Hexurella ephedra, Monjaraz-Ruedas & Mendez & Hedin, 2023

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 ephedra sp. nov.

Fig. 10

Material examined.

Type material: Holotype: USA - California, San Bernardino Co. • ♂ holotype; Granite Mountains, Deadman's Hills , 0.5 mi behind Amaral Spring , 34.5148, -117.0640; 17 Feb. 2022; R.W. Mendez leg.; RWM 22_018 . Paratype: - San Bernardino Co. • ♀ paratype; Granite Mountains , Deadman's Hills , above Quail Spring, 34.5367, -117.0821; 4 Apr. 2023; R.W. Mendez leg.; RWM 23_032 . Non-type material: - San Bernardino Co. • 3 imm; Granite Mountains , Deadman's Hills , 0.5 mi behind Amaral Spring, 34.5148, -117.0640; 17 Feb. 2022; R.W. Mendez leg.; RWM 22_018. • 2♂, 1♀, 6 imm; Granite Mountains, Deadman’s Hills, above Quail Spring, 34.5367, -117.0821; 4 Apr. 2023; R.W. Mendez leg.; RWM 23_032 .

Diagnosis.

Easily distinguished from sister taxon H. xerica sp. nov. in that the male palpal tibia possesses a comb of 9 thick distal, retromarginal spines (Fig. 10C, E ), a condition unique for the genus. Also, the prolateral surface of male femur I includes a medial patch of 6-10 spines (Fig. 10D, F ).

Description of ♂ holotype

(TAC_000680; Fig. 10A-D ). Total length (including chelicerae) 2.3, cephalothorax and appendages pale cream (in alcohol), eye tubercle with dark pigmentation beneath. Fangs cream colored like cephalothorax, with long, basal to medial hairs projecting inwards. Abdomen slightly darker than cephalothorax, evenly covered with fine hairs. Tergal plates barely lighter than abdomen, anterior rectangular plate covering most of abdominal width, posterior oval plate (difficult to discern) covering ~ 2/3 abdominal width, both plates covered with fine hairs. Carapace (including chelicerae) 1 long, 0.75 wide, sub oval to circular in shape as viewed dorsally, gently rounded in front, slightly indented behind. Low and convex viewed laterally, very sparse fine hairs on lateral posterior margins, without evident cephalic grooves, dorsal pigmentation (in alcohol) mostly lacking. Thoracic groove very shallow, linear, barely pigmented, 0.05. Eyes set on low tubercle, ~ 1/3 width of anterior carapace, offset from anterior carapace edge by distance equal to length of tubercle itself. Anterior lateral eyes ~ 2 × as large as others, themselves ca. equal in size. Anterior eye row procurved, posterior eye row approximately straight. Sternum 0.6 long, 0.5 wide, sparsely covered with hairs concentrated on lateral edges, sternal sigilla not obvious. Labium 0.1 long, 0.2 wide, with forwards-projecting hairs. Endites 0.225 long, 0.2 wide, whitish, and thickened medially, hairbrushes projecting forwards on prolateral edge. Chelicerae 0.3 long, 0.1 wide at base (viewed from above), promargin with four large teeth, microteeth between; retromargin with one basal microtooth. Leg formula 4132. All legs clothed with fine hairs, legs III and IV with more numerous spines on all surfaces, and with conspicuous spines distally. Leg I thickened, with femur 1/3 as deep as long, prolateral surface of femur with medial patch of 6 spines (Fig. 10A ), tibia and metatarsus with three and two ventral spines, respectively. Leg I (prolateral view) total length 2.2 (0.7, 0.3, 0.5, 0.4, 0.3). Palp (prolateral view) total length 1.4 (0.5, 0.2, 0.5,, 0.3). Palp clothed with fine pale hairs and weak spines; tibia thick, cylindrical, two times as long as deep, comb of nine thicker retromarginal spines on distal edge (Fig. 10B ). Abdomen 1.3 long, 0.8 wide, suboval, somewhat flattened. Posterior median spinnerets slightly shorter than anterior laterals, posterior lateral spinnerets tapering and four-segmented. Embolus closely appressed to the conductor (viewed at 10X magnification).

Description of ♀ paratype

(SDSU_TAC000695; Fig. 10H ). Total length (including chelicerae) 4.8, cephalothorax and appendages dirty cream (in alcohol), including legs. Eye tubercle with dark pigmentation beneath. Fangs pale cream, clothed with long, basal hairs projecting inwards. Abdomen very slightly darker than cephalothorax, densely covered with fine hairs. Tergal plates ca. same color but shinier than abdomen, anterior oval plate covering most of abdominal width, posterior oval plate covering ~ 1/3 of abdominal width, both plates with fine hairs. Carapace (including chelicerae) 2.07 long, 1.30 wide, suboval in shape as viewed dorsally, gently rounded in front, slightly invaginated behind. Low and convex viewed laterally; mostly without hairs, a few fine hairs towards lateral middle and posterior margins, without evident cephalic grooves, dorsal pigmentation (in alcohol) mostly lacking. Thoracic groove shallow, linear, slightly pigmented, 0.125. Eyes set on low tubercle, ~ 1/3 width of anterior carapace, offset from anterior carapace edge by distance equal to depth of tubercle itself. Anterior lateral eyes ~ 3 × larger than all others, themselves ca. equal in size. Anterior eye row procurved, posterior eye row approximately straight. Sternum 0.8 long, 0.6 wide, sparsely covered with long hairs, sternal sigilla not obvious. Labium 0.1 long, 0.2 wide, gently rounded along whitish anterior edge, with forwards-projecting hairs. Endites 0.325 long, 0.3 wide, whitish and thickened medially, conspicuous forward-projecting hairbrushes on prolateral edge. Chelicerae 0.5 long, 0.3 wide at base (viewed from above), promargin with three large teeth, microteeth between; retromargin with one basal larger tooth. Leg formula 4132. All legs clothed with fine hairs; legs I and II mostly without dorsal or lateral spines but with ventral spines on tibia and metatarsus; legs III and IV with more numerous spines on all surfaces, and with conspicuous spines distally. Paired tarsal claws with 5-7 microteeth. Leg I (prolateral view) total length 2.5 (0.825, 0.4, 0.5, 0.5, 0.3). Palp (prolateral view) total length 1.6 (0.6, 0.3, 0.3, 0.4), clothed with long hairs, four weak spines on ventral tibia. Abdomen 2.7 long, 1.7 wide, sub oval, somewhat flattened. Posterior median spinnerets slightly shorter than anterior laterals. Posterior lateral spinnerets tapering, four-segmented, third segment slightly longer than others and pseudo-segmented. Spermathecae with medial and lateral receptacles ca. equal length, apparently open-ended; small out-pocketings lateral to receptacles blunt-tipped (Fig. 10H ).

Variation.

Males from Quail Spring have more femur I spines than topotypic males (Fig. 10D, F ), but possess a similar retrolateral palpal comb.

Distribution and natural history.

Known only from the Deadman Hills in the Mojave Desert of southern San Bernardino County, California (Fig. 3 ). Both Amaral and Quail Springs are situated below shallow canyons of rounded, coarse-grain, granitic formations. The plant community on the slopes where the spiders have been found consists mostly of an Ephedra sp. (likely E. viridis Coville.), Amsinckia Lemh. (Fiddlenecks), and seasonal grasses. H. ephedra were primarily collected under very large rocks where erosion washed finer soils away and leaving a matrix of coarse gravel, dried Ephedra sticks, and other miscellaneous organic material. Despite multiple hours spent searching at both locales, only a few specimens were recovered, likely due to the paucity of accessible habitat and instability of the gravel substrate. The remains of a few webs were observed, with a typical Hexurella branching structure. At the type locality small and medium-sized stones revealed no spiders, with only the largest movable rocks having H. ephedra . This area has extremely hot and dry summers and the inhabited area would be in full sun for much of the day. H. ephedra were more successfully targeted above Quail Spring by focusing on rubble piles along the northern faces of the large granitic outcrops. In the most protected corners H. ephedra were flipped under even small stones but were still uncommon. Both adult males from this location were found in female webs.

Etymology.

The name is a noun in apposition referring to the gymnosperm genus Ephedra L. which was found in close association with the species at the two known localities.

Discussion.

Based on shared palpal morphology, seemingly contiguous habitat, and close geographic proximity (~ 2.5 km distant, Fig. 3 ), we hypothesize that the Quail Spring population represents H. ephedra sp. nov. DNA evidence should be collected to further test this hypothesis.

Conservation status.

Currently known only from a single small mountain range, and therefore of conservation concern. Further surveys are needed to understand the full distribution of this species, including from other canyons and springs in the Granite Mountains.

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 10. H. ephedra sp. nov. A live ♂ holotype (SDSU _ TAC 000680) B ♂ holotype (SDSU _ TAC 000680), dorsal view C ♂ palp, retrolateral view, holotype (SDSU _ TAC 000680) D ♂ leg I, prolateral view, holotype (SDSU _ TAC 000680) E ♂ palp, retrolateral view (Quail Spring, RWM 23 _ 032) F ♂ leg I, prolateral view (Quail Spring, RWM 23 _ 032) G live ♀ (Quail Spring, RWM 23 _ 032) H ♀ paratype spermathecae (pencil outline included to show boundaries of medial and lateral receptacles).