Adetus croton, Heffern & Santos-Silva & Botero, 2019

Heffern, Daniel, Santos-Silva, Antonio & Botero, Juan Pablo, 2019, A new genus and two new species of Apomecynini, a new species of Desmiphorini and new records in Lamiinae and Disteniidae (Coleoptera), Zootaxa 4691 (5), pp. 561-574 : 565-570

Adetus croton sp. nov.

( Figs. 6–13 , 17, 19 )

Description. Male ( Figs. 6–9, 13 , 17, 19 ). Integument mostly dark brown; mouthparts dark reddish brown, except yellowish-brown apex of palpomeres.

Head. Frons finely, moderately abundantly punctate; with pale yellow pubescence nearly obscuring integument (more yellowish-brown toward vertex), with short white setae interspersed. Vertex, antennal tubercles, area behind eyes, and genae finely punctate (punctures sparser than on frons); with pale yellow pubescence, more yellowishbrown between upper eye lobes, nearly obscuring integument, except on area of vertex close to prothorax, with short white setae interspersed. Genae about as long as lower eye lobe. Postclypeus with punctures distinctly finer than on frons on wide central area, smooth laterally; with pale yellow pubescence close on wide central area close to frons, white, slightly longer, bristly close to anteclypeus, with long yellowish setae interspersed. Labrum minutely, sparsely punctate close to anteclypeus, densely on remaining surface; with yellowish-white pubescence not obscuring integument close to anteclypeus, with long, erect, moderately abundant yellowish-brown setae on remaining surface, and fringe of moderately short yellowish-brown setae on anterior margin. Distance between upper eye lobes 0.82 times length of scape (0.36 times distance between outer margins of eyes); in frontal view, distance between lower eye lobes 1.48 times length of scape (0.65 times distance between outer margins of eyes). Antennae 0.85 times elytral length, reaching middle of elytra. Scape, pedicel, antennomere III, entire basal third and remaining dorsal and lateral surface of VI, and dorsal and lateral surface of V–VI with elongate, both pale yellow and white scale-shape setae obscuring integument (pale yellow setae gradually sparser and more slender toward VI); remaining surface of IV–VI and VII–XI with brownish pubescence with yellowish and whitish short setae interspersed (white setae becoming nearly absent toward IX); ventral surface of antennomeres III–VIII with long, erect brown setae, gradually shorter and sparser toward VIII; antennomeres with short, erect, sparse yellowish setae throughout. Antennal formula (ratio) based on length of antennomere III (only holotype measured): scape = 0.52; pedicel = 0.18; IV = 0.57; V = 0.34; VI = 0.28; VII = 0.27; VIII = 0.24; IX = 0.23; X = 0.21; XI = 0.24.

Thorax. Prothorax cylindrical, slightly longer than wide, slightly rounded laterally. Pronotum coarsely, abundantly punctate; with dense, thick (nearly scale-shaped) pale yellow setae laterally, with moderately abundant white setae interspersed (also nearly scale-shaped); wide central area with thick yellowish-brown setae (nearly scaleshaped), not obscuring integument, with thick white setae (nearly scale-shaped) interspersed (white setae slightly more abundant on transverse band about middle). Sides of prothorax with setae as on sides of pronotum; with one long, erect brownish seta posteriorly. Prosternum with pale yellow and white pubescence not obscuring integument; apex of prosternal process with fringe of pale yellow setae. Ventral surface of meso- and metathorax coarsely, moderately abundantly punctate; with abundant pale yellow setae, not obscuring integument, with white setae interspersed. Scutellum with yellowish-brown pubescence nearly obscuring integument, with white setae interspersed. Elytra. Almost parallel-sided in anterior 3/4, gradually narrowed toward apex in posterior quarter; apex individually rounded; anterior 3/4 mostly with thick yellowish-brown pubescence, not obscuring integument, with thick white setae interspersed, forming small tufts on sides and apex of anterior third; posterior quarter with yellowish-brown pubescence, with white setae interspersed, forming wide transverse band about basal half of this area (not reaching epipleural margin); with small white pubescent spot on dorsal side placed about middle. Legs. Femora with both yellowish-brown and white thick setae dorsally and laterally, slender and slightly longer ventrally. Protibiae gradually and moderately widened toward apex; with thick, abundant yellowish-brown setae dorsally and laterally, with white, thick setae interspersed, and dark brown pubescence ventrally. Meso- and metatibiae nearly conical, especially metatibiae, dorsally and laterally with thick yellowish-brown setae interspersed with white setae, slender yellowish-white ventrally.

Abdomen. Ventrites with pale yellow pubescence, with white setae interspersed, more abundantly on sides of ventrite V; with fringe of yellow pubescence on apex of ventrites I–IV.

Female ( Figs. 10–12 ). Differs from male especially by the meso- and metatibiae ( Fig. 12 ) distinctly slender.

Variation. White pubescence on anterior area of elytra forming moderately dense band; pubescence on posterior antennomeres yellowish; pubescence on elytra absent on some small irregular areas (not lost).

Dimensions (mm) (holotype / paratype males/ paratype females). Total length, 6.80/4.25–7.15/4.85–8.35; prothoracic length, 1.45/0.90–1.40/1.05–1.70; anterior prothoracic width, 1.25/0.75–1.30/0.95–1.55; posterior prothoracic width, 1.30/0.80–1.30/0.90–1.60; maximum prothoracic width, 1.40/0.90–1.45/1.00–1.75; humeral width, 1.70/1.05–1.75/1.20–2.15; elytral length, 4.95/3.15–5.30/3.50–6.00.

Type material. Holotype male from the UNITED STATES OF AMERICA, Texas: Hidalgo Co., Santa Ana NWR, 23.IV.2009, D. Heffern & B. Raber col. ( TAMU).

Paratype. UNITED STATES OF AMERICA, Texas: 6 males, 2 females, same data as holotype (3 males, 2 females DHCO; 1 male JVCO; 1 male WHTC; 1 male MPUJ: MPUJ _ ENT 0066028 ) ; 5 males, 2 female, same data as holotype except 27.III.2010 (2 males DHCO, 2 males, 1 female BRCO, 1 male TCMC, 1 female MPUJ: MPUJ _ ENT 0066029 ) ; 1 male, 1 female, same data as holotype except 31.V.2009 (male DHCO, female BRCO) ; 3 males, 1 female, same data as holotype except 6.VI.2010 (3 males DHCO, female BRCO) ; 1 female, Santa Ana NWR, emerged IV-2010 ex. Croton sp. 26.064450 ºN / 98.141647ºW, B. Raber & D. Heffern col. ( BRCO) ; Cameron Co., Hwy 4, Palmito Hill (on Croton humilis L.) , 1 male, 3 females, 6.V.1989, D.J. Heffern col. (male DHCO; 1 female LGBC; 2 females ACMT) ; 1 male, same data except 21.X.1989, D.J. Heffern col. ( MPUJ: MPUJ _ ENT 0066030 ) ; 3 males, 2 females, same data except 17.IV.1993, D.J. Heffern col. (1 male JVCO; 1 female DHCO; 1 female SWLC; 2 males MZSP) ; 1 male, same data except 9.V.1998, D.J. Heffern col. ( JVCO) ; 2 males, 1 female, same data except 24.IV.2010, Heffern & Raber col. (males DHCO; female WHTC) ; 3 females, 2.6 mi. E Palmito Hill , 25.96012 ºN / 97.25343 ºW, on Croton humilis L., 5.VI.2009, Heffern & Riley col. (2 females MZSP, 1 female DHCO) ; 1 female, same data except 10.X.2009, Heffern & Raber col. ( DHCO) ; 1 male, 2.4 mi. E Palmito Hill , 29–30.V.2009, Heffern & Raber col. ( SWLC) ; 2 males, 1 female, 2.4 mi. E Palmito Hill , 25.96232 ºN / 97.25797 ºW, 3.IV.2009, B. Raber & D. Heffern col. ( BRCO) ; 1 male, same data except 6.VI.2009, Heffern & Riley col. ( DHCO) ; 3 females, Lower Rio Grande Valley NWR Loma Unit, Massey Way , 25.96012 ºN / 97.25343 ºW, 9.X.2009, B.Raber & D. Heffern col. ( BRCO, TCMC, RLAC) ; 2 males, 1 female, same data except 4.IV.2009 (1 male, 1 female BRCO, 1 male RLAC); Hwy 4, 3 mi. E Palmitto Hill , 9 males, 9 females, 6.V.1989, beaten from Croton humilis, D. Heffern col. (1 male, 1 female ACMT; 1 female GDCO; 1 male, 1 female JGCO; 4 males, 2 females CMNH; 3 males, 2 females RAAC; 2 females DHPC) ; 1 male, 4 mi. E Palmitto Hill , 22.IV.1990, D. Heffern col. ( LGBC) ; 2 males, 2-4 mi. E Palmitto Hill , 26.X.1991, D. Heffern col. ( DHCO, GDCO) ; 1 male, Palmito Hill, on Hwy 4, 6.IV.1987, E. Riley & D. Rider col. ( ERCO) ; 2 males, 3 females, Hwy 4, E Brownsville, 4.V.1987, E.G. Riley col. ( ERCO) ; Cameron Co. 10 mi. W of Boca Chica Hwy 4 (sweeping Croton species) , 2 females, 5 males, 21.X.1989, R. Morris col. ( RFMC) ; 1 male, 2 females, 10 mi. W Boca Chica, Hwy 4, 21.X.1989, R. Morris col. ( ACMT) ; 1 male, 1 female, same data, ( RMBC) ; 3 males, 2 females, 11 mi. E Brownsville Rt. 4, 8.V.1999, R. Androw & S.M. Clark col. ( RAAC) ; 1 male, same data except 6.V.1999 ( RAAC) ; 1 male, 12.5 mi. E Brownsville, on Hwy 4, 14.X.1988, E.G. Riley col. ( ERCO) ; 5 males, 1 female, Ebony Loma , 12.5 mi. E Brownsville, 5.V.1989, E. Riley col. ( ERCO) ; 1 male, 1 female, same data except 21.X.1989, E.G. Riley col. ( ERCO) ; 2 males, 1 female, E Brownsville , 5.V.1989, E.G. Riley col. ( ERCO) ; 10 km E Brownsville (on Croton humilis L.) , 3 females, 14.X.1988, R. Anderson col. ( TAMU) ; 20 km E Brownsville , 1 male, 14.X.1988, R. Anderson col. ( TAMU) ; Laguna Atascosa Natl. Wdlf. Refuge (Unit 7) , 2 females, 4.V.1989, E.G. Riley col. ( TAMU) ; Loma Unit (Site 3), Palmito Hill Marker, Hwy 4, 25.96168ºN / 97.30152ºW , 1 male, 10.X.2009, Quinn & Riley col. ( TAMU) . MEXICO, Chiapas: La Libertad , 1 male, 24.VI.1985, D.J. Heffern col. ( DHCO) ; 17 km W Tuxtla Gutiérrez , 3.300 ’, 1 male, 1–8.VII.1986, J.E. Wappes col. ( ACMT) . Jalisco: JAL 428, 4km E of La Croix (beating slash) , 1 male, 8.VII.2006, Skillman & Hildebrand col. ( FWSC) . Michoacán: Hwy 15, 21 mi. E Morelia, 7000 ’, 1 male, 15.VIII.1982, C.W. & L. O’Brien & G. Wibmer col. ( ACMT) .

Nuevo León: 17 mi. W Linares , 1 male, 11.V.1994, J.E. Wappes col. ( ACMT) . Quintana Roo: 18–24 km N Felipe Carrillo Puerto , 1 male, 1 female, 27.V–1.VI.1984, J.E. Wappes col. ( ACMT) ; 20 km N Felipe Carrillo Puerto , 2 males, 12–14.VI.1983, J.E. Wappes col. ( ACMT) ; Hwy 180 4–15 km W MX 307 (beating old slash), 2 males, 3.VI.2009, F. W. Skillman, Jr. col. ( FWSC) ; Hwy 186, 17 km W of 307, 1 male, 30–31.V.1984, J.E. Wappes col. ( ACMT) . Sonora: SON 12, Cuba nr. Nuri (beating), 2 females, 3.VII.2008, Skillman, O’Brien, Ribardo col. ( FWSC) . Tamaulipas: Bocotoma area , 7 km SSE Gomez Farias , 1 male, 1–4.VI.1982, J.E. Wappes col. ( ACMT) ; 1-2 mi. E N. Morelos , 1 female, 2.VI.1982, J.E. Wappes col. ( ACMT) ; Road to Ocampo , 9.3 mi. W Hwy 101, 2 males, 31.V.1982, J.E. Wappes col. ( ACMT) . Yucatán : 1–2 km E Chichén Itzá , 1 male, 2 females, 25–27.V.1984, J.E. Wappes col. ( ACMT) ; 4km SW Espita (bulldozed veg), 1 male, 24.X.1991, F. W. Skillman Jr. col ( FWSC) . HONDURAS, Francisco Morazán: 13 km S El Tigre , 1 male, 2 females, 19.V.1995, J.E. Wappes col. ( ACMT) .

Remarks. Adetus croton sp. nov. is similar to A. bacillarius Bates, 1885 ( Figs. 14, 16, 18, 20, 24 ), and has been confused with it. However, the new species differs from it as follows: meso- ( Fig. 17 ) and metatibiae ( Fig. 19 ) of males proportionally shorter and conical, especially metatibiae; mesotibiae not excavated dorsally on posterior third, and without fringe of thick and erect setae ( Fig. 17 ); pronotum not longitudinally sulcate on each side of central area ( Figs. 6, 10, 13 ); elytra with two wide transverse white pubescent bands (sometimes, the anterior one ill-formed) ( Figs. 6, 10, 13 ); lower eye lobes ( Fig. 9 ) smaller. In A. bacillarius , the meso- ( Fig. 18 ) and metatibiae ( Fig. 20 ) of males proportionally longer and not conical, mesotibiae ( Fig. 18 ) of males excavated dorsally on posterior third, and with fringe of thick and erect setae ( Fig. 18 ), pronotum longitudinally sulcate on each side of central area (sometimes slightly distinct, especially depending on the angle of view) ( Figs. 14, 24 ), elytra without transverse white pubescent bands ( Figs. 14, 24 ), and lower eye lobes ( Fig. 16 ) larger. The new species is also similar to A. modestus Melzer, 1934 ( Figs. 15, 21 ), but differs by the prothorax slightly slender and elongate ( Figs. 6, 10, 13 ), metatibiae in male proportionally shorter and conical ( Fig. 19 ), and antennomeres from IV proportionally shorter and stouter ( Figs. 6, 10, 13 ). In A. modestus , the prothorax is slightly stouter and shorter ( Fig. 15 ), metatibiae in male are proportionally longer and not conical ( Fig. 21 ), and antennomeres from IV proportionally slender and longer ( Fig. 15 ). The new species also can be separated from A. brousii (Horn, 1880) ( Fig. 22 ), and A. binotatus (Thomson, 1868) ( Fig. 23 ), especially by the shape of the metatibiae ( Fig. 19 ).

Adetus croton sp. nov. also differs from A. tibialis Breuning, 1943 ( Fig. 25 ), A. proximus Breuning, 1940 ( Fig. 26 ), and A. irregularis (Breuning, 1939) ( Fig. 27 ), by the same features of A. bacillarius . We believe that those species are junior synonymies of A. bacillarius . However, we prefer not to establish the synonymies without detailed studies, which are beyond the scope of this work.

Host plant. This new species was initially discovered in Texas by Edward Riley in 1987 while collecting Chrysomelidae on the shrub, Croton humilis L. ( Euphorbiaceae ), along Highway 4 near the Palmito Hill historical marker in Cameron County. Eventually, one specimen was reared from a stem of this plant by Brian Raber. All of the specimens collected in Southern Texas, we believe, were collected by beating or sweeping C. humilis , even though many labels do not indicate this. The known localities in Texas where this new species has been collected are all located in either the Lower Rio Grande Valley National Wildlife Preserve (LRGVNWR), Laguna Atascosa National Wildlife Refuge (LANWR) or Santa Ana National Wildflife Preserve (SANWR). At SANWR, a small area of about 200 square meters with Croton humilis shrubs was located near the east entrance of the old, historic cemetery within the refuge. The plants were checked multiple times before individuals were found on one visit to the refuge. In the summer of 2010, this area was inundated by unprecedented flood waters for several months. The subsequent status of this population has not been determined. The localities in LRGVNWR and LANWR were unaffected by that flood. There are undoubtedly other locations for this species, however the remaining undeveloped land in Southern Texas is largely private property or protected federal property where permission to collect is required.

Etymology. This species is named for its host plant in Southern Texas: Croton humilis L.

Figures

FIGURES 6–13. Adetus croton. 6–9) Holotype male: 6) Dorsal habitus; 7) Ventral habitus; 8) Lateral habitus; 9) Head, frontal view. 10–12) Paratype female: 10) Dorsal habitus; 11) Ventral habitus; 12) Metatibiae. 13) Paratype male, dorsal habitus.

FIGURES 14–27. 14) Adetus bacillarius, male from Bolivia (Santa Cruz), dorsal habitus. 15) A. modestus, holotype female, dorsal habitus. 16) A. bacillarius, male from Brazil (Roraima), head, frontal view. 17) A. croton, holotype male, mesotibia. 18) A. bacillarius, male from Bolivia (Santa Cruz), mesotibia. 19–23) Metatibia, male: 19) A. croton, paratype; 20) A. bacillarius; 21) A. modestus; 22) A. brousii; 23) A. binotatus. 24–27) Dorsal habitus: 24) A. bacillarius, lectotype male; 25) A. tibialis, holotype male; 26) A. proximus, holotype male; 27) A. irregularis, holotype.