Physotarsus truncatus Zhaurova

Zhaurova, Kira & Wharton, Robert, 2009, A revision of Physotarsus Townes (Hymenoptera: Ichneumonidae: Ctenopelmatinae), with description of 18 new species, Zootaxa 2207, pp. 1-52 : 47-49

Physotarsus truncatus Zhaurova , n. sp. ( Figs 57–60 )

Diagnosis. Lateral ocelli separated by 1.2–1.5X their widest diameter from each other and about twice their widest diameter from eye margin. Antenna with 36–38 flagellomeres. Pronotum glabrous medially around and below lateral groove, punctate anterolaterally and dorsolaterally. Mesoscutum shiny, very sparsely punctate on anterior 0.4. T1 about 1.7–1.9X as long as broad. Head yellow with black stripe on vertex and frons; occiput black. Mesosoma largely black laterally, mesoscutum largely black with irregular yellow spot medially, mesosoma otherwise largely yellow dorsally ( Fig. 60 ). T1 yellow basally with a black spot laterally on each side covering posterior 0.5–0.7; remaining tergites mostly orange to light brown. Hind femur, tibia, tarsomeres and pretarsus uniformly orange. Fore wing entirely hyaline.

Physotarsus truncatus is one of several species with a black and yellow mesosoma, a distinctly punctate mesopleuron, and a sparsely to impunctate mesoscutum. It is nearly identical to P. c o rd a t u s and P. emarginatus , but the mesoscutum and mesopleuron are more extensively black in P. truncatus .

Description. Female: Body ( Fig. 57 ) 4.8–6.0 mm, fore wing 4.5–4.8 mm. Head ( Fig. 58 ): Clypeal margin widely subtruncate laterally, with thick, rounded central lobe. Clypeus about 2.4X as wide as long, divided medially by shallow transverse depression. Face densely covered with very short setae; setae longer, less dense on clypeus. Anterior tentorial pits elongate and upcurved laterally. Malar space 0.5–0.6X width of mandibular base. Face twice as broad as long, slightly protruding in profile, face sparsely punctate laterally, more densely punctate medially. Interantennal area flat, area immediately behind antennae weakly concave laterally, turning convex before reaching ocelli. Anterior margin of torulus situated at about 0.7 of eye height. Interantennal distance greater than distance between lateral ocelli. Widest diameter of torulus 1.4–1.6X widest diameter of median ocellus. Lateral ocelli separated by 1.2–1.5X their widest diameter from each other and about twice their widest diameter from eye margin. Area between lateral ocelli slightly depressed; area immediately behind ocelli not sharply declivitous. Antenna with 36-38 flagellomeres; first flagellomere 5.8– 7.5X longer than wide, 1.3X widest transverse diameter of eye, second flagellomere 0.4–0.5X length of first. Occipital carina present on ventral 0.6–0.7 of head. Mesosoma: Anterior margin of pronotum medially slightly emarginate, laterally rounded and upcurved. Lateral groove of pronotum well-developed, weakly sculptured, present at least on dorsal 0.6, usually complete to punctate-rugulose posterior margin. Pronotum glabrous medially around and below lateral groove, polished to very sparsely punctate immediately laterad lateral groove, punctate anterolaterally, and dorsolaterally. Mesoscutum shiny, very sparsely punctate on anterior 0.4 ( Fig. 61 ). Epicnemial carina parallels anterior margin of mesopleuron. Mesopleuron quite densely punctate ventrally. Metapleuron evenly, densely setose. Propodeum without carinae; impunctate and glabrous medially, moderately punctate and pubescence laterally. Tarsal claws simple. Fore wing stigma narrow; Rs+2r arising from basal 0.3–0.4 of stigma; marginal cell about 3.1–3.2X longer than wide; 2rs-m 1.3–1.8X longer than abscissa of M between 2rs-m and 2m-cu; Cu1a about 0.6X length of 2cu-a; cu-a interstitial relative to Rs&M. Hind wing M+Cu bowed to strongly bowed; basal abscissa of Rs 1.1X longer than rs-m; 1st abscissa of Cu1 0.8–1.3X longer than cu-a. Metasoma: T1 about 1.7–1.9X as long as broad; surface in profile flat basally, weakly convex posteriorly, dorsal tendon anchored on nearly flat surface; spiracles not protruding; dorsolateral carina extending about half distance to spiracle. Cerci distinct, slightly ovate, barely protruding.

Male: Subgenital plate ( Fig. 59 ) with wide, deep, truncate median incision, its margin even. Aedeagal margin not toothed. Fore wing 2rs-m 1.1X longer than abscissa of M between 2rs-m and 2m-cu; cu-a weakly antefurcal; otherwise similar to female.

Color. Head yellow with broad black stripe on vertex and frons usually extending as narrow line to dorsal tubercle on face; occiput black. Antenna brown at base, gradually becoming orange medially to bright pale orange subapically, dark brown apically, darker dorsally than ventrally, pale flagellomeres numerous, but number quite variable. Mesosoma largely black laterally, mesoscutum black with moderately large, irregular yellow spot medially ( Fig. 60 ) and rarely with yellow spot or narrow line along anterolateral margin, mesosoma otherwise largely yellow dorsally; anterior margin of propodeum usually black, propodeum with triangular black marking anteriorly on either side of midline. T1 yellow basally with a black spot laterally on each side covering posterior 0.5–0.7; remaining tergites mostly orange to light brown especially laterally, T7– 8 usually extensively yellow laterally. Fore and mid legs bright yellow, tarsomeres often darker yellow or yellow-orange. Hind coxa mostly black with broad yellow stripes dorsally and ventrally; trochanter and trochantellus dark brown to black, except trochantellus pale posteriorly; femur, tibia, tarsomeres, and pretarsus uniformly orange. Cerci dark. Fore wing entirely hyaline.

Material Examined. Holotype ɗ ( AEIC, Type No. 3861): [ USA, Texas] first line of data label: “Fredericksburg” second line: “V.7.1988 Tex.” third line: “H. & M. Townes”. Paratypes: 10 Ψ, same data as holotype except dates ranging 30.iv–v. 19.1988 ( AEIC, TAMU).

Remarks. This species is nearly identical to P. c o rd a t u s, with differences in the male subgenital plate and minor differences in color. Since primary differences are associated with the male, the sole male of P. truncatus was chosen as holotype. Both species were collected from the same locality in central Texas. The species name is Latin, referring to the truncate excavation in the male subgenital plate.

Figures

FIGURES 57 – 60. Physotarsus truncatus n. sp. 57, habitus; 58, face; 59, male genitalia, ventral view; 60, head and mesonotum, Ψ, dorsal view.

FIGURES 61 – 64. Habitus and face. 61 – 62, Physotarsus varicornis; 61, habitus; 62, face. 63 – 64, P. j a m e s i n. sp.; 63, habitus; 64, face.