Sphenarium planum 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 : 32-33

Sphenarium planum Bruner, 1906

(http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:36998)

Description. External morphology ( Figs. 8 C, D; 9K, L): total body length ranging from 21.30 to 29.04 mm in females and 18.29 to 26.24 mm in males; antennae filiform, notably shorter in females or slightly longer than head and pronotum together in males; head subtriangular-compressed, wider than long with spherical eyes in females or subtriangular-elongated moderately longer than wide with oval eyes in males; fastigium notably reduced, less than a half the length of interocular space in females or moderately elongated, nearly half the length of interocular space in males; tegmina spatula-like in both sexes; subgenital plate of males rounded, moderately developed posteriorly; dorsal ovipositor valves lanceolate, moderately elongated towards the apex. Male genitalia: bridge of epiphallus as long as the length of lateral plates in most cases ( Fig. 12 D-I). Ectophallus in dorsal view ( Fig. 12 D-II) with lateral borders of ramus convergent slightly rounded; basal emargination of cingulum notably reduced; interspace between apodemal plates of cingulum widely open. Ectophallus in posterior view ( Fig. 12 E) without a conspicuous sclerotized hollow in the sheath; inflections of supraramus reduced; ramus of cingulum distinctly developed ventrally; valves of cingulum with unique form notably developed posteriorly ( Fig. 12 F). In lateral view of endophallus (12D-III) pseudoarch elongated loosely joined to the valves of cingulum; aedeagal valves slender, long, with smooth ventral margins and moderately rounded in the apex without apical spine; aedeagal valves and sclerites together about 2 ½ fold the length of endophallic apodemes.

Colouration. Ground colours vary from green, beige, brown or grey, yellow or brown. Body uniformly coloured ( Fig. 9 L) or with the following colour traits: antennae often yellow; fastigium frequently brownish to reddish; lateral postocular bands yellow; dorsomedial line frequently absent, if present very narrow, restricted almost entirely to the abdomen and yellowish; dorsal shades black, grey or brown, frequently less evident in head and pronotum; lateral shades frequently absent, if present very narrow and restricted to the head; lateral bands of blotches sometimes evident and yellowish; ventral bands of pronotum if present yellowish, wide or narrow; mesonotum partially or entirely black; lateral blotches of 1st abdominal segment whitish; hind femora frequently with upper medial area dark green and lower medial area yellow; frequently knees of hind femora laterally black, dorsally brownish; frequently hind tibia yellow or brown.

Diagnosis. Externally this species closely resembles S. purpurascens and S. rugosum . Generally, females of S. planum have smaller antennae than any other of its congeners. Moreover, when present, the yellow colourations of the lateral bands of blotches and the medial area of the hind femora of S. planum distinguish it from S. purpurascens . On the other hand, the male genitalia of S. planum more closely resemble that of S. rugosum , and S. crypticum sp.n., which also lack the apical spine of aedeagus. However, S. planum differs from all these species by the following combination of male genital traits: lateral borders of ramus convergent slightly rounded, basal emargination of cingulum notably reduced with a wide open interspace between the apodemal plates of cingulum, inflections of supraramus reduced, ramus of cingulum is distinctly developed ventrally, aedeagal valves moderately rounded in the apex without apical spine, and aedeagal valves and sclerites relatively long and slender.

Distribution. This species is apparently restricted to the Tehuacan valley with sparse records in the surrounding mountain ranges of this valley in Puebla, Oaxaca and Veracruz, Mexico ( Fig. 7 A) in elevations ranging from approximately 1200 to 2095 m a.s.l.

Material examined. Lectotype m ( Fig. 8 C) and paralectotype f ( Fig. 8 D) from Mexico: Puebla, Tehuacan, XI (L. Bruner); designation: Rehn and Hebard (1912); location: ANSP. We could examine only the external morphology of this type material. Additional material: 10 m, 10 f, from the type locality; 45 m, 16 f, from 12 adjacent localities (Appendix Table 5).

Taxonomic discussion. Bruner (1906) originally described this species from two syntypes (a male and female) erroneously specifying Tehuantepec as its type locality rather than Tehuacan as it is labelled in the type material. Bruner also recognised a close relationship between S. planum and S. purpurascens indicating that the former species differed from the latter in its more rotund form and in the absence of lateral carina of pronotum. However, these traits are ambiguous and variable within the genus. Posteriorly, Boyle (1974) identified differences in endophallic morphology between these two species, but he interpreted this differentiation as geographic variation of S. p. purpurascens and/or probable hybridization with S. p. minimum , recognising S. planum only as an intermediate form between these two later taxa. Previously, we proposed the re-establishment of S. planum as valid species mainly based on genetic evidence ( Sanabria-Urbán et al. 2015). In this study we found that S. planum shows a unique combination of male genitalia characters, a well-supported monophyly ( Fig. 2 ), relatively high levels of interspecific genetic differentiation ( Table 3). All these lines of evidence support the recognition of S. planum as a valid species.

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 9. External morphology of S. purpurascens: morphotype 1 m (A) and f (B), morphotype 2 m (C) and f (D), and morphotype 3 m (E) and f (F); S. zapotecum sp. n. holotype m (G) and paratype f # 23 (H); S. tarascum sp. n. holotype m (I) and paratype f # 2 (J,); S. planum m (K) and f (L); S. macrophallicum paratype m # 230 (M) and f (N); S. minimum m (O) and f (P); S. infernalis sp. n. holotype m (Q) and paratype f # 2 (R); S. rugosum morphotype 1 m (S) and f (T) (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).