Xanthonia marquai Riley & Quinn, 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 : 6-8

2. Xanthonia marquai Riley & Quinn n. sp.

( Figs 11 , 14, 22, 30–31; Map 2 )

Holotype. Here designated, ♂ (Fig 14) with the following labels: || TEXAS: Jeff Davis Co. | Davis Mts. Resort, 5,800 ft. | (Marqua residence) | 30.62842°N, 104.08360°W | VI-26–27-2010, E. G. Riley || beating | Juniperus | sp. || [red label] HOLOTYPE | Xanthonia | marquai | Riley & Quinn ||. Deposited in TAMU. The specimen is pointmounted and dissected, with abdomen and genitalia affixed to the point. It is in excellent condition with all appendages intact .

Paratypes (37 total) TEXAS: Jeff Davis Co., Davis Mts. Resort (Marqua residence), 5,800 ft., VI-26-1994, E. G. Riley [1 EGRC] ; same data, except 30°37’42”N, 104°05’01”W, VI-22–23-2002 [6 EGRC] ; same data as holotype [23 total: AJGC, BYUC, EGRC, TAMU, USNM]; Madera Canyon rest stop, 30.70613°N, 104.10484°W, VII-4-2009, E. G. Riley, beating Juniperus deppeana Steud. [1 EGRC]; Davis Mts. Resort, 5800’, VII-5-12-1993, D. Marqua, malaise trap [1 TAMU], same locality, VII-16-1994, D. G. Marqua [1 TAMU]; same data, except VII- 3-1996 [1 TAMU]; same data, except IX-15-2003 [1 TAMU]; Madera Canyon, rest stop, Hwy. 118, VIII-7-1992, W. Godwin & E. Riley [2 TAMU] .

Diagnosis. Size large, length 3.9–4.9 mm; ground color of dorsum uniformly medium brownish, elytral hairs uniformly light yellow-brown, ( Fig 11 ), venter medium brown; ventral tooth of profemur large ( Fig 22 ); lateral margins of all ventrites entire; median lobe of male genitalia long and narrow, evenly tapered to non-incised apex ( Fig 30 ).

Description. Color: Head dark reddish brown, labrum and basal segments of antennae yellow brown, distal segments obscurely darker. Pronotum and elytra uniform medium brown ( Fig 11 ). Venter medium brown as dorsum. Legs dark reddish brown, femora slightly darker. Form: Length 4.9–6.1 mm Head densely and coarsely punctate throughout with pale closely appressed pubescence, face with median line not evident to faint on vertex, inter-antennal area flat. Pronotum densely and very coarsely punctate with long pale brown closely appressed pubescence; pronotal width averaging 1.48 times its length, widest behind middle; sides moderately rounded in dorsal aspect; anterior transverse depression and lateral impressions shallow. Elytra with length averaging 1.42 times their combined width, 2.73 times length of pronotum; basal callosity evident; punctures in regular rows on disc including post-scutellar area and behind callosity, confused below humerus; punctures moderate in size, nearly as large as intervals on disc; intervals flat on disc, becoming slightly elevated near lateral margins and apex; pubescence composed of strongly reclined to recumbent hairs in double rows on intervals and very short obscure hairs contained within punctures. Metasternum completely smooth and lacking coarse punctures, very finely rugose in anterolateral angles. Abdomen with ridge on lateral margins of all ventrites entire, last segment of male flat without tubercles. Ventral tooth of profemur large and broad ( Fig 22 ), distinct small ventral tooth on meso- and metafemora. Median lobe of male genitalia in en-face view long and narrow, evenly tapered to pointed apex without incision ( Fig 30 ).

Range. Thus far, this species is known only from the Davis Mountains of western Texas ( Map 2 ).

Plant associations. As with X. vagans , this species is likely a juniper specialist. Most of the type specimens were beaten from a single unidentified juniper tree having the general habitus of Juniperus ashei J. Buchholz. One specimen was beaten from Juniperus deppeana Steud ..

Seasonal Distribution. Taken during June, July and September.

Remarks. Very close to X. vagans with which it shares most characters except the coloration. In X. marquai , both the medium reddish brown integument and the pale brownish pubescence are consistent in color throughout, giving these beetles an immaculate uniform appearance, whereas in X. vagans the mixed light and dark elytral hairs and, in most specimens, the light and dark brownish-streaked coloration of the elytral integument combine to impart a maculate appearance. On average, the body of X. marquai seems a trifle broader relative to its length than that of X. vagans .

This species is named to honor of David G. Marqua (1924–2017), beetle collector and Davis Mountains’ resident. Dave’s former residence at 5,800 ft. in the Davis Mountains is likely the best entomologically-known locale in the Davis Mountains, due to his personal collecting efforts, his warm friendly nature, and his long-standing invitation to countless insect collectors.

Specimens examined. See type data above. The genitalia of five males from one locality were examined.

Figures

FIGURES 10–12. Xanthonia species, dorsal habitus. 10) X. vagans (Cochise Co., Arizona); 11) X. marquai (Jeff Davis Co., Texas); 12) X. hirsuta (Travis Co., Texas). Scale bars = 1 mm. Figs 13–16. Xanthonia species, types and type labels. 13) X. vagans (courtesy of the MCZ type database); 14) X. marquai; 15) X. picturata; 16) X. villosula.

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.