late instar juvenile female. Not to scale.

Adult female Paruroctonus soda sp. nov. with 51 newly born juveniles.

Photographs of four adult Paruroctonus conclusus sp. nov. illustrating intraspecific variation, holotype male is at top left.

Dorsal habitus of Paruroctonus conclusus sp. nov. holotype male (left) and paratype female (right). Scale bars: 10 mm, silhouettes to scale.

Ventral habitus of Paruroctonus conclusus sp. nov. holotype male (left) and paratype female (right). Scale bars: 10 mm, silhouettes to scale.

Dorsal trunk of Paruroctonus conclusus sp. nov. holotype male (above), paratype female (below). Scale bars: 5 mm.

Carapace and sternopectinal region of Paruroctonus conclusus sp. nov. holotype male (left) and paratype female (right). Shown under ultraviolet illumination. Scale bars: 5 mm.

Pedipalp of Paruroctonus conclusus sp. nov., holotype male (above) and female (below). Trichobothria db and dsb (diagnosis character 8) indicated with closed circles. Carinae abbreviations: retrolateral median (rm), dorsal retrolateral (drl), dorsal median (dm), dorsal prolateral (dpl), ventral retrolateral (vrl), ventral prosubmedian (vps), prolateral ventral (plv), prolateral median (plm). Scale bars: 10 mm.

Illustrations of pedipalp chelae of Paruroctonus conclusus sp. nov. A–D holotype male E–H paratype female A, E retrolateral B, F prolateral C, G dorsal D, H ventral. Trichobothria indicated with open circles. Scale bars: 5 mm.

Illustrations of pedipalp patella and femur of Paruroctonus conclusus sp. nov. Holotype male, dorsal patella A retrolateral patella B ventral patella C dorsal femur D Trichobothria indicated with open circles. Scale bars: 2 mm.

Metasoma of Paruroctonus conclusus sp. nov. male holotype (above) and female (below); ventral, lateral, and dorsal aspects (top to bottom). Ventral sub-median and lateral submedian macrosetae on segments I–IV indicated with black circles (diagnosis character 3). Carinae abbreviations: Dorsolateral (dl), lateral median (lm), lateral supramedian (lsm), lateral inframedian (lim), ventrolateral (vm), ventral submedian (vs), and ventromedian (vm). Scale bars: 10 mm.

Right hemispermatophore of Paruroctonus conclusus sp. nov.: anterior aspect (left) and posterior aspect (right). Scale bar: 5 mm.

Koehn Lake and the surrounding Fremont Valley. Above, satellite imagery of Koehn Lake with the type locality of Paruroctonus conclusus sp. nov. indicated with a star, taken in September 2015. Below, a habitat overview looking north-northeast across Koehn Lake towards the El Paso mountains, taken in July 2021.

Habitat of Paruroctonus conclusus sp. nov. at the type locality, taken in July 2021.

Early instar juvenile (left) and late instar juvenile (right) Paruroctonus conclusus sp. nov. Not to scale.

Distribution overview of the 3 Alkali sink Paruroctonus species: P. soda sp. nov. (red), P. conclusus sp. nov. (green), P. bantai bantai (purple), and P. bantai saratoga (blue). Enlarged map represents the rectangle on the inset map at the top left, shading represents elevation with dark being low and light being high elevations, and lines represent county borders.