Introduction

An extensive review of Mexican Orthoptera lists 920 specific or subspecific taxa representing 274 genera (Barrientos-Lozano 2004). Zárate-Torres & Barrientos-Lozano (2005) and Barrientos-Lozano et al. (2008) studied the Orthoptera, Acridoidea inhabiting “El Cielo Biosphere Reserve” in northern México, listing 41 species in a preliminary check list; Torres-Acosta & Barrientos-Lozano (2006) reported 61 species of Orthoptera occurring at the “Natural Protected Area Altas Cumbres”, Victoria-Tamaulipas. In a recent Photographic Guide of Mexican Orthoptera, Fontana et al. (2008) listed 651 species representative of 250 genera.

Within the Orthoptera, the Subfamily Melanoplinae constitutes the third largest subfamily of Acrididae, with more than 900 species around the world. This subfamily has its largest number of species in North America and is dominated numerically in number of species by the genus Melanoplus Stål. This genus includes more than 230 species and represents more than 60% of all Melanoplinae in this continent (Litzenberger & Chapco 2003). Amédégnato et al. (2003) reported ∼330 species of Melanoplinae for North America, ∼235 for South America and about 80 species for Central America.

Regarding Mexican Melanoplinae, Barrientos-Lozano (2004) estimated that 27 genera representing 119 species occur in México; while Fontana et al. (2008) quoted 102 taxa and 25 genera. These figures do not incorporate two new genera and 21 new species described by Otte (2007).

Recent important contributions to the systematics of Mexican Melanoplinae have been made by Otte (2007), Otte & Cohn (2002), Fontana & Buzzetti (2007) and Ciglianao & Otte (2003a, b). However, information on distribution and ecology of Mexican endemic species is very limited, to the extent that some taxa, e.g., Phaedrotetix litus and P. valgus, have been reported as critically endangered ( www.zipcodezoo.com/Animals/critically_endangered) (08/24/2006); an additional constraint is that very often original descriptions are not useful in separating species.

This paper aims to provide new information on geographic distribution of the Orthoptera, Melanoplinae of northeastern México. For some taxa molecular analyses were performed to support morphological separation; description of a new species is also provided.

Materials and Methods

Orthoptera: Melanoplinae were collected in northeastern México (Fig. 1), in the States of Coahuila, Nuevo León, Tamaulipas and San Luis Potosi, from 2000 to 2008. Specimens were collected using an entomological net or by hand, then killed with either ethyl acetate or potassium cyanide; to preserve original colors adults were eviscerated following the technique of Rosas-Costa (1966). Specimens were pinned, labeled and identified. Morphological characters, original descriptions (Scudder 1897; Saussure 1893–1899; Hebard 1917, 1919; Cohn & Cantrall 1974; Descamps 1975; Capinera et al. 2000, 2004; Otte 2007; Fonta & Buzzetti 2007; Cigliano & Otte 2003a, b) Orthoptera Species File-2 (OSF2), and online resources, when available, were used to identify species. Field photographs were taken with a Sony DSC-F707 Digital Camera; measurements and laboratory images were taken with a Motic Stereomicroscope, Model 43-FBGG-C, 3.0 mp (2048 × 1536) and a Carl-Zeiss stereoscope Discovery V12. Dorsal view measurements: body length (head vertex to tip of hind femora), hind femora length and tegmina length; pronotum length, dorsal view. All measurements taken at 10×.

Depositories: IB-UNAM collection (Instituto de Biología-Universidad Nacional Autónoma de México) and L. Barrientos collection.

Molecular analyses were used to confirm that some taxa, particularly Phaedrotettix, Mexitettix and Huastecacris, belonged to the species and genera assigned using morphological characters.

Ethanol-preserved or dry specimens were used for genomic DNA extractions. With a Qiagen kit (QIAGEN Inc., Valencia, CA) we obtained genomic DNA from the right hind femur of grasshoppers. From these DNA samples we developed AFLP molecular markers (Vos et al. 1995). AFLP were obtained using components from various commercial kits. Digestion of genomic DNA by EcoRI and MseI and ligation of oligonucleotide adaptors were performed in a single reaction. Each reaction contained approximately 127.73 ng/µL of DNA. Preselective PCR amplification was performed using the Applied Biosystems AFLP kit (Applied Biosystems, Foster City, California). All samples were stored at 4 °C following amplification. The amplified product was diluted 20-fold using 15nM Tris-HCl buffer (pH 8.0) containing 0.1 mM EDTA. For selective PCR amplification of restriction fragments, we used already prepared custom primers for recognition of EcoRI and MseI adaptors. Fragments were visualized using fluorescent dyes attached to the 5′ end of each EcoRI selective amplification primer, with no modification made to the MseI primer.

Table 1.

Melanoplinae of Northeastern México, species list, relative abundance and calculation of Simpson's biodiversity index.

AFLP markers were analyzed using capillary electrophoresis in a 3100 Genetic Analyzer from Applied Biosystems (Foster City, California) and visualized using GeneMapper. Markers were normalized using the sum of signal method. Markers with a dye signal larger than 100 luminescent units were considered as present. PAUP 4.0 (Swofford 2003) was used to generate a neighbor-joining tree (Saitou & Nei 1987). The adequateness of the number of AFLP markers and the number of individuals used to generate the neighbor-joining tree generated was assessed using SESim values (Medina et al. 2006).

Simpson's index (D) was used to assess Melanoplinae diversity. Simpson's index describes the probability that a second individual drawn from a collection area will belong to the same species as a first. Simpson's biodiversity index (1-D) describes the probability of collecting a second individual from a different species than the first at a given location; these values were obtained using Southwood's methodology (1984).

Results and Discussion

A total of 1787 specimens of Melanoplinae were collected, representing 13 genera and 33 species (Table 1). Four species are considered as new records: Melanoplus anzonae Scudder, 1878; M. bivittatus (Say, 1825); M. regalis (Dodge, 1876); M. sanguinipes sanguinipes (Fabricius, 1878); twenty are endemic to Mexico (Table 2, see p. 45) and a new species is described: Huastecacris fariensis n. sp. (Figs 3A-D). Novel information on collection sites, geographic distribution and relative abundance of poorly known endemic species is provided (Table 2).

Fig. 1.

Map of México showing the northeastern region, where specimens were collected. COAH: Coahuila, NL: Nuevo León, TAM: Tamaulipas, SLP: San Luis Potosi.

The material studied represents 45% of the genera and 24% of the Melanoplinae species reported for Mexico. However, the number of species occurring in the northeastern region maybe considerably higher than this since additional species have been described (Otte 2007). Our results agree with those reported by Barrientos-Lozano (2004), Fontana & Buzzetti (2007) and Otte (2007), regarding abundance and diversity of this group in northeastern México. Some taxa (e.g., Agroecotettix modestus modestus Hebard, 1922; Huastecacris Fontana & Buzzetti, 2007 and Mexitettix Otte, 2007) are known only from northeastern México; other taxa (such as Melanoplus Stål, 1872) are very diverse and abundant in northeastern and central Mexico and represented by only a few taxa in the south, as pointed out by Fontana and Buzzetti (2007).

Each of a good number of endemic species are known only from their type locality. We have done extensive collection in northeastern México and some of the species there are confined to certain areas of the eastern mountain range (Sierra Madre Oriental), i.e., A. m. modestus; Melanopls regalis; M. sanguinipes sanguinipes; M. scitulus Scudder, 1897; Mexitettix jocari Otte, 2007; Mexitetti ricuchuri Otte, 2007; Mexitetti simuchi Otte, 2007 and Pedies cerropotosi Fontana & Buzzetti, 2007 (see Table 2).

Hustecacrsi zenoni Fontana & Buzzetti, 2007 is the only species of this genus that occurs in the mountains surrounding Cd. Victoria; however, its distribution extends south of Tamaulipas towards Llera, Mante, Gómez Farías, Ocampo and Tula, where it occurs in sympatry with H. fariensis n. sp. This latter species extends its distribution from South Tamaulipas to East San Luis Potosi and Northern Hidalgo. H. truncatipennis is widely distributed in northeastern Mexico, even so, it does not occur sympatrically with H. zenoni or H. fariensis.

Melanoplus scitulus was known from Mount Alvarez, San Luis Potosi (type locality); this is one of the dominant species in the Natural Protected Area “Cerro El Potosí”, Nuevo León, where it has been collected between 3600 to 3730m; Cerro Potosi is considered the highest peak of the eastern mountain range (Sierra Madre Oriental) in northeastern, México.

Necaxacris moctezumae Roberts (Figs 4A, B) is known from Tamazunchale, San Luis Potosi (type locality) and Veracruz (Descamps, 1975); this species extends its known distribution to northern Tamaulipas and Nuevo León (Table 2). The five species of Phaedrotettix reported are widely distributed in northeastern, Mexico. The occurrence in Mexico of M. arizonae, M. bivittatus, M. regalis and M. sanguinipes sanguinipes is confirmed.

Melanoplus Stål, 1873 and Phaedrotettix Scudder, 1897 were the most diverse genera encountered, with 13 and five species, respectively (Table 1).

The most commonly collected species were Phaulotettix compressus (Scudder, 1897) (231 specimens), Phaedrotettix violai Fontana & Buzzetti, 2007 (229), H. zenoni (188), Phoetaliotes nebrascensis (Thomas, 1872) (161), Melanoplus flavidus Scudder, 1878 (110) and Huastecacris truncatipennis Fontana & Buzzetti, 2007 (109).

Species poorly represented, with ten or less individuals, were as follows: A. m modestus (3 individuals only); Melanoplus arizonae (8); Melanoplus bivittatus (5); Melanoplus gladstoni Scudder, 1897 (3); Melanoplus regalis (1); Mexitettix jocari Otte, 2007 (5), Mexitettix ricuchuri Otte, 2007; (3), Mexitettix simuchi Otte, 2007 (4); Phaedrotettix angustipennis Scudder, 1897 (6) and Phaedrotettix valgus Scudder, 1897 (10).

Phaedrotettix gracilis (Brunner, 1908) (Figs 6A-C) was previously known only from its type locality in south Tamaulipas; its distribution is now seen to extend northwards to Nuevo León and Coahuila; it was collected between 61 to 1700 m (Table 2).

Fig. 2.

AFLP tree for some species of northeastern Mèxico Melanoplinae.

Fig. 3.

Huastecacris fariensis n. sp. A. Female. B. Male supra-anal plate dorsal view. C, D. Male left cercus lateral view.

Phaedrotettix litus Hebard, 1917 was listed as critically endangered in 2006 ( www//zipcodezoo.com/Animals/critically_ endangered.asp); this species was not abundant (see Table 1) and seems to be confined to certain mountainous localities of Nuevo León and Tamaulipas (Table 2). The “Natural Protected Area Altas Cumbres”— municipality (county) of Victoria, Tamaulipas and Horsetail Falls, Santiago, Nuevo León, where P. litus has been collected, are characterized by their biological diversity, geological formations and endemisms; both locations are subject to conservation by decree since 1997.

Simpson's Index (D) was estimated at 0.07, indicating the probability of picking up a second individual that belongs to the first species collected in a sample site, is 7%; Simpson's Biodiversity Index (1-D) = 0.93, i.e., the probability of collecting any of the Melanoplinae species at a given collection site is 93%. Simpson's Index varies from 0 to 1, 1 being the highest biodiversity; therefore it may give an indication of the high biodiversity of this group in northeastern Mexico.

The neighbor-joining tree based on AFLP markers (Fig. 2) shows Melanoplinae grouped according to morphological separation. Huastecaris fariensis n. sp., H. truncatipennis and H. Zenoni cluster together; these three species belong to the tribe Conalcaeini, agreeing with the assignment that Cohn & Cantrall (1974) and Fontana & Buzzetti (2007) have given for these taxa. M. simuchi (Fig. 5A-C) aligned close to P. litus; these two genera may be hard to separate based on morphological characters, particularly if one is not very familiar with the numerous taxa from both genera.

Illustrations are provided for N. moctezumae, P. gracilis and M. simuchi; for the first two taxa no recent information was available.

A good number of endemic taxa reported here are poorly known because they are not economically important. Scudder (1897) when describing the genus Phaulotettix (P. compressus) reckoned this as a “good-for-nothing; terric, grasshopper”. Most taxa of Agroecotettix, Huastecacris, Mexitettix, Phaedrotettix and Phaulotettix, live in low numbers in canyons or at the top of mountains. Some of these species have probably survived as relict populations. Most species treated here occur along the eastern Sierra Madre in northeastern Mexico: “Natural Protected Area Altas Cumbres”, El Cielo Biosphere Reserve, Horsetail Falls, La Huasteca and other isolated mountains that are the habitat of these, and certainly, many other endemic and undescribed species.

Conclusions

New information on collection sites, geographic distribution and abundance is provided for 13 genera and 33 species of Melanoplinae occurring in northeastern Mexico. This represents 45% of the genera and 24% of the Melanoplinae species known for Mexico. Four of the 33 species treated are new records for Mexico. Huastecacris fariensis n. sp. is described and illustrated in addition to two species of this genus described previously by Fontana and Buzzetti (2007).

Mexican endemic species of Melanoplinae are restricted to certain localities of the eastern mountain range (top of mountains, canyons, remote areas) all of them under some status of protection (Biosphere Reserves, Natural protected Areas, National Parks, Natural Monuments).