Xenelmis uruzuensis, Manzo, Verónica, 2006

Manzo, Verónica, 2006, A review of the American species of Xenelmis Hinton (Coleoptera: Elmidae), with a new species from Argentina, Zootaxa 1242, pp. 53-68 : 55-57

Xenelmis uruzuensis sp. nov.

( Figs. 1–3 , 17, 18 and 24 )

Diagnosis

This new species can be distinguished from all other known Xenelmis species by the following combination of characters: (1) hind tibia of the male with a row of large granules on inner lateral margin and (2) disc of the first ventrite of male with prominent carina, extending the length of the ventrite.

Description

Holotype male, 2.20 mm long, 1.20 mm wide (at midlength of elytra). Body broadly ovate and convex. Cuticle shiny, dorsum and venter nearly black, antennae and legs dark red.

Head: surface densely microreticulate, with dispersed setae and granules; each side with row of granules extending from base of antennae to near mid­dorsal line on vertex. Frontoclypeal suture straight and deep. Labrum with apical margin feebly arcuate, smooth; margin with setae, setae more than 2/3 as long as labrum. Antennae as long as pronotum, 11­segmented, apical segment longest.

Pronotum: 0.70 mm long, 0.85 mm wide at base, tomentose. Surface microreticulate, with granules, granules as wide as facets of eyes, separated by 1–2 times their diameter, each granule with long seta. Base trisinuate, lateral margin bordered by granules separated by 0.5X times their diameter. Disc with two parallel longitudinal rows of oblong granules, extending from near base, almost reaching apical margin ( Fig. 24 ). Surface between rows without granules, with punctures larger than facet, separated by 2–3 times their diameter. Hypomera tomentose, with granules like those on pronotum. Prosternal process almost as wide as long, quadrate (0.45 mm long, 0.40 mm wide), posterior angles rounded; surface with granules like those on pronotum. Mesosternum shiny with dispersed small granules, as wide as facets, separated by 2–4 times their diameter; with groove for reception of the prosternal process. Metasternum with granules like those on mesosternum and deep punctures, with dispersed short setae.

Elytra: 1.50 mm long, 1.20 mm wide. Lateral margins crenulate; apices feebly conjointly produced and rounded; surface with dispersed setae. Each elytron with seven coarse striae formed by deep, round punctures separated by 0.25X their diameter. Intervals convex, microreticulated; third interval with a feeble row of inconspicuous granules (10–12) extending from near base to 4/5 of elytral length. Intervals 5 and 7 each with a row of granules extending from base to almost apex. Epipleura tomentose, microreticulated, without granules. Scutellum subtriangular, flat, longer than broad; surface smooth.

Abdomen: lateral margins tomentose; all sternites with small granules like those of mesosternum and separated by 2–3 times their diameter. Surface between granules microreticulate. Disc of first ventrite with median longitudinal carina, posterior end of the carina concave and prominent (spoon­like) ( Fig. 18 ).

Legs: coxae, trochanters and femora tomentose, surface with small granules separated by 1–4 times their diameter, with short and dispersed setae. Protibia with feeble row of fine granules on inner lateral margin, a short cleaning fringe on apical third of inner lateral margin. Mesotibia with cleaning fringe and a row of large granules on apical two­thirds of inner lateral margin. Metatibia with apical two­thirds having a row of large granules (more than three times the diameter of those of pronotum) and a cleaning fringe ( Fig. 17 ). All tibiae with dispersed short setae, without tomentum. All tarsi with short apical setae. Claws not modified.

Male genitalia: aedeagus ( Figs. 1 and 2 ) long and moderately broad. Penis elongate, apex constricted and folded; ventral sac well developed in mid area of the penis; basal apophyses very long, apices converging toward midline. Parameres distinctly shorter than penis; phallobase moderately large, shorter than penis, closed.

Female: externally similar to male except as follows: (1) pronotum with area in front of scutellum moderately prominent, (2) first abdominal ventrite without carina, (3) row of teeth on fore tibia very feeble, (4) row of granules on hind tibia small and, (5) body lighter in color. Female genitalia as illustrated in Fig. 3 .

Type data

Holotype male. ARGENTINA. Misiones province, Parque Provincial Urugua­í, Aº Uruzú S 25º 51’ 29” W 54º 10’ 10”, 322 m, 30/XI/2001, Domínguez, Nieto & Orce cols.. Paratypes: 5ɗɗ and 4ΨΨ with same data as holotype; 1ɗ and 1Ψ collected in Misiones province, Aº afluente de Tateto, Paraje María Soledad S 25º 51’ 39” W 53º 58’ 56”, XI/30/ 2001, Domínguez, Nieto & Orce cols. Holotype and paratypes deposited in the collection Instituto — Fundación Miguel Lillo, Tucumán, Argentina

Other specimens

1 larva with same data as holotype and 3 larvae collected in Misiones province; Parque Provincial Urugua­í, 500 m, S 25º 44’ 51” W 54º 03’ 37”, 1/XII/2001, Domínguez, Nieto & Orce cols. All material deposited in the collection Instituto — Fundación Miguel Lillo, Tucumán, Argentina.

Comparative notes

Males of X. uruzuensis can easily be distinguished from all the other species of the genus by the presence of a longitudinal carina along the disc of first abdominal ventrite, and hind tibia of male with a row of large granules on inner lateral margin. According to Hinton (1946) X. uruzuensis should belong to the micros ­group due to the presence of a submedian row of granules on the pronotal disc. Nevertheless a preliminary phylogenetic analysis that included all the species of Xenelmis (Manzo, in prep.) suggests that the groups of species proposed by Hinton are not valid. Additionally, the presence of a pronotal row of granules does not appear to be constant among different specimens of the same species as, for example, in X. laura . Some specimens exhibit the submedian row of pronotal granules while others lack it ( Brown 1970).

Habitat

Xenelmis uruzuensis was collected from three rivers at altitudes ranging from 300 to 400 meters and from a depth of 50 cm. All specimens were found where the substrates consisted of large rocks or gravel, cobbles and boulders. The following elmid genera were found associated with specimens of this species: larvae and adults of Heterelmis , Neoelmis , Macrelmis and Microcylloepus , and larvae of Hexanchorus .

Figures

FIGURES 1 – 16. 1 – 3, Xenelmis uruzuensis sp. nov.: 1, male genitalia, ventral view; 2, lateral view of same; 3, female genitalia. 4 – 5, X. tarsalis (paratype): 4, male genitalia, ventral view; 5, lateral view of same. 6 – 7, X. audax (paratype): 6, male genitalia, ventral view; 7, lateral view of same. 8 – 9, X. comis (paratype): 8, male genitalia, ventral view; 9, lateral view of same. 10, X. rufipes (type): male genitalia, ventral view. 11 – 12, X. leechi (type): 11, male genitalia, ventral view; 12, lateral view of same. 13 – 14, X. marcapata (type): 13, male genitalia, ventral view; 14, lateral view of same. 15, X. laura (paratype): male genitalia, ventral view. 16, X. sandersoni: female genitalia, ventral view. Scale bars = 0.10 mm, Fig. 3 = 0.20 mm.

FIGURES 17 – 26. 17 – 18 and 24, Xenelmis uruzuensis sp. nov. male (type): 17, hind leg; 18, abdomen; 24, pronotum. Figs. 19 – 20, X. audax male (type): 19, hind leg; 20, abdomen. 21, X. tarsalis male: hind leg. 22, X. laura male: hind leg. Fig. 23, X. comis male (type): 23, prosternal process. 25, X. marcapata male: head. 26, X. bufo female (type): head.