Sphenarium mexicanum Saussure, 1859

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 : 47-50

Sphenarium mexicanum Saussure, 1859

(http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:37003)

Opomala crassipes Walker, 1870

Sphenarium ictericum Gerstaecker, 1873 Sphenarium bolivari Bruner, 1906

Sphenarium marginatum Bruner, 1906 Sphenarium magnum Márquez, 1962

Description. External morphology ( Figs. 17 B, C, D, E, F, G, H; 18A, B; 15M, N, O, P): total body length ranging from 33.23 to 46.66 mm in females and from 30.99 to 41.58 mm in males. In most cases: antennae filiform to weakly ensiform, slightly shorter in females or 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 females or notably elongated, nearly as long as the interocular space in males; tegmina strap-like in both sexes; subgenital plate of males rounded, moderately developed posteriorly; dorsal ovipositor valves rounded or lanceolate moderately elongated towards the apex. Male genitalia: bridge of epiphallus slightly longer than the length of lateral plates ( Fig. 19 A-I, D-I). Ectophallus in dorsal view ( Fig. 19 A-II,D-II) large with lateral borders of ramus convergent; basal emargination of cingulum notably or slightly developed; interspace between the apodemal plates close. Ectophallus in posterior view ( Fig. 19 B, E) with a conspicuous sclerotized hollow in the sheath notably open; inflections of supraramus notably reduced; valves of cingulum claw-like rather stout ( Fig. 19 A-III, D-III). Ectophallus in lateral view ( Fig. 19 C, F) with valves of cingulum notably (morphotype 1, Fig. 19 C) or moderately (morphotype 2, Fig. 19 F) developed posteriorly, always evident. Endophallus in lateral view ( Fig. 19 A-III, D-III) with a short pseudoarch tightly joined to the valves of cingulum; aedeagal valves very small, tapered in the apex without apical spine; aedeagal valves and sclerites as long as (morphotype 1, Fig. 19 A-III) or about ¾ (morphotype 2, Fig. 19 D-III) the length of dorsal inflections of endophallic apodemes.

Colouration. Ground colours vary from olive green to brown. Body uniformly coloured ( Fig. 15 N) or with the following colour traits ( Fig. 15 M, O, P): antennae black, gray or dark blue; fastigium often blue or black; lateral postocular bands frequently present, narrow and yellowish; dorsomedial line frequently present, wide and yellowish; dorsal shades if present black to dark blue, generally absent in most of the range of the species except in populations in the Isthmus of Tehuantepec ( Fig. 15 O, P); lateral shades often present, black or dark blue; lateral bands of blotches frequently present and reddish; ventral bands of pronotum often present, wide, whitish, rarely bluish; frequently pronotum with white lateral carinas and small stripes and dots in the posterior dorsal margin; mesonotum partially or entirely red; lateral blotches of 1st abdominal segment frequently present and whitish; generally hind femora uniformly coloured with knees laterally black, dorsally bluish; hind tibia light brown to reddish.

Diagnosis. This species is similar to S. histrio and S. totonacum sp.n. in both male genitalia and external morphology. Nevertheless, S. mexicanum clearly differs from other Sphenarium species by the following combinations of male genital characters: ectophallus relatively large, notably conspicuous sclerotized hollow in the sheath, inflections of supraramus notably reduced, and valves of cingulum claw-like, rather stout, notably or moderately developed posteriorly.

Distribution. This species is distributed in elevations ranging approximately from 6 to 1280 m a.s.l. in the southern portion of the Golf of Mexico Cost, the outer slope of the Sierra de Oaxaca and the Isthmus of Tehuantepec in Oaxaca, Veracruz and Tabasco, Mexico ( Fig. 7 B). The morphotype 1 of this species is widely spread across most of the range of the species; whereas morphotype 2 was only observed in a single population near Tehuantepec (L14) ( Fig. 7 B).

Material examined. S. mexicanum : lectotype f ( Fig. 17 B) and paralectotype m ( Fig. 17 C) from Mexico: Litoral du Mexique (M. H. Saussure); designation: Kevan (1960, unpublished results); located: Natural History Museum Geneva ( NHMG), Geneva , Sweden . O. crassipes : holotype m ( Fig. 17 D) from Mexico: Veracruz; designation by monotypy; location: British Museum of Natural History ( BMNH), London , England . S. ictericum : lectotype m ( Fig. 17 E) and paralectotype f ( Fig. 17 F) from Mexico ; designation: Kevan (1962, unpublished results); location: BZM. S. bolivari : lectotype m ( Fig. 17 G) and paralectotype m ( Fig. 17 H) from Mexico: Oaxaca, Salina Cruz , XII-1898 (C.C. Deem); designation: ( Rehn & Hebard 1912); location: ANSP. S. marginatum : lectotype m ( Fig. 18 A) from Mexico: Veracruz, Orizaba, XI and paralectotype m ( Fig. 18 B) from Mexico: Veracruz, Medellin (T. Heyde); designation: ( Rehn & Hebard 1912); location: ANSP. S. magnum : holotype m, allotype f and paratypes (2 m, 2 f), from Mexico: Oaxaca, Santo Domingo, XII-16-1 953 (L. Vázquez); designation: Márquez (1962); location: IBUNAM. For S. bolivari we were able to examine the external and male genital morphology of the paratype; whereas for the remainder taxa we could examine only their external morphology. Additional material: 212 m, 169 f, form 50 Mexican localities (Appendix Table 5).

Taxonomic discussion. Saussure (1859) briefly described S. mexicanum based on an unstated number of male and female syntypes from “Mexico Calida”, probably Veracruz, Mexico ( Saussure 1859). The validity of S. mexicanum remained unchanged until Boyle (1974) ans Kevan (1977) considered this taxon as the subspecies S. mexicanum mexicanum ( Boyle 1974; Kevan 1977). Recently, Pedraza-lara et al. (2015) and Sanabria-Urbán et al. (2015) have proposed the elevation of this taxon at the species level. According to our results, this species is closely related and/or paraphyletic with respect to S. histrio and S. occidentalis sp.n. lineages. However, S. mexicanum clearly differs from these species genetically (CO1 P-distance> 3%) and in male genital structures. Therefore, we also agree in considering S. mexicanum a valid species.

Opomala crasipes was initially described from a single male ( Walker 1870) from Veracruz, Mexico, that was later transferred to the genus Sphenarium ( Kirby 1910) . Later, Uvarov (1925) independently confirmed Kirby’s taxonomic rearrangement and synonymised S. crasipes within S. mexicanum . Considering the type locality and external similarity, we agree in considering S. crassipes as a synonym of S. mexicanum .

Sphenarium ictericum was originally described apparently from a single pair, one male and female, form an unspecified Mexican locality ( Gerstaecker 1873). After its description the taxonomic position of S. ictericum has been variable. In some studies this taxon has been considered as a synonym of S. histrio ( Hebard 1932; Márquez 1962); whereas in others it was considered as a synonym of S. mexicanum ( Bolivar 1904; Boyle 1974; Bruner 1906; Kevan 1977). It is undoubtedly difficult to determine the taxonomic position of S. ictericum without examination of the male genitalia. In fact, we consider that there is a remarkable similarity between this species and S. mexicanum , S. histrio , and S. occidentalis sp.n. Nevertheless, in the absence of further evidence we accept synonymising S. ictericum with S. mexicanum as in the last taxonomic revision of the genus ( Boyle 1974).

Sphenarium bolivari was originally described from two male syntypes from Salina Cruz , Oaxaca ( Bruner 1906). After its description the validity and taxonomic position of S. bolivari has been variable. In some studies this taxon was considered as a synonym of S. histrio ( Hebard 1932; Márquez 1962); whereas in others it was considered as a synonym of S. mexicanum and sometimes as an intermediate from between S. mexicanum mexicanum and S. mexicanum histrio ( Boyle 1974; Kevan 1977). In this study, we observed that the male genitalia of the S. bolivari paralectotype were similar to those of other S. mexicanum specimens. Thus, we agree in considering the former species as a synonym of the latter.

Sphenarium marginatum was initially described based on four specimens ( Bruner 1906) from three localities in Veracruz: one male and female from Cordova, one male from Orizaba and one female from Medellin. After its description S. marginatum was synonymised as S. mexicanum ( Boyle 1974; Kevan 1977). During this study we examined several specimens collected near to the localities of the original description of S. marginatum (L252, L260, L261, L273, L274 and L279; Appendix Table 5); which were similar in their male genitalia to other specimens assigned to S. mexicanum . Therefore, we agree in recognising S. maginatum as a synonym of S. mexicanum .

Sphenarium magnum was originally described based on six specimens from a single locality, Santo Domingo, Oaxaca ( Márquez 1962). The validity and taxonomic position of S. magnum has been variable after its description. This species was considered as an intermediate from between S. m. mexicanum and S. m. histrio , being synonymised with S. m. mexicanum ( Boyle 1974) or S. m. histrio ( Kevan 1977) . Moreover, recently this taxon was proposed as a valid species ( Sanabria-Urbán et al. 2015). During this study, we conducted a more detailed examination of several specimens collected in the type locality of S. magnum and surrounding areas (L14, L246, L250 and L231; Appendix Table 5). These specimens were similar or slightly differed genetically and in their male genitalia from other S. mexicanum individuals. Therefore, here we consider S. magnum as a synonym of S. mexicanum .

Figures

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 15. External morphology of S. rugosum: morphotype 2 m (A) and f (B), morphotype 3 m (C) and f (D); S. crypticum sp. n. holotype m (E) and paratype f # 45 (F); S. borrei m (G) and f (H); S. variabile: morphotype 1 paratype m # 134 (I) and f (J), and morphotype 2 m (K) and f (L); S. mexicanum: morphotype 1 m (M) and f (N), and morphotype 2 m (O) and f (P); S. histrio: morphotype 1 m (Q and S) and f (R and T) (Scale bars = 1 cm).

FIGURE 17. Type specimens of S. variabile: allotype f (A); S. mexicanum lectotype f (B) and paralectotype m (C); O. crassipes holotype m (D); S. ictericum: lectotype m (E) and paralectotype f (F); S. marginatum lectotype m (G) and paralectotype f (H) (Scale bars = 1 cm).

FIGURE 18. Type specimens of S. bolivari: lectotype m (A) and paralectotype m (B); S. histrio holotype m (C) and S. carinatum holotype m (D) (Scale bars = 1 cm).

FIGURE 19. Male genital structures of S. mexicanum: morphotype 1 (A – C) and morphotype 2 (D – F); S. histrio: morphotype 1 (G – I) and morphotype 2 (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).