Potamocoris sitesi Herrera & Springer

Herrera, Federico & Springer, Monika, 2014, New species of Potamocoris Hungerford (Heteroptera, Potamocoridae) from Costa Rica and a key to the species, Zootaxa 3884 (5), pp. 492-496 : 493-495

Potamocoris sitesi Herrera & Springer , n. sp.

Potamocoris beckeri (misidentification): Herrera & Springer (2012): 66.

Description of holotype, coleopteroid male: Measurements: Body length (from apex of head to apex of hemelytra): 2.61; maximum width of abdomen: 1.40. Maximum length of head (on midline): 0.40; maximum width of head (including eyes): 0.72; width of eye: 0.18; length of eye: 0.20; interocular space at narrowest point: 0.38; interocular space at widest point: 0.43; length of labrum: 0.14; width of labrum: 0.21; maximum length of pronotum (on median line): 0.35; anterior width of pronotum: 0.92; posterior width of pronotum: 1.11; width of pronotum (on mid-portion): 1.03; length of anterolateral projections of pronotum (with respect to anterior margin of pronotum): 0.12; maximum length of scutellum (on midline): 0.46; width of scutellum (on anterior margin): 0.96; length of hemelytral commissure: 1.58; maximum width of hemelytron: 0.67; length of femur I, II, III: 0.52, 0.53, 0.64; maximum width of femur I, II, III: 0.25, 0.15, 0.18; length of tibia I, II, III: 0.38, 0.47,0.74; maximum width of tibia I, II, III: 0.07, 0.09, 0.10; length of tarsi I, II, III: 0.15, 0.31, 0.61; width of tarsi I, II, III: 0.05; 0.04, 0.05. Length of rostrum: 0.34. Length of parameres: 0.20.

General: Oval, elongated, slightly shiny, yellowish brown on dorsal surface with four dark tan spots on posterior half and smaller stains. Hairs clustered mainly on head and along pronotal edges, and hemelytra (Fig. 1.1). Ventrally uniform in color, except lighter on legs and head.

Head: Yellowish brown, shiny, smooth with no punctures; almost two times wider across eyes than along midline, proportion 1.80. Lighter tone bordering rounded mesal margin of eye, which also has a row of conspicuous long, fine hairs, and one seta emerging from center of eye when viewed from the side. Anterior portion of head with two tufts of hairs between anterior margin of eye and anterior margin of head; just below latter, a row of short setae projecting forward. Interocular space at widest point more than two and one-third times width of eye, proportion 2.38; posterior central part of head with minute yellowish spots. Labrum one and one-half times longer than broad, proportion 1.5. At least last segment of antennae visible in dorsal view.

Pronotum: Yellowish brown, more whitish on lateral margins, anterolateral corners, and mid-portion of anterior margin. Pronotum almost three times wider on its mid-portion as its length on midline, proportion 2.94; posterior width one and one-fifth times larger than anterior width, proportion 1.20. Anterior margin nearly straight, curving abruptly behind eye forming a minute notch, then curving smoothly to tip of acute anterolateral corner. The latter overpassing posterior margin of eye when seen in lateral view. Lateral margins smooth, weakly curved, following contour of body, then strongly curving and lengthening beyond posterior margin of pronotum, slightly covering bases of hemelytra. Two more obscure or tan spots near anterior margin and two small black spots diagonal to notches of anterior margin of pronotum. Punctures becoming evident on anterior mid-portion and wrinkles on the anterior flanks. A few thin setae along lateral margins.

Scutellum: Yellowish brown with transverse shallow groove or depression and minute punctures. Scutellum over twice as broad as long, proportion 2.08. Anterior margin weakly arched, covered by posterior margin of pronotum. Lateral borders finely black and strongly arched in posterior portion.

Hemelytra: Yellowish brown with two large dark stains on mid-portion along lateral margin. Small dark spots are more abundant along the posterior half of hemelytra. Intersegmental sutures of metanotum and abdominal tergum I visible through the wing. Length of hemelytral commissure over two and one-quarter times width of hemelytron, proportion 2.35. Embolium whitish yellow with a few fine scattered hairs. Hemelytra with punctures over entire surface; with sparse, short, fine setae. Larger setae from posterior half to end along lateral margins.

Legs: yellowish brown. Fore femora dilated, flattened, two times longer than wide, proportion 2.08; bearing minute, stout spines on internal part of femora. Mid legs with row of short, stout spines on anterior side of femora; patch of setae and longer spines clustered on ventral side; tibia stout with four transverse rows of sturdy spines. Hind legs more elongate than mid legs, with spines barely visible along ventral portion of femur; tibia with two rows of fine, long hairs and a row of sturdy spines at apex, some scattered spines on lateral side; tarsi elongate with two rows of long, fine hairs. Tibiae and tarsi of hind legs forming a curve. All legs bearing two claws.

Underside: Head, prosternum and abdomen yellowish brown, smooth. Rostrum almost reaching posterior margin of prosternum. Prosternum with elevated keel between procoxae, projecting beyond anterior margin of prosternum as acute tip, posterior part of keel evenly rounded; anterior edge straight and finely black. Meso- and metasterna slightly darker with two barely noticeable keels between coxae. Abdomen tan, smooth laterally.

Genitalia: apex of genital operculum with barely visible, rounded prominence; basal plate subtriangular, with rounded apex. Parameres becoming progressively narrower, ending in a sharp needle-like point; sides slightly sinuate; right-angled dorsad near mid-length (Fig. 1.3).

Description of female paratype (macropterous): in general structure very similar to holotype. Only the traits that differ from it are mentioned. Larger in size, body length 2.70, maximum width of abdomen 1.53; maximum length of pronotum (on midline): 0.28; posterior width of pronotum: 1.30; maximum length of scutellum (on median line): 0.61; width of scutellum (on anterior margin): 1.01. Hemelytra complete, with clavus, embolium and corium well defined, venation absent on membrane (Fig. 1.2). Female subgenital plate as shown in Figure 1.4.

Etymology: The new species is named in honour of Prof. Ph.D. Robert W. Sites (Division of Plant Sciences, University of Missouri), for his work with aquatic Hemiptera , especially with the family Naucoridae , which inspired the first author to study the creeping water bugs.

Distribution: Known only from the type locality of the San Carlos River in north-central Costa Rica.

Type locality data: COSTA RICA. Alajuela Province; San Carlos River, 500 m. downstream from the mouth of Quebrada Rueda tributary [10º39’26.98”N, 84º16’35.01”W; 50 m. a.s.l.], Feb. 2001, M. Springer. Taken with a kick-net. Physico-chemical variables of this site were provided by Herrera & Springer (2012).

Location of type: Holotype and one paratype are deposited in the Aquatic Entomology Collection at the Zoological Museum of the University of Costa Rica ( MZUCR), San José, Costa Rica. It is preserved in 70% alcohol. A second female paratype in the California Academy of Sciences ( CAS).

Comparative notes: P. sitesi n. sp. can be distinguished from the South American species Potamocoris nelsoni (Longo et al.) and from Potamocoris kleerekoperi (Hungerford) by its size, which does not overlap with these two species. It also differs from Potamocoris usingeri (De Carlo) by having the interocular region and pronotum without peculiar pink spots. In addition, its interocular width with respect to the width of the eye is smaller than that of the other two species, the proportion being 2.38. More importantly, the parameres are constricted at the apex and ending in a needle-like point. From the Mesoamerican species, P. sitesi differs from P. beckeri by not having a notch at the tip of the subgenital plate and from P. i s b i r u differs by not having thick fringes of setae on the margins of the head and pronotum.