Hexurella uwiiltil, 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

publication ID	https://dx.doi.org/10.3897/zookeys.1167.103463
publication LSID	lsid:zoobank.org:pub:30B24690-6AA8-4998-A79B-5D6D4A0F4E31
persistent identifier	https://treatment.plazi.org/id/D57E0E61-DFF8-4ACC-8442-658F181D3086
taxon LSID	lsid:zoobank.org:act:D57E0E61-DFF8-4ACC-8442-658F181D3086
treatment provided by	ZooKeys by Pensoft
scientific name	Hexurella uwiiltil
status	sp. nov.

Treatment

Hexurella uwiiltil View in CoL sp. nov.

Figs 15 View Figure 15 , 16 View Figure 16

Material examined.

Type material: Holotype: Mexico - Baja California Norte • ♂ holotype; Arroyo Salado , E of Hwy 1, 31.2603, -116.0654; 28 Mar. 2022; M. Hedin, R. Monjarez Ruedas, R.W. Mendez leg.; SDSU_TAC000677 GoogleMaps . Paratype: • ♀ paratype; data as for holotype; SDSU_TAC000678 GoogleMaps ; Non-type material: • 7♀; data as for holotype; MCH 22_041 GoogleMaps .

Diagnosis.

This species differs from all other members of the western clade in that the male femur I includes a patch of 10 prolateral spines (Fig. 15A View Figure 15 ), reminiscent of the femur I morphology found in eastern clade members H. pinea and H. zas sp. nov. (Figs 7 View Figure 7 , 9 View Figure 9 ).

Description of ♂ holotype

(SDSU_TAC000677; Fig. 15 View Figure 15 ). Total length (including chelicerae) 2.7, cephalothorax and appendages pale tan (in alcohol), eye tubercle with dark pigmentation beneath. Fangs colored like cephalothorax, with long, basal hairs projecting inwards. Abdomen mottled dark purple with whitish background, evenly covered with fine hairs, tergal plates barely lighter than abdomen, anterior rectangular plate covering most of abdominal width, posterior oval plate (with posterior indent) covering ~ 2/3 abdominal width, both plates covered with fine hairs. Carapace (including chelicerae) 1.23 long, 0.88 wide, suboval in shape as viewed dorsally, gently rounded in front, slightly indented behind. Carapace low and convex viewed laterally, very sparse fine hairs in ocular region and along carapace edges, without evident cephalic grooves, inward-pointed triangular mottled pigmentation above three front leg coxae. Thoracic groove very shallow, linear, slightly pigmented, 0.1. Eyes set on low tubercle, ~ 1/2 width of anterior carapace, offset from anterior carapace edge by slightly less distance as 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, more hairs on lateral edges, sternal sigilla not obvious. Labium 0.1 long, 0.2 wide, with forwards-projecting hairs. Endites 0.25 long, 0.3 wide, whitish, and thickened medially, forward projecting hairbrushes on prolateral edge. Chelicerae 0.4 long, 0.1 wide at base (viewed from above), promargin with three large teeth, microteeth between; retromargin with three basal microteeth. 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, femur one-third as deep as long, prolateral surface of femur with patch of 10 spines, two spines at femur/patella junction, tibia and metatarsus with three and two ventral spines, respectively (Fig. 15A View Figure 15 ). Leg I (prolateral view) total length 2.6 (0.875, 0.4, 0.5, 0.5, 0.3). Palp (prolateral view) total length 1.7 (0.5, 0.3, 0.5, 0.4). Palp clothed with fine pale hairs and weak spines. Palpal tibia thick, cylindrical, ~ 2 × as long as deep, five thicker distal spines on retromarginal tibia/ tarsus joint. Abdomen 1.5 long, 1.0 wide, suboval, 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. Embolus closely appressed to the conductor (viewed at 10X magnification).

Description of ♀ paratype

(SDSU_TAC000678; Fig. 16A-C View Figure 16 ). Total length (including chelicerae) 5.0, cephalothorax and appendages dirty light brown (in alcohol), eye tubercle with dark pigmentation beneath. Fangs concolorous dusky, clothed with long, basal hairs projecting inwards. Abdomen mottled dark purple with a whitish background, densely covered with fine hairs. Tergal plates lighter than abdomen, anterior oval plate covering most of abdominal width, posterior oval plate covering ~ ½ of abdominal width, both plates with fine hairs. Carapace including chelicerae 2.2 long, 1.6 wide; suboval in shape as viewed dorsally, gently rounded in front, slightly invaginated behind; low and convex viewed laterally; inconspicuous fine hairs in ocular region and along carapace edges, without evident cephalic grooves, mottled pigmentation above three front leg coxae. Thoracic groove shallow, linear, slightly pigmented, 0.2. Eyes set on low tubercle, ~ 1/3 width of anterior carapace, offset from carapace edge by approximately same distance as tubercle length. Anterior lateral eyes ~ 1/3 larger than all others, themselves ca. equal in size. Anterior eye row procurved, posterior eye row approximately straight. Sternum 1.2 long, 0.9 wide, sparsely covered with long hairs, sternal sigilla not obvious. Labium 0.1 long, 0.4 wide, gently rounded along whitish anterior edge, with forwards-projecting hairs. Endites 0.5 long, 0.4 wide, whitish, and thickened medially, conspicuous forward projecting hairbrushes on prolateral edge. Chelicerae 0.7 long, 0.3 wide at base (viewed from above), promargin with three large teeth, microteeth between and basal to last promarginal macrotooth; retromargin with single basal 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 3.9 (1.3, 0.75, 0.8, 0.5, 0.4). Palp (prolateral view) total length 2.2 (0.9, 0.4, 0.4, 0.5), clothed with long hairs, three spines on ventral tibia. Abdomen 2.8 long, 1.9 wide, suboval, somewhat flattened. Posterior median spinnerets are slightly shorter than anterior laterals. Posterior lateral spinnerets tapering, four-segmented, third segment pseudo-segmented and slightly longer than others. Spermathecae with thin medial receptacles slightly longer than lateral receptacles; small pockets lateral to receptacles with nipple-like extensions (Fig. 16C View Figure 16 ).

Variation.

Only a single male is known. We did not dissect and compare spermathecae from other topotypic females, but these non-paratype specimens are like the paratype in body size and markings (e.g., dark abdomens, dark carapace edges, etc.).

Distribution and natural history.

Only known from the type locality, a north-facing ravine in low coastal desert (Fig. 16D, E View Figure 16 ). Females and immatures were common under small to medium-sized rocks and litter along the slope. Vegetation consisted of abundant annual ground covers with shade and litter coming from tall shrubs growing along the drainage, likely Rhamnus crocea Nutt. (Redberry Buckthorn). The microhabitat was like the Hacienda Sinaloa locale, with dry millipede frass making up a considerable amount of the matrix the webs were constructed in. The litter, frass, and rocks overlaid a gravel mixture the spiders could easily retreat into, and at least one male was lost this way.

Etymology.

A noun in apposition which means spider in the Kiliwa language. The Kiliwa are indigenous peoples of northern Baja California, originally inhabiting an area surrounding the Sierra de San Pedro Mártir. The Kiliwa language is in danger of extinction, with fewer than 50 speakers in a recent census. We honor them and their language by naming this species in the same way they named these spiders centuries ago.

Discussion.

Both mitogenomic and nuclear phylogenomic data support Hexurella uwiiltil sp. nov. as sister to H. encina (Figs 1 View Figure 1 , 2 View Figure 2 , 4 View Figure 4 ), also endemic to northern Baja California Norte.

Conservation status.

This species is currently known only from a single locality, with bounding locations for H. encina to the north and south (Fig. 3 View Figure 3 ). More collecting effort is needed to understand the distribution and conservation status of Hexurella uwiiltil sp. nov.