Xanthonia texana Weisman, 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 : 16-18

10. Xanthonia texana Weisman , n. sp.

( Figs 8 , 25 , 47–49 , 63 , 76 ; Map 7)

Holotype. Here designated, ♂ ( Fig 76 ) with the following labels and attachment: || Victoria | 3-30-10 TX || WD- Pierce | Collector || JDMitchell | collector || sweeping | herbage || 204 || NM || [glycerine-filled microvial containing male genitalia] || [red label] HOLOTYPE | Xanthonia | texana | Weisman ||. This specimen is dissected with the abdomen glued on the point and the median lobe contained in a glycerine-filled microvial, all appendages intact. The male genitalia are over-cleared. Deposited in USNM.

Paratypes. (43 total) TEXAS: “ Texas ” no further data [4 USNM]; Bexar Co. San Antonio, IV-8-1945, C. O. Orchard [2 USNM]; Burnet Co., Hubbard and Schwarz [1 USNM]; Blanco Co. , Cypress Mills [2 USNM] ; same locality, III-15, Chittenden Collection [2 USNM]; Kerr Co., Kerrville , IV-12-1907, F. C. Pratt [1 USNM] ; same locality, VI-19-1907, F. C. Pratt [1 USNM] ; same locality, IV-22-1908, F. C. Pratt [2 USNM]; McLennan Co., Waco, III-22-1907, W. D. Pierce, on woodbine [1 USNM]; Victoria Co ., same data as holotype [7 USNM]; Victoria , IV- 24, H. S. Barber [1 USNM] ; same locality, IV-3, E. A. Schwarz [2 USNM] ; same locality, IV-2, J. D. Mitchell [2 USNM] ; same locality, IV-2, J. D. Mitchell, on red haw [1 USNM] ; same locality, IV-13, J. D. Mitchell [2 USNM] ; same locality, III-30-1909, J. D. Mitchell, collected on pecan [4 USNM] ; same locality, IV-23-1907, J. D. Mitchell [1 USNM] ; same locality, V-29-1908, J. D. Mitchell, on Xanthium sp. [1 USNM] same locality, IV-17-1911, J. D. Mitchell, on Cornus sericea [1 USNM] same locality, IV-2-1908, J. D. Mitchell, on red haw tree [2 USNM] ; same locality, IV-18-1911, J. D. Mitchell, on flowers [2 USNM]; Wharton Co. Wharton, IV-18-1905, W. W. Yothers [1 USNM] .

Diagnosis. Size small to moderate, length 2.5–3.4 mm; ground color of dorsum light reddish brown, elytra ranging from immaculate to a pattern of well-defined brownish to black maculae ( Figs 8 , 76 ), venter of body brownish to distinctly darkened or partially black; pubescence of elytra composed of erect hairs on intervals in single lines and smaller appressed hairs arising from punctures nearly as long as erect hairs; ventral tooth of profemur minute to obsolete; lateral margins of all ventrites entire; median lobe of male genitalia broad to apex, apical emargination deep and rounded with broad lobe on each side ( Fig 47–48 ).

Description. Color: Head reddish brown, labrum and antennae yellowish brown. Pronotum reddish brown with darker area in middle of disc. Elytra light reddish brown with dark common median spot, each with dark spot at middle of base, one on humerus, a row of two or three across disc and of two or three across apical third, the discal and subapical spots tending to unite transversely and longitudinally ( Figs 8 , 76 ). Some specimens immaculate yellowish brown with light reddish brown head and prothorax, most with markings faint or reduced in number or extent. Venter reddish brown, becoming blackish on metathorax and base of abdomen. Legs yellowish brown. Form: Length 2.5–3.4 mm Head densely and coarsely punctate throughout with fine short yellow recumbent pubescence, face with median line not evident, interantennal area moderately concave. Pronotum densely and coarsely punctate, with fine recumbent pubescence, width averaging 1.35 times its length, widest behind middle; sides fairly evenly broadly rounded in dorsal aspect; anterior transverse depression moderately deep to shallow and lateral impressions obscure to absent. Elytra with length averaging 1.50 times their combined width, 2.65 times length of pronotum; basal callosity evident; punctures in fairly regular rows, confused near scutellum, behind callosity and below humeri; punctures coarse, dense, and larger than intervals on disc; intervals somewhat convex on disc, becoming weakly costate on lateral areas and at apex; pubescence composed of erect hairs in single lines on intervals and appressed hairs arising from punctures nearly as long as erect hairs. Metasternum with moderately coarse dense punctures on lateral areas. Abdomen with ridge on lateral margins of all ventrites entire, last ventrite of male flat without tubercles. Ventral tooth on profemur very small to obsolete, meso- and metafemora with tooth obsolete to absent. Median lobe of male genitalia in en-face view broad to apex, apical emargination deep and rounded with broad apically rounded lobe on each side ( Figs 47–49 ).

Range. Confined to Texas, primarily the post oak savanna and blackland prairie regions of east-central Texas, but extending well into the eastern portion of the Edwards Plateau (Map 7).

Plant associations. Weisman (1960) cited the following plant associations from label data: “on Red Haw”, “on Red Haw Tree”, “on flowers”, “on Xanthium sp.”, “collected on pecan”, “on Cornus sericea ”, and “on Woodbine”. Specimens examined during the present study were recorded on many different woody plants (see Appendix 8) but most are from Ulmus crassifolia Nutt. Data from the Travis County study, where this species was especially abundant, showed that it has a strong preference for Ulmus crassifolia with 71% of specimens collected from this tree species, followed by Quercus fusiformis Small with 19% of specimens (Table 1).

Seasonal distribution. The Texas collection dates range from March to August. In the Travis County study, the peak abundance was during early April ( Fig 63 ).

Remarks. Although differing slightly in habitus from the other species of similar size with entire ventrite margins, this species can be difficult to identify without reference to the male genitalia. Its pattern of dark maculation, when well developed, differs slightly from similar species. The short male genitalia with a deep u-shaped apical emargination are highly diagnostic. As noted by Weisman (1960), this form of male genitalia is similar to that of X. decemnotata (Say) . The alignment of elytral disc punctures is variable with most individuals displaying fairly regular rows.

Specimens examined. See Appendix 8. The genitalia of 71 males from 31 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.

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)

FIGURES 76–78. Xanthonia species, types and type labels. 76) X. texana; 77) X. querci; 78) X. furcata. Map 7. Distribution of Xanthonia texana.