Hexurella pinea Gertsch & Platnick, 1979

Monjaraz-Ruedas, Rodrigo, Mendez, Raymond Wyatt & Hedin, Marshal, 2023, Species delimitation, biogeography, and natural history of dwarf funnel web spiders (Mygalomorphae, Hexurellidae, Hexurella) from the United States / Mexico borderlands, ZooKeys 1167, pp. 109-157 : 109

Hexurella pinea Gertsch & Platnick, 1979

Figs 7 , 8

Hexurella pinea Gertsch & Platnick (1979): 28, figs 70-72, 74, 76-80 (Dmf).

Material examined.

Near-type locality material: USA - Arizona, Yavapai Co. • 1♂, 1 imm; Brushy Mtn., W of Skull Valley , SW Grasshopper Spring, 34.5555, -112.7475; 13 Apr. 2022; R.W. Mendez leg.; RWM 22_099 .

Non-type material.

USA - Arizona, Mohave Co. • 1♂, 3 imm; Cerbat Mtns, SW Antelope Springs, Antelope Canyon, NE Mt. Tipton, 35.5962, -114.2039; 6 Apr. 2022; R.W. Mendez leg.; RWM 22_087. - Mohave Co. • 4♂, 1♀, 3 imm; Music Mtns, NW Garnet Mtn., Fox Canyon, 35.8196, -114.0491; 7 Apr. 2022; R.W. Mendez leg.; RWM 22_088.

Diagnosis.

The femur I prolateral surface of male H. pinea includes 6-10 larger spines (with a single exception), differing from populations of H. zas sp. nov. which possess 11 or more long spines.

Variation.

Gertsch and Platnick (1979) illustrate the holotype male femur I prolateral surface with ~ 10 larger spines. A male from just west of the type locality at Brushy Mtn (Fig. 3 ) is similar in condition, possessing nine large spines (Fig. 7A ). Males from the more northern Music Mountains possess a femur I prolateral surface with a range of spine numbers (8, 10, 10, 11; Fig. 7C ), overlapping the condition found in type or Brushy Mtn samples. The Cerbat Mountains are geographically adjacent to the Musics (Fig. 3 ), although separated by lower elevation inhospitable habitats. The single male from the Cerbats only has six large femur I prolateral spines (Fig. 7E ).

Distribution and natural history.

The northernmost known Hexurella species, distributed from the Music Mountains on the Colorado River to the Sierra Prieta near Prescott, at elevations between 1400-1575m (Fig. 3 ). Despite sampling at numerous locales throughout its range, this species has proven to be elusive. The three recent collections have all been from different habitats, and multiple attempts at the type locality have failed to produce specimens. The type series was reportedly collected from "duff of Pinus ponderosa forest ( Gertsch and Platnick 1979)," however, we have been unable to recollect them from this kind of litter. At the Brushy Mountain and Music Mountains locales, webs were constructed in nearly completely inorganic granitic gravels under medium to large-sized rocks along slopes. Dried Quercus sp. or Fendlera rupicola A. Grey (Cliff Fendlerbush) leaves were sometimes incorporated into the webs, but spiders were not found when specifically targeting litter at these locales. The exposed Brushy Mountain locale had sparse vegetation and few trees, while the Music Mountain locale was shaded in a stand of pine-oak forest. At Antelope Springs in the Cerbat Mountains, H. pinea was densest (though still uncommon) under stones in a thick patch of Ephedra sp. above the spring (Fig. 8B ). Quercus sp. and Ptelea trifoliata L. (Common Hoptree) litter had been blown or washed under many of the rocks.

Hexurella pinea males have been the most difficult to collect of the three eastern species. This is likely in part due to the gritty soils seemingly preferred by this species, allowing males not attached to a web to quickly escape into the rapidly collapsing substrate when flipping rocks. At a second locale in the Music Mountains a male was lost because of this; no other individuals were found. Additionally, population densities seem low in H. pinea , comparable to the Mojave species H. ephedra sp. nov. and H. xerica sp. nov. The reduced monsoonal rainfall and cooler winter temperatures throughout the distribution of this species may play a role in keeping populations smaller in this species.

Discussion.

DELINEATE and SPEEDEMON ε = 0.0185 analyses (Table 2 ) recover Cerbats+Musics (North) as a separate species from Brushy Mtn (Central). We here conservatively treat these as conspecific based on overlapping patterns of male femur I spination (Fig. 7 ).

The type locality for H. pinea , "5 mi. west of Prescott" ( Gertsch and Platnick 1979), is in the Sierra Prieta (Fig. 3 ). We have not examined type specimens and have been unable to re-collect specimens from the type locality. The Sierra Prieta range is bordered by the Santa Maria Mountains (including Brushy Mountain) to the west, but habitat here is not perceived as contiguous, with the intervening lower elevation Skull Valley. The Sierra Prieta is bordered by the Bradshaw Mountains to the south, and seemingly connected by Hexurella -appropriate habitat. More sampling in the Sierra Prieta to Bradshaw Mountains region may find a contact zone between H. pinea and H. zas sp. nov.

Suitable habitat sampled west of the Colorado River in southern Nevada and the Virgin Mountains failed to produce Hexurella . However, due to the often-patchy distribution of this genus and the local scarcity of H. pinea (or perhaps other undescribed Hexurella species), more collecting is needed in this area.

Conservation status.

Likely secure in appropriate habitats, although uncommon.

Figures

Figure 3. Map of all collection localities. Phylogeographic lineage names for H. apachea as in text. The unsampled type locality of H. pinea is designated with a special symbol; all other type (or near type) localities were sampled, see text.

Figure 7. H. pinea A ♂ leg I, prolateral view (SDSU _ TAC 000691, Brushy Mtn) B ♂ palp, retrolateral view (SDSU _ TAC 000691, Brushy Mtn) C ♂ leg I, prolateral view (SDSU _ TAC 000689, Music Mtns) D ♂ palp, retrolateral view (SDSU _ TAC 000689, Music Mtns) E ♂ leg I, prolateral view (SDSU _ TAC 000690, Cerbat Mtns) F ♂ palp, retrolateral view (SDSU _ TAC 000690, Cerbat Mtns).

Figure 8. H. pinea A live ♂, Brushy Mtn (RWM 22 _ 099) B habitat, Cerbat Mtns (RWM 22 _ 087).