Perixerus obscurus, Fontana & Mariño-Pérez & Sanabria-Urbán & Woller, 2017

Fontana, Paolo, Mariño-Pérez, Ricardo, Sanabria-Urbán, Salomón & Woller, Derek A., 2017, Studies in Mexican Grasshoppers: Three new species of Dactylotini (Acrididae: Melanoplinae) from Mexico and a review of existing conspecifics with comments on their geographical distributions, Zootaxa 4337 (3), pp. 301-343 : 330-334

Perixerus obscurus sp. nov.

( Figs. 1C,D & 25–29 )

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:498235

Diagnosis. This species looks fairly different from P. squamipennis in terms of coloration, with the hind legs particularly distinct due to the orange that is often mixed in. In terms of terminalia, the external male components are more similar to P. squamipennis while the external female components resemble those of P. triqui sp. nov. The internal genitalia of the male are fairly unique among conspecifics. Male: general coloration dark compared to P. squamipennis , pronotum more rugose with metazona that is often longer, absence of median carina, and larger tegmina cells. Furculae vestigial with short gap between, supra-anal plate subtriangular overall with slightlyrounded apex and relatively shorter than conspecifics, and with shallow, median groove that extends apically for approximately 1/3rd the total length, cerci relatively short and curved gently inwards. Phallic complex with the following unique characters: lophi of epiphallus more prominent and bent further anteriorly than conspecifics, rami sharply angled towards posterior, and sheath of aedeagus most elaborate with two shovel-shaped lobes enveloping apices of dorsal valves of aedeagus and extending further posteriorly. Valves of aedeagus relatively simple compared to conspecifics, with dorsal valves quite small and weak compared to ventral valves, which widen apically and have bulbous, hollow structures emerging ventrally. Female: looks different, in terms of general appearance, color, and other assorted characters; in particular: the position of the sulcus on the pronotum, the larger reticulated cells of the tegmina, and the overall color pattern of the body, especially that of the abdomen. Additionally, the ventral valves of ovipositor are without teeth.

Coloration. Antennae dark brown to blackish, often lightly colored towards the base. Pronotum dark brown to pale blue; tegmina light brown with contrasting dark reticulation. Eyes pale orange to red. Head, fore and middle legs bluish to blackish; abdominal tergites blackish-brown with yellowish posterior margin; hind femur with upper and lower margin yellowish to orange and blackish medial area on external surface; hind tibia blackish with basal portion orange to reddish. Ventral portion of the body yellowish. ( Figs. 1C,D , 25 , 28 ).

Pronotum and Tegmina. In most cases, pronotum often with raised metazona in lateral view, rugose both in prozona and metazona; median carina not detectable, except in nymphs; metazona about 4/9 of total length of pronotum; pronotum from above with almost parallel sides in males, more diverging in females; posterior pronotal margin widely rounded, partly emarginated; tegmina often reaching the end of 2nd abdominal tergite, meeting on dorsum, reticulation with bigger cells than in P. squamipennis ( Figs. 25 & 28 ).

Terminalia: Male, external. In most examined specimens furculae vestigial with short gap between. Supraanal plate subtriangular with slightly rounded apex and shorter than in P. squamipennis and P. triqui ; lateral sides sinuous and with shallow, median groove that extends apically for approximately 1/3rd the total length. Cerci relatively short and similar to P. squamipennis : wider at base and narrowing in middle with rounded apices; gently curving inwards beginning around midway point. Subgenital plate short with pointed apex ( Fig. 26A,B ). Internal phallic complex: overall, typical for a melanopline, with the following unique characters: Epiphallus: ancorae relatively short, subtriangular, and curve slightly inwards; lophi prominent and most robust of conspecifics, subrectangular, and typically bent slightly anteriorly; post-epiphallic lobe moderately wrinkled, similar to conspecifics, and covered in raised microstructures ( Figs. 26C,D & 27A,B ). Ectophallus: rami prominent and resembling a stretched-out “N” shape that is angled posteriorly more sharply than in conspecifics, basal portion wider than conspecifics, and extending well below valves of aedeagus. Sheath of aedeagus comprised of two halves, each with two lobes of similar size that are attached to apical 1/4th of rami with each side extending upwards to the upper dorsobasal region of the dorsal valves of aedeagus, meeting only occasionally along ventral margins; dorsoapical portion of each lobe also extends posteriorly along dorsal valves, covering them completely, and forming shovel-like structures that taper to rounded points and almost reach apices of ventral valves of aedeagus; covered in raised microstructures resembling those on the post-epiphallic lobe ( Figs. 26C,D & 27A,C,D ).

Endophallus: arch of aedeagus weakly developed. Dorsal valves of aedeagus do not meet flexures, are fused for most of their length with a short separation towards apex, and shorter than ventral valves, which are often up to 1/ 3rd longer; sheath of aedeagus essentially covers these relatively weak valves, extending beyond their apices to give the appearance that it is the valves themselves that are projecting posteriorly for some distance. Ventral valves of aedeagus meet flexures and are up to1/3rd longer than dorsal valves; apical ½ about twice as wide with relatively large, bulbous, hollow regions appearing ventrally on both sides as the valves widen ( Figs. 26C,D & 27A,C,D ). Female, external: as in P. squamipennis and P. triqui : supra-anal plate subtriangular and cerci relatively small and subconical; dorsal valves of ovipositor with small teeth along dorsobasal margin; ventral valves of ovipositor without teeth ( Fig. 29 ).

Male measurements (in mm) (n=6) ( Table 1): Body length 19.92–21.06 (20.54 ± 0.48); pronotum length 5.17–5.66 (5.46 ± 0.16); prozona length 2.46–2.79 (2.66 ± 0.11); metazona length 2.38–2.97 (2.80 ± 0.22); hind femur length 11.12–11.46 (11.36 ± 0.12); and tegmina length 4.81–5.19 (5.00 ± 0.14). Female measurements (in mm) (n=5) ( Table 1): Body length 23.19–27.83 (25.62 ± 1.70); pronotum length 6.72–8.08 (7.22 ± 0.63); prozona length 3.36–4.20 (3.76 ± 0.31); metazona length 3.03–3.88 (3.46 ± 0.41); hind femur length 12.64–15.32 (14.02 ± 0.1.05); and tegmina length 5.15–7.16 (6.11 ± 0.76).

Etymology. This species is named for its generally dark appearance and the fact that it was hidden within museum specimens of P. squamipennis . In fact, the Latin word “ obscurus ” not only means dark, but covered as well.

Holotype. Male ( Figs. 25–27 ), México, Oaxaca, San Juan Atepec. 17.43977398, -96.51481697 (WGS84). 2,703 m.a.s.l. 16-X-2015. (S. Sanabria-Urbán); # M024-L56 ( Fig. 25 ). (CNIN-UNAM)

Additional Type Material. 14 paratypes (7 adult males and 7 adult females). 5 males and 4 females same locality as holotype (CNIN-UNAM). 1 male and 1 female México, Oaxaca, Ixtlán. -96.48401398; 17.32114197. 1926 m a.s.l. (17-X-2015) Legit S. Sanabria-Urbán & L. Laroo # M028-L40. ( CPF) 1 female Oaxaca, Km 40 Highway #175 Oaxaca-Guelatao . 17°18’35’’ N; 96°32’18’’ W. 1746 m a.s.l. (4-XII-1979) Legit G. Ortega-Leon. ( CPF) México, Oaxaca, Santa Maria Jalteanguis. -96.52176901; 17.35841897. 2299 m a.s.l. (14-X-2015) Legit S. Sanabria-Urbán. 1 male and 1 female (in ethanol) from México, Oaxaca, Llano de las flores. -96.503902; 17.446855. 2866 m a.s.l. (14-X-2015) Legit S. Sanabria-Urbán & L. Laroo. ( TAMUIC)

Geographic distribution. This species is apparently isolated geographically from its congeners and is confined to the inner slope of the Sierra Norte de Oaxaca mountain range, in elevations ranging from 1,746 to 2,866 m.a . s.l. in Oaxaca, Mexico ( Fig. 36 ).

Figures

FIGURE 1. LIVE SPECIMENS OF: A. Dasyscirtus olivaceus, MATING PAIR; B. Perixerus squamipennis, MATING PAIR; C. P. obscurus sp. nov., MALE; D. P. obscurus sp. nov., FEMALE NYMPH; E. P. triqui sp. nov., MALE; F. P. triqui sp. nov., FEMALE.

FIGURE 25. Perixerus obscurus sp. nov. HOLOTYPE MALE SPECIMEN: A. HABITUS, LEFT LATERAL VIEW; B. THORAX, DORSAL VIEW.

FIGURE 26. Perixerus obscurus sp. nov. HOLOTYPE MALE SPECIMEN: EXTERNAL GENITALIA: A. LEFT LATERAL VIEW; B. DORSAL VIEW; INTERNAL GENITALIA (DRY): C. LEFT LATERAL VIEW; D. DORSAL VIEW.

FIGURE 27. Perixerus obscurus sp. nov. HOLOTYPE MALE SPECIMEN: INTERNAL GENITALIA (KOH-CLEARED): A. COMPLETE PHALLIC COMPLEX, DORSAL VIEW; B. EPIPHALLUS, DORSAL VIEW; C. ECTOPHALLUS / ENDOPHALLUS, LEFT LATERAL VIEW; D. ECTOPHALLUS / ENDOPHALLUS, DORSAL VIEW.

FIGURE 28. Perixerus obscurus sp. nov. PARATYPE FEMALE SPECIMEN: A. HABITUS, LEFT LATERAL VIEW; B. THORAX, DORSAL VIEW.

FIGURE 29. Perixerus obscurus sp. nov. PARATYPE FEMALE SPECIMEN: EXTERNAL GENITALIA: A. DORSAL VIEW; B. LEFT LATERAL VIEW; C. VENTRAL VIEW.

FIGURE 36. KNOWN GEOGRAPHIC DISTRIBUTIONS OF Dasyscirtus, Perixerus AND Liladownsia SPECIES INDICATING THE MEXICAN BIOGEOGRAPHIC PROVINCES WHERE THEY ARE RESTRICTED. BRB, BALSAS RIVER BASIN; GM, GULF OF MEXICO COAST; MVB, MEXICAN VOLCANIC BELT; PC, PACIFIC COAST, SMS, SIERRA MADRE DEL SUR; SO, SIERRA DE OAXACA.