Anacroneuria barbai sp. nov.

(Figs. 1-6)

http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org: TaxonName:494619

Material examined. Holotype ♂ (CNIN-PLH-1) and 1 paratype ♂ (CNIN-PLP-2). MEXICO: Tabasco, Mpio. Huimanguillo, Ejido Villade Gpe, Cascada Cerro de las Flores, 17°21´39” N, 93°37´29” W, Rta. Malpasito-Carlos A. Madrazo, 26 June 1999, J. Bueno, R. Barba cols.

Adult habitus. Body ground color pale-yellow, but with well-defined brown pigmentation on head, thorax, legs and veins of wings (Fig. 1). Head with brown, cone-shaped pigment pattern between ocelli; lappets unpigmented and indistinct; M-line absent; small brown area posterior to compound eyes clothed with fine setae and scattered bristles; occiput and post-occiput paler than rest of head. Pronotum with narrow, hairy mesal light brown stripe; mediolateral bands brown with scattered rugosities, each band moderately constricted at middle; posterolateral margins more darkly pigmented than rest of pronotal margin, the area densely hirsute (Fig. 2). Fore leg brown and paleyellow, femur pale except well-defined distal encircling brown band; tibiae and tarsi entirely brown, meso- and metathoracic legs similarly pigmented except that tibia is pale medially. Wing membrane amber and veins brown; costal vein transparent and subcosta dark brown (Fig. 1).

Male. Forewing length 13 mm (n=2). Hammer pointed and nipple-like with mediolateral weak emarginations at border of anterior margin (Fig. 3). Ventral: aedeagus apex and base of similar width (Fig. 4, 5); apex rounded at tip and transparent with moderately sized, oval ventral membranous lobes; aedeagus constricted subapically; shoulders as well-sclerotized equilateral triangle impressions. Hooks elongate; space between hooks forming "skeleton key-hole-like" appearance; frontal walls of aedeagal base with longitudinal bristles and short carina forming isosceles triangle-shaped area; a pair of small transparent bulges at center from base of aedeagus (Fig. 4). Lateral: anterior part like forelock with semi rounded border of margin; angular bulge at median area and concave at base (Fig. 5). Dorsal: apical diameter greater than base (Fig. 6); apex a narrow scoop extending forward and connected to keel; keel a longitudinal, sclerotized line at middle that ends in an inverted V-shaped figure; lower section of shoulders with scattered, lightly sclerotized rugosities; shoulders with lateral projections upward and moderately sharp at tip, followed by a constriction downward and widened at crossing point of hooks; aedeagus medially constricted with lateral structures attached over transparent membrane (Fig. 5), irregular ellipse-shaped and acute at poles; distal section of aedeagus wider than medially (Fig. 6).

Female. Unknown.

Larva. Unknown.

Diagnosis. The pigment patterns on head and pronotum (Fig. 2) look similar to a Costa Rican species, A. tornada Stark, 1998, but the male of A. barbai is smaller and the aedeagus is quite distinctive (Figs. 1, 3-5 and Figs. 108-110, in Stark, 1998). Among the Mexican species, A. barbai appears most similar in size and head pigment patterns to A. contrerasi Stark & Kondratieff, 2004 . The aedeagus of A. barbai can be distinguished from others in the genus by the triangular structure of the shoulders in ventral view (Fig. 4), as well as the distinctive keel and the scattered rugosities of the lower part of shoulders in dorsal view (Fig. 6).

Etymology. The species name honors the aquatic entomologist Rafael Barba-Álvarez, who has motivated and supported my study of aquatic insects. He was the collector of most of the Mexican stoneflies that I have examined in the CNIN, including the types of this new species.

Comments. These specimens were initially separated from a large number of adults because of the distinctiveness of their habitus. Additional adults available in the CNIN from Tabasco state were determined, but no more specimens of this species have been found. The aedeagus of the paratype male appeared slightly twisted but conspecific with the holotype.

Heretofore, the Plecoptera material in the CNIN was not organized systematically—I have begun this process. In addition, I am now assigning unique identifiers (catalog numbers) to Plecoptera specimens, staring with the types of A. barbai n. sp. The unique identifier begins with the collection coden (CNIN), followed by PL for Plecoptera, then the first letter of the kind of type of the specimen (holotype, allotype, paratype, etc), and ending with a unique number. Non-type specimens will lack letters used to denote types. Eventually, CNIN will have an on-line database of Plecoptera specimens.