Trichodesma nancyae Schnepp, 2023

Schnepp, Kyle E., 2023, An illustrated type catalog of Trichodesma LeConte, 1861 (Coleoptera: Ptinidae) from Mexico, with description of a new species, Insecta Mundi 2023 (24), pp. 1-19 : 2-3

Trichodesma nancyae Schnepp , new species

Figures 1–2 , 23–28

Type material. Holotype, male ( FSCA): “ MEXICO: Guerrero / 10 km. N Chilpancingo / 22 July 1987 / R. Turnbow // [on red] HOLOTYPE / Trichodesma nancyae / Schnepp, 2023 ”.

Paratype, undissected ( FSCA): “ MEXICO, GUERRERO: / HWY. 95, 3.6 Km S. / Zumpango del Rio // G. H. Nelson / 7-VII-92 // on Acacia / cochliacantha // [on yellow] PARATYPE / Trichodesma / nancyae / Schnepp, 2023 ”.

Diagnosis. Trichodesma nancyae is distinguished from all other named species of Trichodesma by the large, dark, brown circle on the middle of the elytra, as well by the lack of long, erect setae on the elytra. The only similar species in Mexico with a round marking on the elytra are Trichodesma beyeri Fall and Trichodesma discigera Champion , both of which differ from T. nancyae by the circle being created by a reduction of setae, not the presence of dense, short brown setae. They also differ in having distinct, long erect setae.

Description. Holotype: Sex: male. Length: 6.1 mm; width: 3 mm. Overall body form elongate oval. Head: Frons covered with short, pale pubescence that becomes shorter and less dense posteriorly. Eyes large, interocular distance slightly wider than each eye in anterior view. Antennae with 11 antennomeres, the last three forming a club; antennomeres IX and X equal in length, antennomere XI as long as antennomeres II–VIII combined; antennomere IX securiform, widening on one side from base to apex; antennomere X widening on one side from base to apex but not as wide at apex as antennomere IX; antennomere XI similar width throughout, becoming slightly wider apically. Pronotum: Gibbous, covered in shiny, generally distributed round asperities; widest in anterior third, converging slightly anteriorly with anterior angles produced, converging very broadly posteriorly with a sinuation in the basal third. Laterally with a strong carina from base to apex. Generally covered in pale appressed setae with a sparsely covered patch each side posterolaterally and at the anterolateral angles. On the disc, at the apex of the gibbosity, are four patches of brown setae, the anterior pair larger than the posterior pair, each separated by a thin line of white pubescence. Elytra: Basally with irregularly distributed shiny, round asperities. Generally covered in a dense, pale, appressed pubescence, with a denuded sparse patch on each elytron mediobasally, apically, and the apical 1/4 from the suture anterolaterally. The general pale pubescence developing a brown tinge laterally. Dark, erect setae are present irregularly; punctures are deep and distinct, and clearly separated. There is a common brown circle medially on the disc made of a dense patch of short setae, basally this circle with a slight divot of white pubescence either side of the suture, and the apex with a slight intrusion of white pubescence along the suture; the lateral portion of the divot with erect brown setae. Lateral to the central spot is a smaller brown spot on the lateral 1/4 of each elytron. In the denuded patch at the apical 1/4 are three small brown patches of erect setae. Legs: Covered in pale, generally appressed pubescence, tibiae with outer margin with denser pubescence and long, erect setae. Femur and tibia equal in length; tarsi with basal and apical tarsomeres equal in length, middle three tarsomeres slightly shorter and equal in length to one another; each tarsomere with dense pale setae beneath; tarsal claws with basal tooth. Venter: Ventral portions of the thorax with distinctly separated shiny, round asperities, between which is appressed, moderately dense pale pubescence. Abdomen generally covered with appressed, moderately dense, pale pubescence with tracks or small patches of denuded areas where instead there are shiny asperities. Genitalia ( Fig. 28 ): Viewed dorsally, parameres elongate with a lateral extension that first curves arcuately away from the genitalia and then back toward the median lobe where it ends as it begins to recurve laterally again; this lateral extension is slightly longer than the median lobe. The portion of the parameres beyond this extension is more heavily sclerotized and bifid at the apex. The median lobe expanding from the base, widest in the middle, and converging to an acuminate apex. Medially there is a slightly impressed channel basally that expands apically until it opens up and merges with the opposite surface at about the middle of the lobe.

Variation (n = 2). The paratype is slightly larger than the holotype at 6.3 mm long and 3.1 mm wide but is similar in virtually all characters. It is not dissected but matches the holotype in antennal size and length, and eye size, often dimorphic characters in this genus.

Distribution. Both specimens were collected between Chilpancingo and Zumpango in the state of Guerrero, Mexico.

Etymology. Named for Nancy Schnepp, whose endless support allowed the author to professionally do what he loved and research insects; not all mothers are thrilled with a freezer full of bugs, but she was never fazed.

Temporal data. Two specimens, both collected in July.

Figures

Figures 1–2. Trichodesma nancyae Schnepp, new species, paratype. 1) Dorsal habitus. 2) Lateral habitus.

Figures 23–26. Trichodesma nancyae Schnepp, new species, holotype. 23) Dorsal habitus. 24) Lateral habitus. 25) Frontal habitus. 26) Specimen labels.

Figures 27–28. Trichodesma nancyae Schnepp, new species, holotype. 27) Ventral habitus. 28) Male genitalia.