Physotarsus cordatus 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 : 19-21

Physotarsus cordatus Zhaurova , n. sp. ( Figs 23–26 )

Diagnosis. Lateral ocelli separated by 1.3X their widest diameter from each other and about 2.2X their widest diameter from eye margin. Antennae with 36–38 flagellomeres. Pronotum glabrous medially around and below lateral groove, punctate anterolaterally. Mesoscutum shiny, sparsely punctate on anterior 0.4. T1 about twice as long as broad. Head yellow with black median stripe on vertex and usually frons; occiput black. Mesosoma black and yellow dorsally ( Figs 23 , 26 ). T1 yellow basally with black spot laterally on each side between spiracle and posterior margin; metasoma otherwise uniformly orange. Hind femur, tibia, and tarsomeres uniformly orange. Fore wing entirely hyaline.

Physotarsus cordatus is one of several species with a black and yellow mesosoma and a distinctly punctate mesopleuron. It differs from nearly all of these by the absence of dark brown to black markings on T2-6, which are uniformly orange in P. c o rd a t u s. Physotarsus truncatus is nearly identical but is darker, most notably on the mesoscutum which lacks the yellow notaular lines of P. c o rd a t u s.

Description. Female: Body ( Fig. 23 ) 5.6 mm, fore wing 5.3 mm. Head ( Fig. 24 ): Clypeal margin widely subtruncate laterally, with thick, rounded central lobe. Clypeus about 2.8X as wide as long, divided medially by very shallow transverse depression. Face covered with very short setae; setae longer, slightly less dense on clypeus. Anterior tentorial pits elongate and upcurved laterally. Malar space 0.4–0.5X width of mandibular base. Face twice as broad as long, slightly more protruding dorsally than ventrally in profile, 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 1.3X widest diameter of median ocellus. Lateral ocelli separated by 1.3X their widest diameter from each other and about 2.2X their widest diameter from the eye margin. Area between lateral ocelli slightly depressed; area immediately behind ocelli not sharply declivitous. Antennae with 36–38 flagellomeres, first flagellomere 1.3X widest transverse diameter of eye, second flagellomere 0.6X length of first. Occipital carina present on ventral 0.6–0.7 of head. Mesosoma: Anterior margin of pronotum medially emarginate, laterally rounded, slightly upcurved. Lateral groove of pronotum distinctly impressed, usually weakly sculptured, extending over dorsal 0.6. Pronotum glabrous medially around and below lateral groove, punctate anterolaterally. Mesoscutum shiny, sparsely punctate on anterior 0.4 ( Fig. 26 ). Epicnemial carina parallels anterior margin of mesopleuron. Mesopleuron quite densely punctate ventrally. Metapleuron evenly, densely setose. Propodeum without carinae; impunctate and glabrous medially, moderately to densely punctate and pubescent laterally. Tarsal claws simple. Fore wing stigma narrow, roughly 4.5X longer than wide; Rs+2r arising from basal 0.4 of stigma; marginal cell about 3.2X longer than wide; 2rs-m 1.8X longer than abscissa of M between 2rs-m and 2m-cu; Cu1a about 0.4X length of 2cu-a; cu-a interstitial to weakly postfurcal relative to Rs&M. Hind wing M+Cu bowed; basal abscissa of Rs approximately equal length of rs-m; 1st abscissa of Cu1 approximately equal cu-a. Metasoma: T1 about 2.0X 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, weakly but distinctly protruding.

Male: First flagellomere 5.4–5.5X longer than wide. Subgenital plate with wide, deep, truncate median incision, its margin slightly bifurcate ( Fig. 25 ). Aedeagal margin not toothed. Otherwise similar to female in structure and color, but more variable: 2rs-m 1.4–2.4X longer than abscissa of M between 2rs-m and 2m-cu; cu-a weakly antefurcal to weakly postfurcal relative to Rs&M.

Color. Head yellow with broad, black, median longitudinal band on vertex, usually continuing anteriorly to base of antenna, occasionally extending as narrow stripe to dorsal tubercle on face; occiput black. Antenna dark brown at base, gradually becoming orange medially, dark brown to black at apex, darker dorsally than ventrally, pale flagellomeres numerous, but number quite variable. Pronotum, mesopleuron, and metapleuron mostly black, scutellum and all but thin basal margin of propodeum yellow, mesoscutum with varying pattern of black and yellow ( Fig. 26 ). T1 yellow basally with black spot laterally on each side extending from spiracle and posterior margin; metasoma otherwise uniformly orange; cerci usually dark. Hind coxa black and yellow, occasionally with orange, hind femur, tibia, and tarsomeres uniformly orange. Fore wing entirely hyaline.

Material Examined. Holotype ɗ ( AEIC, Type No. 3850): [ USA, Nebraska] first line of data label: “Valentine Refuge” second line: “ VI.4. 72 Nebraska” third line: “H. & M. Townes”. Paratypes: 1 Ψ 5 ɗ 2 sex unknown, same data as holotype except dates ranging 6–8.vi.1972 ( AEIC, TAMU); 1 ɗ [ USA], Texas, Fredricksburg, 5.v.1988 (H&M Townes) ( AEIC).

Remarks. The holotype is not as extensively dark as most of the paratypes, but was chosen because it is in better condition. In the holotype, for example, the black median band on the head is broadly interrupted on the frons, which is mostly yellow.

The species name is derived from Latin for heart, referring to the heart-shaped aedeagus and outline of the subgenital plate. This species is known only from central Texas and north-central Nebraska.

Figures

FIGURES 21 – 24. Habitus, face, and male genitalia. 21 – 22, Physotarsus concavus n. sp.; 21, face; 22, male genitalia, ventral view. 23 – 24, P. cordatus n. sp.; 23, habitus; 24, face.

FIGURES 25 – 28. Physotarsus spp. 25 – 26, P. cordatus n. sp.; 25, male genitalia, ventral view; 26, head and mesonotum, dorsal view. 27 – 28, P. eliethi; 27, habitus; 28, face.