Camarochilus Harris, 1930

Weirauch, Christiane, Forero, Dimitri & Schuh, Randall T., 2020, Taxonomic revision of Camarochilus Harris (Hemiptera: Pachynomidae), American Museum Novitates 2020 (3959), pp. 1-32 : 5-9

Camarochilus Harris, 1930

Figures 1–7 , table 1

TYPE SPECIES: Camarochilus americanus Harris, 1930 . By original designation.

REVISED DIAGNOSIS (figs. 1–6): Recognized among genera of Pachynomidae by the absence of ocelli, corium and membrane separated by a straight line, trichobothria on abdominal mediosternites 3–8 and the pygophore, medium to large body size in males (6.8–9.8 mm), and male genitalic characters including basal protuberances dorsally on the pygophore and the pygophore that range from symmetrical to strongly asymmetrical in different species. Closest in appearance to the three Old World genera Camarochiloides , Pachynomus , and Punctius , but differentiated by second labial segment about half as long as third (subequal in Camarochiloides and Punctius ), the lateral margin of the pronotum slightly concave (convex in the other three genera), the sculpture of the pronotum with the anterior lobe smooth and the posterior rugose (both rugose in Camarochiloides , both glabrous in Pachynomus , and both finely rugose in Punctius ), the metapleuron longer than high (as long as high in Camarochiloides and Punctius ), the corium with six or seven longitudinal rows of punctures (six in Camarochiloides , four or five elevated rows of granules in Punctius , and two in Pachynomus ), the line between the corium and membrane oblique (transverse in Pachynomus ), and the absence of numerous freeending veins in the membrane (present in Pachynomus ).

REDESCRIPTION: Male: Total length between 6.8–9.8 mm, elongate ovoid with ratio total length to corium width 2.6–3.5, macropterous, hemelytron reaching or surpassing apex of abdomen. COLORATION: Ranging from dark brown with pale yellow marks on connexiva and bases of femora to combinations of castaneous, brown, and pale yellow, with or without pale yellow mark at base of membrane, and veins concolorous with remainder of membrane, slightly lighter, or with contrasting pale yellow coloration. SURFACE AND VESTITURE: Body surface dull to moderately shining, thoracic pleura rugose, labium and legs shiny. Body, antenna, labium, and legs with sparse covering of long setae, setation denser on distal pseudosegment of pedicel and antennal flagellomeres, ventral surfaces of forefemur and foretibia with rows of short and stout spinelike setae, interspersed with long, erect, and moderately stout setae. Small fossula spongiosa on tip of foretibia. Abdominal mediosternites 3–8 laterally with one pair of trichobothria, in submedian position on mediosternite 3 and more laterad on each subsequent segment, trichobothrium on segment 8 at level of trichobothrium 6, trichobothrium 9 dorsolaterally on pygophore (fig. 4H). STRUCTURE: Head moderately elongate, between 1.2 and 1.7× as long as wide, ratio head width to synthlipsis ~2.7–~4.3, with larger value indicating bigger eyes, reniform or globular in lateral view, dorsal eye margin not or barely reaching or surpassing dorsal head surface. Antenna with scape short, slightly curved, reaching or barely surpassing apex of head (fig. 3), (subdivided) pedicel more slender than scape, about as long as combined flagellomeres, flagellomeres slender. Labium (fig. 4B) stout and curved, reaching or slightly surpassing forecoxa, first segment triangular and stout, second about half as long as third, third with width decreasing toward apex, fourth segment almost as long as third, tapering. Thorax lateral margin of pronotum straight or slightly concave, with rounded humeral angle, with distinct anterior collar, smooth calli occupying entirety of lobe, 5–8× longer than posterior lobe (at midline), longitudinal sulcus well developed, with or without sinuous rugosity, posterior lobe extremely narrow to moderately wide at midline, length greater at humeral angle, separated from anterior lobe by more or less deeply imprinted, slightly curved transverse sulcus, sulcus with more or less distinct rugosity, finely or coarsely punctate or rugose, posterior margin concavely excavated, leaving mesoscutum medially exposed; scutellum with anterolateral calli, median sulcus of variable depth, flattened apical area, and blunt, slightly knob shaped, slender, or acute tip. Forewings macropterous, corium with clavus, endocorium, and exocorium well developed, medial fracture long, costal fracture absent, with pitlike punctures along veins on clavus and corium (total of six or seven rows), membrane with two (e.g., fig. 2, C. tenuis ) or three (fig. 1, C. globosus , n. sp.) closed cells, the two cells present in all species formed by M and Cu (anterior) and Cu and An1 (posterior), third cell by R and M; MCu cell as wide as or slightly wider than CuAn1 cell (figs. 1, 2). Legs with fore- and middle trochanters ventrally with spinelike setae apically; forefemur greatly swollen, flattened ventrally, anteroventrally with band of spinelike setae consisting of 2–3 adjacent rows, middle femur slender, ventrally with one band of spinelike setae along anterior margin consisting of 2 rows, and one row along posterior margin, hind femur slender, unarmed; fore- and middle tibiae slender, slightly curved, ventrally with single row of spinelike setae interspersed with setae, with small fossula spongiosa, slightly smaller on middle than on foretibia, hind tibia unarmed. Abdomen with spiracles on mediosternites 3–7 ventrad of ventral connexival suture, pairs of trichobothria on mediosternites 3–8, close to midline on segment 3 and gradually more lateral on subsequent segments. Genitalia with pygophore and parameres symmetrical or almost so to strongly asymmetrical, pygophore with anterolateral protuberances, parameres inserted in posterior half of pygophore, with blade-shaped distal portion of parameres pointing mediad and crossed, trichobothrium on dorsolateral margin of pygophore.

Female: Similar to male in coloration, body shape, and size, macropterous or submacropterous. Genitalia as in figure 5K, L, with clearly separated mediotergites 9 and 10, flanked laterally by paratergite 9, platelike gonocoxa 8, hook-shaped apices of gonapophyses 8 and 9 visible even when ovipositor is almost closed, and gonplacs visible externally as horizontally ovoid sclerites ventral to tergite 10.

DISCUSSION: Harris (1930) created Camarochilus as a subgenus of Pachynomus and differentiated it from the nominal subgenus based on the following characters: the sides of the pronotum constricted (evenly convex in Pachynomus and Punctius ); hemelytra longer with more extensive corium, the apex of which is less transverse (hemelytron does not surpass tip of abdomen, corium shorter and with wider angle); metapleuron flat and longer than high (fig. 4C); and mid and hind leg with tarsomeres 2 and 3 subequal (fig. 4G). We add a character that describes the sculpture of the pronotum to the diagnoses (sculpture of the pronotum with the anterior lobe smooth and the posterior rugose) and that we believe is diagnostic at the genus level, and we follow Chen et al. (2019) in also using the length of the second and third labial segments as part of the diagnosis.

Camarochilus is part of the Pachynominae that are diagnosed, among other characters, by the lack of ocelli (present in Aphelonotinae ) and by corium and membrane separated along a straight line (sinuous in Aphelonotinae ). The arrangement of abdominal trichobothria is diagnostic for the two subfamilies, with Pachynominae possessing pregenital abdominal trichobothria on segments 3 to 8 and Aphelonotinae having trichobothria only on segments 6, 7, and 8. Carayon and Villiers (1968) also indicated that the lateral margin of the pygophore in Pachynominae is ornamented with two protuberances that carry denticles, but did not illustrate them. We show below that these denticles provide excellent species-level diagnostic characters within Camarochilus in terms of size, degree of asymmetry, and ornamentation. We have examined one male specimen of Punctius alutaceus (Stål) where the protuberances are small, symmetrical, and ornamented with a few denticles. Future research on Old World Pachynomidae should document the pygophore protuberances to evaluate whether they also provide species-diagnostic characters for Pachynomus and Punctius . According to Carayon and Villiers (1968), Camarochilus is differentiated from the two Old World genera of Pachynominae by the absence of a costal fracture (present in Pachynomus and faint in Punctius ) and the absence of numerous free-ending veins in the membrane that are characteristic for Pachynomus . The key provided by Chen et al. (2019) now allows for straightforward identification of the four described pachynomine genera.

We examined two specimens of Camarochilus on loan from the BMNH that were both mutilated (e.g., one missing the pygophore) and we were unable to identify these specimens to species. Given current knowledge on species distribution ranges, the fact that both specimens were collected in Guyana , and overall size and coloration, these specimens likely belong to C. americanus . Specimen information details are: GUYANA: Demerara-Mahaica: Phi Cane Grove N. Diamond, 6.62425°N 57.91007°W, 3 m, 12.6.46, H.C. James, 1♂ ( UCR _ ENT 00048875 ) ( BMNH) . East Berbice-Corentyne: New River , 1.9642°N 57.92168°W, 223 m, 03 May 1938, C.A. Hudson, 1⚲ ( UCR _ ENT 00048874 ) ( BMNH) .

Figures

FIGURE 1. Dorsal habitus of Camarochilus spp. Multiple male and female specimens are documented for C. americanus Harris to visualize intraspecific variation; one male and one female specimen (where available) are illustrated for other species. Scale bars = 2 mm.

FIGURE 2. Dorsal habitus of Camarochilus spp. Scale bars = 2 mm.

FIGURE 3. Lateral habitus of Camarochilus spp. Scale bars = 2 mm.