Xestoblatta Hebard, 1916

Vélez-Bravo, Andrés & Daza, Juan M., 2021, Molecular systematics and genital morphology of the Neotropical cockroaches from the genus Xestoblatta (Blattellidae), Zootaxa 5057 (3), pp. 301-328 : 318-320

Xestoblatta Hebard, 1916 (sensu stricto)

( Figs 5A–J )

Type species: Xestoblatta carrikeri Hebard 1916 , 42(4): 374.

Diagnosis. Adults of Xestoblatta (sensu stricto) can be distinguished by the presence of the following combination of characters: tergal modification on abdominal segment VII, as a central deep pit or a shallow depression. In some lineages the tergal modification on abdominal segment VII partially covered by the projection of posterior margin of segment V or uncover. Posterior margin of segment VI usually borders the anterior margin of the depression or pit. Hind wings pigmented and with ulnar vein with less than six branches. Some branches do not reach the posterior margin of the wing. Male genitalia with subregion R1v extending anteriorly to cover part of the R 1t + R2 complex. R2i with two projections, proximal projection shorter and thinner than the distal one. Distal one generally, with multiple short digitiform projections with spiniform apexes. Its species can be differentiated from similar species of Sinatablatta gen.n. by the shape of tergal modification. The species of Sinatablatta gen.n. have the tergal modification on abdominal segment VII as a deep transverse groove covering almost three quarters of its width.

Description. Species of medium size (15–18 mm ♂, 15–19 mm ♀) with body and legs pale yellow. Pronotum and tegmina glossy in appearance, light chestnut or golden, except the marginal field of tegmina that is pale yellow ( Fig. 5A ). Head with vertex dark coffee and face pale yellow with a coffee horizontal band between antennal sockets. Ventral side of middle and hind coxae with 2–3 brown spots, while dorsal side of front coxa with 2 brown spots.

Head triangular with big reniform eyes not globose. Eyes extending postero-laterally beyond to the antennal sockets. Interocular distance slightly less in length than distance between antennal sockets. Globose and elongated face with short sparse bristles and gena bare. Antennae filiform and with short setae along their length, first flagellar segment slightly longer that the pedicel.

Pronotum parabolic with anterior margin convex and posterior margin obtuse-angulate produced with a broadly rounded apex to the middle. The two pairs of wings surpassing the cerci apexes, except in the female of X. berenbaumae . Tegmina with base of the remigium narrower than base of vanal region (vannus), with discoidal sector longitudinal and rounded apex. Hind wings with small intercalated triangle, ulnar vein vary from 3 to 6 branches in males and from 1 to 5 branches in females.

Legs long and slender.Antero-ventral margin of front femur with a row of heavy spines which decrease gradually in size meso-distal and with two terminal spines. Postero-ventral margin of front femur with 4-5 heavy spines and one terminal spine. Both margins of middle and hind femora with heavy spines of almost the same length, with genicular spine. Tarsomeres I–IV with small pulvilli. Tarsal claws simple and symmetrical, arolium present.

Abdomen often convex and long with tergal modification on abdominal segments VII. The tergal modification as a central oval deep pit or an oval shallow depression, as in X. cantralli . Also, tergal modification partially covered by a broad, rounded medial projection of posterior margin of segment V, as in X. festae (Griffini) , X. mira Gurney , X. panamae Gurney and X. potrix Gurney (see Gurney 1939 plate 14 figs 14, 20, 22, 25), or uncovered ( Fig. 5B ). Posterior margin of segment VI usually borders the anterior margin of the depression or the pit ( Fig. 5B ). Supraanal plate semi-triangular with posterior margin slightly bilobed ( Fig. 5D ). Paraprocts transverse and with spines in its margins ( Fig. 5C ). Long and thin cerci. Male subgenital plate asymmetric with each style different in shape and length. The right style located at the end of a column-like projection formed by the projection of the plate from right posterior margin ( Fig. 5E ).

Genital sclerites. Sclerite L2 thin and elongated with region L2a strongly sclerotized unlike the process “via” which is imperceptible ( Fig. 5F ). The sclerotized region of hla-hook (sclerite L3) with distal area narrow and elongated. In addition to the notch “45”, the hook also exhibits groove “hge” along of its lower margin ( Fig. 5G ). Basal area of L3 three times longer than its apical area. Membranous tube of hla-hook bare. Sclerite L4 as a strongly sclerotized dorso-lateral plate, except in X. zeteki where is absent.

Genital sclerite R formed by the sclerotized regions R1, R2 and R3 ( Figs 5H–J ). Region R1 as a large and bulky structure at the right postero-lateral region of sclerite R. Upper right corner of R1 (R1c) articulated with lower right corner of region R3 (articulation A3). Subregion R1v extends anteriorly to R 1t partially covering the R 1t +R2 complex. Subregion R 1t merged with region R2, forming the complex R 1t +R2. R2 longer than R 1t. Both elongated and pointed but only apex of R2 extending beyond posterior margin of R3. Subregion R2i articulated from its quadrangular base with left corner of posterior margin of R3. R2i with two projections, proximal projection shorter and thinner than the distal one, and the distal one generally with multiple short digitiform projections with spiniform apexes ( Fig. 5J ), except in X. zeteki . Region R3 as a slightly sclerotized triangle shaped plate. Corners of posterior margin not aligned, left corner relative to right corner displaced vertically upwards more one-third the length of the right side of R3 ( Fig. 5I ). Region R4 only present in X. zeteki as a weakly sclerotized plate.

Distribution and Biology. Xestoblatta (sensu stricto) species range from southern Mexico to southern Brazil ( Fig. 1D ). All species of Xestoblatta (sensu stricto) were observed active during the first hours of the night on the vegetation at low altitude and on the litter. These insects are strongly attracted to carrion.

Figures

FIGURE 1. Geographic sampling for genetic and morphology data. (A) Genetic sampling for Xestoblatta (sensu lato). (B) (C) (D) correspond to morphology data obtained from either specimen examination or literature records. Colors correspond to clades shown in Fig. 2.

FIGURE 5. The genus Xestoblatta (sesu stricto). A–H, Xestoblatta zeteki Gurney (male) (BLA 007). A, Habitus (dorsal); B, Abdominal segments VI and VII (dorsal); C, Lefth paraproct (ventral); D, Supra-anal plate (dorsal); E, Subgenital plate (ventral). F–J, Genital sclerites, (F) L2 (dorsal), (G) L3 (ventral), (H) R with membranes (dorsal), dashed lines indicate cuts on the membranes, (I) R without membranes and (J) Xestoblatta cantralli Fisk & Gurney, R2i (dorsal). The arrows in 5H-I indicates the regions and subregions of the sclerite R. Scale bar 1mm.