Sphenarium minimum Bruner, 1906

Sanabria-Urbán, Salomón, Song, Hojun, Oyama, Ken, González-Rodríguez, Antonio & Castillo, Raúl Cueva Del, 2017, Integrative taxonomy reveals cryptic diversity in neotropical grasshoppers: taxonomy, phylogenetics, and evolution of the genus Sphenarium Charpentier, 1842 (Orthoptera: Pyrgomorphidae), Zootaxa 4274 (1), pp. 1-86 : 36-37

Sphenarium minimum Bruner, 1906

(http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:36988)

Sphenarium affine Bruner, 1906

Description. External morphology ( Figs. 8 G, H; 9O, P): total body length ranging from 23.67 to 28.57 mm in females and 18.05 to 24.89 mm in males; antennae filiform, slightly shorter in females or notably longer than head and pronotum together in males; head subtriangular-elongated slightly longer than wide in females or conical notably longer than wide in males, with oval eyes in both sexes; fastigium moderately elongated, nearly half the length of interocular space in both sexes; tegmina spatula-like in both sexes; subgenital plate of males rounded moderately developed posteriorly; dorsal ovipositor valves lanceolate, notably elongated towards the apex. Male genitalia: bridge of epiphallus as long as the length of lateral plates in most cases ( Fig. 12 J-I). Ectophallus in dorsal view ( Fig. 12 J-II) with lateral borders of ramus strongly concave; basal emargination of cingulum moderately developed; interspace between apodemal plates of cingulum moderately open. Ectophallus in posterior view ( Fig. 12 K) without a conspicuous sclerotized hollow in the sheath; inflections of supraramus moderately developed with distal margins laterally directed in most cases; valves of cingulum notably small, triangular and slightly developed posteriorly ( Fig. 12 K, L). In lateral view of endophallus ( Fig. 12 J-III) pseudoarch elongated loosely joined the valves of cingulum; aedeagal valves medium sized with smooth ventral margins and moderately rounded in the apex, without apical spine ( Fig. 12 K, L); aedeagal valves and sclerites together about 1 ¼ fold the length of dorsal inflections of endophallic apodemes.

Colouration. Ground colours vary from green, yellow or brown. Body uniformly coloured or with the following colour traits: antennae and fastigium frequently brown; lateral postocular bands frequently present, narrow and yellow; dorsomedial line generally absent, if present very narrow almost restricted to the abdomen, whitish, yellowish or pinkish; dorsal shades frequently absent, if present very narrow in head and thorax, wider in the dorsal portion of abdomen, light to dark brown; lateral shades often absent, if present very narrow, black or dark brown, almost restricted to head and abdomen; lateral bands of blotches not evident; ventral bands of pronotum often absent, if present very narrow and yellowish; mesonotum partially or entirely black; lateral whitish blotches of 1st abdominal segment sometimes evident; in most cases hind femora uniformly coloured, sometimes with lower medial area whitish or yellowish and brown knees; hind tibia frequently yellow or pale orange.

Diagnosis. S. minimum closely resembles S. planum , S. purpurascens , S. tarascum sp.n., and S. zapotecum sp.n. in both external and genital morphology. Externally S. minimum only differs from the former two species by its more elongated head (in both sexes) and its lanceolate and more notably elongated dorsal ovipositor valves. Nevertheless, more conspicuous differences exist between male genital structures of all these species. Sphenarium minimum differs from these species by the following combination of male genital traits: ectophallus with lateral borders of ramus notably concave, valves of cingulum triangular and notably small, medium-sized aedeagal valves and moderately rounded in the apex without apical spine, and aedeagal valves and sclerites about 1 ¼ fold the length of dorsal inflections of endophallic.

Distribution. This species is distributed in elevations ranging from approximately 1000 to 1596 m a.s.l. in the outer slope of southern portion of the Sierra Madre Oriental in Veracruz, Mexico ( Fig. 7 A).

Material examined. S. minimum : lectotype m ( Fig. 8 G) from Mexico: Veracruz, Jalapa, XII (O.W. Barrett); S. affine : lectotype m ( Fig. 8 H) from Mexico: Veracruz, Orizaba, XI-1887 (L. Bruner). Designation: Rehn and Hebard (1912) and location: ANSP for both type specimens. We examined only the external morphology of this type material. Additional material: 7 m, 5 f, from Jalapa (L76); 2 m from Orizaba (L292), 35 m, 26 f, from 12 adjacent localities in Veracruz (Appendix Table 5).

Taxonomic discussion. Bruner (1906) originally described this species apparently based on a single male from Jalapa, Veracruz. Bolivar (1909) and Hebard (1932) recognized S. minimum as a valid species. Particularly, the later author proposed a closer relationship between S. minimum , S. histrio and S. mexicanum mainly based on their head morphology. Boyle (1974) also identified differences in head morphology and colouration patterns between S. minimum and S. purpurascens . However, this author only recognized the former taxon as a subspecies of the later, S. purpurascens minimum , principally based on the similarity between their epiphallic and ectophallic structures. Recently, Pedraza-Lara et al. (2015) and Sanabria-Urbán et al. (2015) proposed again the re-establishment of S. minimum as valid species based principally on genetic evidence. In this study we found that despite the notable similarity in the male genitalia between S. minimum and S. purpurascens the former taxon shows a unique combination of external and male genitalia characters, a well-supported monophyly ( Fig. 2 ), and a well-separated geographic distribution from S. purpurascens . All these lines of evidence support the recognition of S. minimum as a valid species.

Sphenarium affine was only briefly described by Bruner (1906) apparently based on one female and male from Orizaba, Veracruz. Originally, Bruner (1906) recognized a close relationship between S. affine and S. minimum , only differentiating the former from the later in highly variable traits of head morphology. Later S. affine was synonymised within S. marginatum ( Hebard 1932) , despite the notable external differentiation between both taxa. Posteriorly, Boyle (1974) synonymized S. affine within S. p. minimum . In this study we examined several specimens collected in type localities of S. minimum and S. affine ; which were practically similar among them in their male genital morphology. Therefore, we also recognise S. affine as a synonym of S. minimum .

Figures

FIGURE 2. Bayesian phylogeny of Sphenarium based on a concatenated analysis of 2527 nucleotide positions from five loci and 145 terminals (129 ingroup and 16 outgroup terminals). Higher-level phylogenetic relationships are shown on left-top box and ingroup relationships are magnified outside. Voucher and locality identifier numbers of the analysed specimens are indicated in bold characters in terminals names, except for those cases in which genetic information was retrieved from the GenBank. Different branch colours highlight the three mayor clades within the genus (brown, Clade 1; red, Clade 2; and purple, Clade 3). Different colours of the Sphenarium terminals represent the 17 taxa identified during the morphologic analysis. Black circles behind the nodes indicate PP values ± 95 %. For some important nodes we also showed the PP values in bold numbers. Black bottom bars in all cases are equal to 0.03 substitutions per site.

FIGURE 7. Geographic distribution of Sphenarium species. Numbers within parenthesis in front of taxa names indicate the number of identified morphotype within the species. White surrounded areas and upper case abbreviations denote the Mexican biogeographic provinces. AC, Altos de Chiapas; AL, Altiplano Sur; BRB, Balsas River Basin; GMC, Gulf of Mexico Coast; MVB, Mexican Volcanic Belt; PC, Pacific Coast; SMOC, Sierra Madre Occidental; SMOR, Sierra Madre Oriental; SMS, Sierra Madre Sur; SO, Soconusco; and SOX, Sierra de Oaxaca.

FIGURE 8. Type specimens of S. purpurascens: lectotype m (A) and paralectotype f (B); S. planum: lectotype m (C) and paralectotype f (D); S. macrophallicum: holotype m (E) and allotype f (F); S. minimum lectotype m (G); S. affine lecototype m (H) (Scale bars = 1 cm).

FIGURE 12. Male genital structures of S. tarascum sp. n. holotype (A – C); S. planum (D – F); S. macrophallicum paratype # 234 (G – I); and S. minimum (J – L). For all taxa left squares show epiphallus (I) and ectophallus (II) in dorsal view, and endophallus in lateral view (III); meddle squares show ectophallus in posterior view; and right squares show a close up of ectophallus in lateral view (Scale bars = 1 mm).