Hentzia alamosa, David B. Richman, 2010

David B. Richman, 2010, A new species and new records of Hentzia (Araneae: Salticidae: Dendryphantinae) from the United States, The Journal of Arachnology 38, pp. 73-78 : 73-75

Hentzia alamosa new species

Figs. 1–10, 17

Type material. — Female holotype, USA: Texas: Cuevas Amarillas, Big Bend Ranch State Park , Presidio County, Texas (29°29ʹ41.5ʺN 104° 0 6ʹ 0 0ʺW, 1094.5 m), 28 March 2004, D.B. Richman, beating cottonwood along wash east of caves, deposited in the collection of Texas A & M Insect Collection ( TAMUIC), College Station , Texas. Male and female paratypes: same data as holotype. Male paratype deposited in TAMUIC ; female paratype deposited in the Florida State Collection of Arthropods, Gainesville, Florida .

Other material. — USA: Texas: 2 females, Ojito Adentro, Big Bend Ranch State Park , Presidio County (29°29ʹ28.8ʺN, 104°0 3ʹ42ʺW, 1162 m), 14 October 2000 ( TAMUIC) and 27 March 2004 (Arthropod Museum, New Mexico State University - NMSU), D.B. Richman. Beating cottonwoods.

Distribution. —Known only from Big Bend area.

Etymology. —The name is taken from the Spanish alamo for cottonwood, the trees on which this species has so far been collected.

Diagnosis. —Males of this species would key out to Hentzia palmarum in Richman (1989), but the females have a very distinctive flattened to normal U-shaped atrium above the bell-like central structure ( Figs. 4, 5, 9, 10). Hentzia palmarum has either two separate openings or these are connected as an upside-down, U-shaped depression ( Figs. 11–15 and Richman (1989, figs. 24, 26).

Females so far collected, with the exception of one from Ojito Adentro (TAMUIC), which had three sets of distinct paired brown spots on the dorsum, lack a pattern on their abdomen except for a few tiny spots and occasionally vague

73 streaks, whereas most H. palmarum females have at least a faint, but distinct, set of blotches and chevrons (see Kaston 1978; Richman 1989). Females of H. alamosa also have all pale legs, whereas in H. palmarum females the front pair is darker than the rest. The male chelicerae ( Figs. 6, 17) differ from those of H. fimbriata , in which the teeth are evenly spaced (Richman 1989, fig. 37), and more closely resembled those of H. palmarum . However, in H. palmarum the retromarginal tooth is usually slightly more proximal than the proximal promarginal tooth (Richman 1989, figs. 18, 19), while in H. alamosa the proximal promarginal and retromarginal teeth are almost exactly in line when viewed ventrally ( Fig. 17). The one male collected also had a very light band on the tip of its abdomen, which has not been seen in H. palmarum . This is the first Hentzia reported from the Chihuhuan Desert, and the type locality is approximately 385 km southwest of the nearest known records for Hentzia palmarum in Edwards County, Texas.

Female. —Female holotype from Presidio County, Texas: Total length 4.2, carapace length 1.9, carapace width 1.6. Ventral spines on first tibiae 2-2-2. Leg formula 1423. Chelicerae with 2 promarginal teeth and one larger retromarginal tooth. Body almost unicolored yellowish, with two dark speckles (4–6 on paratype females) on the dorsum of the abdomen [very faint slanted bands laterally in paratype female from Cuavas Amarillas, and one female from Ojito Adentro had dark brown markings similar to those found on females of Hentzia mitrata (Hentz) (see Richman 1989, fig. 30)]. Chelicerae red-brown, endites lighter red-brown with pale distal portion. Sternum brown anteriorly, fading to yellow toward the posterior. Legs and palpi pale yellow.

Male. —Male allotype (paratype) from Presidio County, Texas. Total length 4.5, carapace length 2.0, carapace width 1.7. Leg formula 1423. General description close to H. palmarum , with 2 promarginal teeth and one larger retromarginal tooth, all acute and the latter almost exactly in line with the proximal promarginal tooth ( Figs. 6, 17). Abdominal pattern distinctive, with light band (appearing as spot) at tip of abdomen. However, as only one male is known this may not be a diagnostic character.

Natural History. —This species seems to be closely associated with tall trees, especially, if not exclusively, cottonwoods ( Fig. 1). Attempts to collect it on associated trees and shrubs along the wash at Cuevas Amarillas on the same date as the types failed, despite numerous attempts. Males are only known from March and females from March and October. Adults may be found (like H. palmarum ) throughout the year.

Remarks. —An illustration by Kaston (1948, fig. 1814) bares some slight resemblance to the epigynum of this species, but resembles the epigynum of H. fimbriata even more closely. On the other hand illustrations of the epigynum of H. palmarum in Peckham & Peckham (1909, plate 42, fig. 1b) and in Chickering (1944, fig. 42), as well as unpublished drawings by Wayne Maddison (see Proszynski 2007), all agree with the illustrations of Richman (1989). It is not certain exactly what species Kaston was actually illustrating, since none of the specimens examined for the revision of the genus (Richman 1989) appeared to match this drawing, which was presumably of a female from Connecticut.