Colyphus martinezi Rifkind, 2020

Colyphus martinezi Rifkind , new species

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( Figs. 18–25 View Figs )

Specimens Examined. Holotype male: Mexico, Oaxaca, 8.5 km N Diaz Ordaz , 7435 ′, 8-07-2018, J. Rifkind, E. Martinez. ( CSCA) . Paratypes: 1 M ( JNRC), 1 F ( CSCA), same data as holotype ; 1 M ( CSCA) same data as holotype, except 4.6– 9 km N Diaz Ordaz ; MEXICO, OAXACA: 1 M ( CNIN), 8.8 km NNW Diaz Ordaz (Rd to Villa Alta) , N17°02.027 ′ W96°28.331 ′, 2295 m, 19.vii.2003, C. L. Bellamy, CLB848, misc. beating GoogleMaps ; 1 F ( CNIN), Hwy. 175, 6 km S El Estudiante , 5997 ′, vi-24-2013, J. Rifkind, coll., beating roadside vegetation ; 2 M ( JNRC), 1 M, 1 F ( CSCA), 1 M ( LACM), 1 F ( CNIN), Sierra de Zempoaltepetl, 11.1 km NW Diaz Ordaz , 7400 ′, July 4, 1989, J. Rifkind, E. Barchet, A. Evans, colls., oak forest ; 1 F ( JNRC), 1 F ( CNIN), Sierra de Ixtlan, Hwy. 175, 6.7 km N El Punto , 2100 m, June 29, 1989, on thorn, E. Barchet, A. Evans, J. Rifkind ; 1 F ( WFBM), Arroyo Guacamaya, 6–10 km N Villa de Etla , oak / pine / madro~ no, vi-28-[20]13, beating, J. Rifkind, coll. ; 1 F ( JNRC), Hwy. 175, 22 mi. NE Oaxaca , 7900 ′, 30 May, 1983, C. & L. O’ Brien & G. B. Marshall.

Description ( Holotype). Length: 7 mm. Color: Black; mouthparts testaceous; anterior margin of pronotum narrowly reddish; coxae and tibiae reddish brown; each elytron with a small, rounded, dark testaceous basal macula. Head: Measured across eyes as broad as pronotum at its maximum width; surface moderately densely, but rather finely and shallowly punctate; pubescence moderately dense but not conspicuous, composed of reclinate silvery setae interspersed with somewhat longer, erect, dark setae; antenna elongate (attaining posterior margin of pronotum when laid alongside); club distinct, composed of terminal 3 antennomeres. Pronotum: Narrower than elytra at base, as long as broad; sides shallowly incised by transverse impression, then moderately convex; transverse impression moderately deep, broadly U-shaped at middle; disc flattened above; lateral foveae distinct; basal collar narrow; surface shining, densely but shallowly rugulose-punctate; vestiture moderately dense, but not obscuring integument, composed of suberect, rather robust, white setae, interspersed with longer, erect, robust black setae. Elytra: Elongate (together approximately 2× as long as wide), sides subparallel, very broadly, arcuately convergent from posterior 1/4 to separately rounded, dehiscent apices; disc flattened above; humeral angles prominent; subbasal swellings nearly obsolete; posterior slope gradual; surface shining, densely but shallowly rugose-punctate, moderately densely clothed with short, fine, suberect silvery setae (these somewhat more densely arrayed at posterior 1/5), interspersed with fewer longer, more robust, erect black setae. Metaventrite: Not particularly convex; surface densely, shallowly and finely rugulosepunctate laterally; densely vested with long, fine, silvery setae anteriorly and laterally. Abdomen: Shining, surface densely but superficially punctate; vestiture moderately dense, composed mostly of reclinate, whitish setae; ventrite 5 with posterior margin broadly, arcuately emarginate; ventrite 6 rather broad, sides oblique, hind angles gently rounded, posterior margin feebly emarginate. Aedeagus: Tegmen not sagittate.

Variation. Length ranges from 5–8 mm. Females have abdominal ventrite 5 with the posterior margin transverse, and ventrite 6 with the hind margin rounded. Colyphus martinezi , like some other members of the genus, exhibits a remarkable range of chromatic morphs within populations ( Figs. 18–25 View Figs ).

Etymology. I am pleased to name this species for Eric Antonio Martinez, co-collector of the type, good friend, able guide, and Oaxacan endemic.

Distribution. Known from the Sierra Madre de Oaxaca, Oaxaca, Mexico.

Biology. Specimens have been collected on thorn and by beating vegetation in mixed tropical deciduous/oak and oak-pine forest at middle elevations. Adult emergence and activity appear to coincide with the advent of the rainy season in early summer.

Diagnosis. Colyphus martinezi is most similar to Colyphus prolatus Ekis , which has been collected in the Sierra Sur of Oaxaca and is not currently known to be sympatric with the new species. They both lack protibial carinae, and males share the non-sagittate condition of the tegmen. Colyphus martinezi specimens tend to be smaller than those of C. prolatus ( 5–8 mm vs. 8–10 mm); they have the antennal club uniformly dark rather than testaceous, the humeri more salient, and the elytra distinctly less elongate.

Discussion. Specimens of C. martinezi displaying the most colorful or variegated elytral patterns are invariably female—a phenomenon I have noted with two other Mexican Colyphus Spinola species. Although one member of the genus ( Colyphus strongylioides Ekis ) is known to mimic a protected coleopteran model ( Ekis 1977), it should not be presumed that color polymorphism in the genus reflects mimetic resemblance to multiple aposematic models, since many of these color morphs do not have any obvious similarity to chemically protected species. Furthermore, polymorphic Colyphus may far outnumber all other insects of their size that are out and active in a particular microhabitat (personal observation), thus violating the (rare) mimic to (common) model ratio theoretically required for the evolution and maintenance of Batesian mimicry. I suggest that a more likely explanation for polymorphism in Colyphus is socalled apostatic selection, which favors the evolution of divergent or rare color morphs ( Bond 2007; White and Kemp 2016). Because insectivorous predators (birds and lizards) can develop a search image for palatable, commonly encountered prey, there is a selective advantage to potential prey animals for expression of color combinations and patterns that violate the memorized image. As for the existence of sex-linked color polymorphism in Colyphus , the phenomenon might be explained by differences in the ecology of males and females, or, alternatively, by the possible role of color in mate selection. These speculations may be of interest to future researchers.