Xanthonia picturata Weisman & Riley, 2019

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

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

( Figs 6 , 15, 23, 32–33, 61; Map 4 )

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] . 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]

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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 , 15), venter dark brown to black; ventral tooth of profemur moderately large ( Fig 23 ); 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 ).

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 , 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 ), 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 ).

Range: Much of central and eastern Texas to extreme south-central Oklahoma ( Map 4 ).

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 ).

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.

Figures

FIGURES 1–9. Xanthonia species, dorsal habitus. 1) X. angulata (Bastrop Co., Texas); 2) X. dentata (Jeff Davis Co., Texas); 3) X. furcata (Wood Co., Texas); 4) X. nitida (Pecos Co., Texas); 5) X. parva (Kerr Co., Texas); 6) X. picturata (Robertson Co., Texas); 7) X. querci (Val Verde Co., Texas); 8) X. texana (Bandera Co., Texas); 9) X. villosula (Bossier Parish, Louisiana). Images to scale, scale bar = 1 mm.

MAPS 1–6. Distribution of Xanthonia species. 1) X. vagans; 2) X. furcata (■), X. marquai (♦), X. nitida (●); 3) X. hirsuta; 4) X. picturata; 5) X. angulata (♦), X. dentata (●), X. querci (■); 6) X. parva (■), X. villosula (●).

FIGURES 17–26. Xanthonia species, margins of ventrites III–V. 17) X. dentata; 18) X. parva; 19) X. villosula; 20) X. angulata. Figs. 21–22. Xanthonia species, profemora. 21) X. vagans; 22) X. marquai; 23) X. picturata; 24) X. hirsuta; 25) X. texana; 26) X. parva.

FIGURES 27–54. Xanthonia species, en-face and lateral view of median lobe. 27) X. vagans (Palmerlee, Arizona); 28–29) X. vagans (Chisos Mts., Texas); 30–31) X. marquai (Jeff Davis Co., Texas); 32–33) X. picturata (Gonzales, Texas); 34–35) X. parva (Kerr Co., Texas); 36) X. villosula (Miller, Indiana); 37) X. villosula (Dallas, Texas); 38–39) X. villosula (Natchez, Mississippi); 40) X. dentata (Socorro Co., New Mexico); 41) X. dentata (Sapello, New Mexico); 42) X. dentata (Chisos Mts., Texas); 43–44) X. dentata (Cloudcroft, New Mexico); 45–46) X. hirsuta (Dallas, Texas); 47–49) X. texana (Victoria, Texas); 50) X. nitida (San Antonio, Texas); 51–52) X. nitida (Dallas, Texas); 53–54) X. querci (Dallas, Texas). All figures from Weisman (1960), except 30–31 and 32–33.

FIGURES 61–63. Seasonal distribution of Xanthonia species from Travis County, Texas (data from Quinn, 2000). 61) X. picturata; 62) X. hirsuta; 63) X. texana. Table 1. Quantitative plant association data for Xanthonia species from Travis County, Texas (data from Quinn, 2000)