Stegoelmis shepardi sp. nov.

(Figs. 2, 8, 9, 10)

Diagnosis. General dorsal color pattern light grey, with lighter areas being very light and darker areas being not too dark; elytral apices slightly prolonged and dehiscent; protibial cleaning fringe of tomentum as short as first tarsal segment; metatibial cleaning fringe of tomentum long and slender, occupying apical 1/4; row of moderately long hairlike setae on outer margin of paramere with each setae having almost same size and restricted to apical 1/4.

Description. Holotype: male (Figs. 2, 8, 9). Length 4.6 mm, greatest width 1.78 mm. Body (Fig. 2) robust, subparallel; body sparsely covered with fine, short, recumbent and pale setae; dorsal surface covered with punctures with the diameter of eye facets and spaced by two times their diameter; scutellum glabrous; ventral surface covered with punctures one to four times the diameter of eye facets, coarser on sides of prosternum, mesoventrite, sides of metaventrite, hypomeron, and becoming progressively smaller from ventrite I to ventrite V; dorsum and venter covered with plastron.

Head (Fig. 2): With short and deep longitudinal impression between base of antennae. Eyes protuberant, laterally rounded, separated by a distance of 0.38 mm. Antenna with 11 segments, long and slender, first and last segments slightly swollen and twice as long as the remaining segments. Frontclypeal suture present between bases of antennae. Clypeus rectangular, as long as and 1.5 times wider than labrum; anterior margin concave; lateral angles rounded. Labrum rectangular; anterior margin slightly convex; anterolateral angles rounded; row of moderately long pale setae on middle; row of short pale setae on anterior margin. Maxillary palpus with four segments; last segment feebly swollen, shorter than second and third segments combined. Labial palpus with three segments; last segment swollen, as long as the remaining segments combined. Gula narrower than submentum.

Color (Figs. 2): Areas covered with plastron on dorsum and legs: mottled light grey and grayish-brown; forming an inverted Y in light grey on pronotum and a big I in grayish-brown on middle of elytra. Areas covered with plastron on venter: cuticle grayish-brown and opaque. Areas not covered with plastron: cuticle redish-brown and shiny, except eyes (black).

Thorax (Figs. 2): Pronotum (Fig. 2) longer (1. 33 mm) than wider at base (1.22 mm); without carinae; impressions on disc (one deep longitudinal, median, from posterior to anterior margin); gibbosities (two median, one on each side, on basal 2/5; two lateral, on each side, on middlelength); anterolateral angles rounded; concave at middle, extending over base of head; lateral margin almost straight on basal 1/2 and then feebly sinuate, smooth; posterior angles produced, acute; posterior margin with three arches, two broad, one on each side in front of the elytron, and one narrow in front of scutellum. Elytra (Fig. 2) subparallel; longer (3.4 mm) than wide, (maximum width, at apical 1/3, 1.69 mm); humeral angle broadly rounded, tumid; without carinae; posterolateral angles with small acute protuberance, lateral margins smooth; apices rounded, dehiscent; deep striae and punctures; disc with punctures separated by two to four times their diameters, half as wide as intervals between striae. Scutellum (Fig. 2) flat; subrectangular; longer than wide; wider at basal 2/5; anterior margin convex; posterior angle acute. Prosternum with anterior margin sinuate, concave at middle; anterolateral angles rounded; without impressions or carinae. Prosternal process longer (0.54 mm) than wide at middle (0.16 mm); extending beyond anterior coxae; with a narrow, moderately deep median longitudinal impression; narrowed to apex; lateral margin broadly concave, apex truncate. Mesoventrite shorter (0.44 mm) than wide between coxae (0.56 mm); shorter than prosternum; anterior margin concave; posterior margin between mesocoxae convex. Metaventrite with median, longitudinal impression extending until apical 2/5; anterior margin between mesocoxae concave; posterior margin between metacoxae convex; posterior portion in front of metacoxae with transverse arched impression. Legs (Figs. 2, 3) long, robust; pro- and mesocoxae globular; protibiae with two (anterior and internal margins) short fringes of tomentum on apices; mesotibiae with one (internal margin) short fringe of tomentum, as short as first tarsal segment; and metatibiae with one (internal margin) long and slender, occupying apical 1/4; last tarsal segment longer than remaining segments combined; tarsal claws without basal teeth.

Abdomen: Longer (1.99 mm) than wide (maximum width, ventrite I, 1.69 mm). Ventrite I with anterior margin between metacoxae sinuate; without carinae or impressions; disc depressed on anterior 1/2. Ventrite III with rounded posterolateral projection. Ventrite V without posterolateral toothlike projection; posterior margin convex, with short setae.

Male Genitalia (Figs. 8, 9): Paramere (Figs. 8, 9) long, longer than median lobe; in dorsal view (Fig. 8) elongate; external lateral margin almost straight on basal 3/5 and then broadly sinuous; internal lateral margin broadly and feebly convex on basal 2/7 and then broadly concave until middle length; posterior 1/2 feebly, broadly sinuous and feebly turned diagonally to external margin; base broadly rounded; apical 1/9 feebly curved to external margin; row of moderately long hairlike setae occupying apical 1/4, with almost same size among each other; apex slender and rounded; in lateral view (Fig. 9) slightly curved to venter; ventral and dorsal margins parallel on basal 2/7 and then gradually narrowed to apex; basal acute projection on ventral margin; apex subacute. Median lobe (Figs. 8) long, almost tree times the length of basal lobe; in dorsal view (Fig. 8), gradually narrowed to apex; lateral margin straight; apex slender and rounded; in lateral view straight and flattened ventrally until basal 9/10; apical portion expanded ventrally; apex rounded.

Plastron: Completely covering dorsal and ventral surface, except: antennae; eyes; clipeo; labrum; middle of metaventrite; apex of tibiae; tarsus.

Female. Externally similar to male, except for the absence of a long and slender cleaning fringe of tomentum on metatibiae.

Female Genitalia (Fig. 10): Coxites with 1/2 the length of the styli; in dorsal view: slightly longer than wide. Styli elongate; in dorsal view: basal segment narrowed from base until basal 2/3; apex of each basal segment truncate; apical segment narrow, subclavate and with 1/9 the length of the basal segment.

Intraspecific variation. Size (n = 11): length 4.45–4.72 mm, maximun width 1.65 – 1.80 mm. Color: small variation on tonality. Morphology: shape of prosternal process apices vary from truncate to feebly sinuate.

Type locality. Cauamé River, Boa Vista Municipality, Roraima State, Brazil (2º52’06”S, 60º44’24”W).

Type series. Holotype (Male): BRAZIL: Roraima: Boa Vista, Cauamé River, 2°52’06”S, 60°44’24”W, D-Net, A. S. Fernandes & L. Fusari leg., 28/v/2009 (INPA); 1 male, same data (INPA); 1 female, same data (INPA); 1 male, same data (DZRJ); 1 male, same data (NMNH); 1 male, French Guiana: 20 km E of Saint Laurent Du Maroni, M. Snizek leg., 12/viii/2006 (INPA); 1 female, same data (INPA); 2 male, same data (EMEC); 2 female, same data (EMEC).

Habitat. Specimens of S. shepardi sp. nov. were collected on decaying wood debris and leaf packs submerged about 50cm of depth in an unshaded area of Cauamé River.

Etymology. The species epithet ( shepardi) was given after Dr. William D. Shepard for his invaluable help during our studies of Neotropical Elmidae .

Comparative notes. From the known species of Stegoelmis, S. shepardi sp. nov. is closer to S. andersoni, S. crinita Spangler, 1990, S. ennsi Spangler, 1990, S. stictoides, S. ica, S. geayi and S. sticta Spangler, 1990 by having elytral apices not rounded and dehiscent (Fig. 2) (Spangler, 1990).

Stegoelmis shepardi sp. nov. can be distinguished from S. ennsi, S. stictoides, S. ica, S. geayi and S. sticta by the presence of medial dense cleaning fringe of long hairlike setae on metatibiae (Fig. 2) (short and sparse cleaning fringe on metatibiae of those species). Stegoelmis shepardi can be distinguished from S. crinita by the cleaning fringe occupying at least 1/4 of metatibiae (restrict to apical 1/ 8 in S. crinita); can be distinguished from S. andersoni by the general color pattern of dorsum, being light grey (Fig. 2) (dorsum dark grey in S. andersoni), by the length of mesotibial cleaning fringe of hairlike setae, being as long as the first tarsal segment (as long as the first two tarsal segments in S. andersoni) and by the metatibial cleaning fringe of hairlike setae, occupying the apical 1/ 4 of metatibiae (occupying apical 1/2 and being slightly denser and wider in S. andersoni).

Stegoelmis shepardi sp. nov. can be distinguished from all known species of Stegoelmis by the morphology of the male genitalia (Figs. 8, 9): parameres with outer lateral margin slightly sinuate (Fig. 8) (almost straight in S. andersoni, S. stictoides and S. ica); row of setae on outer margin of paramere with each seta having almost the same size and restricted to apical 1/4 (Fig. 8) (row with setae getting longer gradually and occupying apical 1/2).