Brasixenos mesoamericanus Quintos-Andrade & Valenzuela-González, 2023

Quintos-Andrade, Gerardo, Valenzuela-González, Jorge Ernesto, Palmeros-Sánchez, Beatriz & Torres-Moreno, Raymundo, 2023, A new species of Brasixenos Kogan & Oliveira, 1966 (Strepsiptera: Xenidae) from Mexico, Zootaxa 5343 (4), pp. 386-394 : 388

Brasixenos mesoamericanus Quintos-Andrade & Valenzuela-González sp. nov.

Female cephalothorax

( Fig. 2 )

Diagnosis. Light brown coloring with a more intense shade on the head and sclerotized areas. Mandibles angled at 60°; inconspicuous mandibular bulge; tooth inserted into the internal margin, sharp, oppositely oriented to the mouth position and towards the front, covered with protuberances. This is the Brasixenos species with the smallest cephalothorax (average length-width: 0.86 mm / 0.89 mm). Morphologically it is similar to B. bahiensis Kogan & Oliveira and B. brasiliensis Kogan & Oliveira , but they differ by their larger size (Length-width of B. bahiensis : 1.16 mm / 1.30 mm. Length-width of B. brasiliensis : 1.40 mm / 1.50 mm), as well as presenting the mandibular tooth away from the internal margin. The mandibular teeth are straight in B. bahiensis , whereas in B. brasiliensis the teeth are oriented towards the side margin.

Description. Shape and coloration. Length. 0.86 mm; width. 0.89–0.93 mm. Cephalothorax rounded, wider than long. Rounded head, slightly pronounced frontal region. Mesothorax wider than the head, without constriction. Light brown color, darker on the sclerotized areas of the head, thorax margins and spiracles; light color mandibles. Head capsule. Head length: 0.13–0.15 mm. Head width: 0.47–0.53 mm. Light brown color without a specific pattern. Smooth frontal cuticle without sensilla. Clypeus and labrum fused but recognizable. Clypeal cuticle smooth. Boundary between head and prothorax not recognizable. Supra-antennal sensillary field. Inconspicuous but recognizable, covered by scattered sensilla. Antenna. Present in the shape of a faint depression. Labrum. Fused with the clypeus, slightly projected. Arched dorsally. Covered by sensilla-inserted central cavities. Mandible. Arranged in a 60° angle and immersed in the mandibular capsule. Inconspicuous and smooth mandibular bulge, with some inconspicuous protuberances and covered by scattered sensilla. Tooth inserted into the internal margin, sharp, oppositely oriented to the mouth position and towards the front, covered in scattered spines and with the inner margin serrated. Maxilla. Fused with the labial area. Delimited by microsculpture, fine and slightly wrinkled. Maxillary apex reaching the level of the mandibular tooth. Vestigial palpi not visible. Maxillary plate absent. Labium. Fused with the maxillae. Smooth cuticle, differentiable from the maxillae. Mouth opening. Arched, almost semicircular and with sclerotized margins. Thorax. Prothorax and mesothorax delimited by shifts in coloring and sculpture, straight prosternal extension, slightly arched with scattered papillae in the anterior margin. Metathorax as clear as the mesothorax. Dorsal cuticle clearer than the ventral, smooth and with horizontal lines of papillae. First segment and spiracles. Coloring clear like the metathorax, more intense at the margins and spiracles. Spiracles located at the anterior margin, dorsally oriented, and surrounded by sensilla.

Figures

FIGURE 2. Brasixenos mesoamericanus sp. nov. A) Female cephalothorax in ventral view. B) Female cephalothorax in dorsal view. C) Male cephalotheca in dorsal view. D) Male holotype head in ventral view.