Xanthonia picturata Weisman & Riley

Riley, Edward G., Weisman, Donald M. & Quinn, Michael A., 2019, A taxonomic review of the Xanthonia species occurring in Texas (Coleoptera: Chrysomelidae, Eumolpinae), Zootaxa 4668 (1), pp. 1-29: 8-9

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Xanthonia picturata Weisman & Riley

n. sp.

3. Xanthonia picturata Weisman & Riley   , n. sp.

( Figs 6 View FIGURES 1–9 , 15, 23, 32–33, 61; Map 4 View MAPS 1–6 )

Holotype. Here designated, ♀ (Fig 15) with the following labels: || Kerrville | 30.V.06 TX || FCPratt | Collector || ♀ || NM || [red label] HOLOTYPE | Xanthonia   | picturata | Weisman & Riley ||. Deposited in USNM. The abdomen is removed from the body and glued on the point. The specimen is in excellent condition with all appendages intact   .

Paratypes. (35 total): TEXAS: Brazos Co. College Station, Riley Estate , 30.58840°N, 96.25366°W, V-1–7- 2014, E. G. Riley, UV [3 EGRC]; same data, except V-1–10-2014 [17 total, AJGC, BYUC, EGRC, TAMU, USNM] GoogleMaps   . Kimbal Co. Junction, overlook area, 30°28’28N, 99°45’20”W, IV-10-2002, E. G. Riley [11 TAMU]. Uvalde Co. Sabinal, IV-1910, Pierce and Pratt [1 USNM]. Lee Co. Fedor, [1 USNM] GoogleMaps  


Diagnosis. Size moderate, length 2.6–3.6 mm; dorsal ground color dark brownish, elytra with distinct and fairly consistent pattern of black maculae ( Figs 6 View FIGURES 1–9 , 15), venter dark brown to black; ventral tooth of profemur moderately large ( Fig 23 View FIGURES 17–26 ); lateral margins of all ventrites entire; median lobe of male genitalia long and narrow gradually tapered distally, apex narrowly rounded with short narrow incision ( Fig 32 View FIGURES 27–54 ).

Description. Color: Head dark reddish brown, labrum and antennae yellowish brown. Pronotum completely dark reddish brown to nearly black sometimes with indistinct darker spot on each side of middle at base and another at middle of apical margin. Elytra dark reddish brown, each with darker spot at middle of base, one on humerus, a linear dorsal spot at suture extending along middle third, a row of three elongate spots across disc at basal third, one between outer two and humerus, a row of three across apical third and one at apex, some variation in expression and degree of fusion of these dark spots evident ( Figs 6 View FIGURES 1–9 , 15). Venter dark reddish brown to black with apex of abdomen lighter. Legs dark reddish brown. Form: Length: 2.5 to 3.6 mm Head densely and coarsely punctate throughout and with silky golden closely appressed pubescence, face with median line conspicuously impressed and extending to vertex, interantennal area nearly flat. Pronotum densely and coarsely punctate with dense silky golden appressed pubescence, width averaging 1.46 times length, widest behind middle; sides very broadly rounded in dorsal aspect; anterior transverse depression and lateral impressions shallow. Elytra length averaging 1.36 times combined width, 2.7 times length of pronotum; basal callosity slightly prominent; punctures confused over most of disc and base, at most with vague rows present, tending to form rows at suture and along lateral margins and apex; punctures coarse, dense, larger than spaces between punctures; intervals at lateral margins slightly elevated; pubescence composed of erect hairs scattered on intervals to partially aligned in rows and appressed hairs arising from punctures as long as the erect hairs. Metasternum smooth medially, finely densely punctate laterally. Abdomen with ridge on lateral margins of all ventrites entire, last ventrite of male flat without tubercles. Ventral tooth on profemur moderately large ( Fig 23 View FIGURES 17–26 ), tooth on meso- and metafemora small to minute. Median lobe of male genitalia in en-face view long and narrow gradually tapered distally, apex narrowly rounded with short narrow incision ( Fig 32 View FIGURES 27–54 ).

Range: Much of central and eastern Texas to extreme south-central Oklahoma ( Map 4 View MAPS 1–6 ).

Plant Associations. This species has been associated with several different woody plants, but it has a preference for oak species. Of the 112 specimens taken during the Travis County study, 68% were taken from Q. fusiformis Small   and 25% were taken from Quercus buckleyi Nixon & Dorr   (Table 1). Other recorded oak associations include, Q. havardii Rydb.   , Q. macrocarpa Michx.   , and Q. marilandica Münchh. Several   specimens were collected at lights.

Seasonal distribution. Collected from early March to early June. Peak abundance during the Travis County study was late April ( Fig 61 View FIGURES 61–63 ).

Remarks: This is a distinctive species, owing to its dark coloration, moderate-sized profemoral tooth, and the distinctive male median lobe. Weisman’s originally treatment of this species was based on only three females, but further field study has shown this to be one of the most abundant species in Texas (see specimens examined, Appendix 3). Specimens from the Edwards Plateau tend to be slightly smaller in overall stature than those found in the more eastern portions of the range.

Specimens examined. See Appendix 2. The genitalia of 22 males from 14 localities were examined.


Smithsonian Institution, National Museum of Natural History