Acantheremus colwelli Naskrecki, 1997

Piotr Naskrecki, 2000, Katydids of Costa Rica / Vol. 1, Systematics and bioacoustics of the cone-head katydids (Orthoptera: Tettigoniidae: Conocephalinae sensu lato)., Philadelphia, PA: The Orthopterists Society at the Academy of Natural Sciences of Philadelphia, : 46

Acantheremus colwelli Naskrecki, 1997

Common name: Colwell’s horned katydid

Figs. 10 A-G, 36C, 43D-E, 54D-E, Map 4

1997 Naskrecki Trans. Amer. Entomol. Soc. 123(3): 152;

type locality: Costa Rica: Guanacaste Prov., Estación Pitilla, 9 km S Santa Cecilia, elev. 700 m; type depository: Instituto Nacional de Biodiversidad, San José, Costa Rica – holotype male

1999 Naskrecki and Otte, Illustr. Cat. Orthop. I (CD ROM) >> holotype illustrated

Diagnostic description.— Body small, with wings in both sexes slightly surpassing apices of hind femora ( Figs. 10 A, 36C). Fastigium of vertex about 2.5-3 times as long as eye diameter; triangular when viewed in front; apex bifurcated ( Figs. 10 B-C). Pronotum granulate; both anterior and posterior margins straight; lateral lobe of pronotum 1.8 times longer than high. Male stridulatory apparatus well developed; stridulatory file straight, 1.15 mm long, 0.17 mm wide, with 358 very closely spaced, lamelliform teeth ( Figs. 43 D-E); transparent area between M+CuA and mirror in shape of equilateral triangle, mirror about as long as high.

Caudal margin of male 10th tergite weakly emarginated. Male cercus almost straight when seen from above, its apex strongly bent downward, ending in sharp spine; inner, ventral part of cercus with short spine ( Figs. 10 E-F). Female cercus simple, elongately conical. Male subgenital plate about 1.3 times as long as wide, distinctly narrowed toward apex, apex with narrow, almost parallel sided incision, reaching past 1/3 of length of plate; styli short, about 1.8 times as long as wide ( Fig. 10 G). Female subgenital plate about 1.5 times as wide as long, apical part of plate narrowed and shallowly incised ( Fig. 10 D). Ovipositor shorter than hind femur, ratio tegmen/ hind femur 0.9, distinctly upcurved in its basal part ( Fig. 10 A).

Coloration.— General coloration green ( Fig. 36 C) (yellow in old museum specimens). Lateral carinae on the head, knees, and cubital veins of tegmina yellow with red edges; femoral spines often red; proximal end of middle tibia with dark brown, longitudinal spot; apex of ovipositor dark brown.

Measurements (mm). — Body (excl. tegmina): male 26, female 26-30; body (incl. tegmina): male 30, female 36- 40; pronotum: male 7, female 7.5-8; tegmen: male 19, female 25-28; hind femur: male 12, female 14.5-16, ovipositor 13-14.

Bioacoustics.— The call of A. colwelli consists of irregular series of short, buzzing trains, lasting 0.50- 1.28 s, separated by 233-262 ms long pauses (at 25°C). Each train consists of 34-89 individual wingstrokes ( Figs. 54 D-E). The call is low Q, without a clearly defined energy peak. It is likely, however, that most energy is allocated in ultrasonic frequencies, which I was unable to record due to the technical constraints of the recording equipment.

Distribution.— C. colwelli is so far known only from a handful of localities in northern and central Costa Rica ( Map 4 ).

Material examined.— COSTA RICA: Guanacaste Prov., Estación Pitilla, 9 km S Santa Cecilia, elev. 700 m, 15 September 1989 (coll. C. Moraga and P. Rios)—male (holotype) ( INBio); 3 km SE R. Naranjo, 16-31 January 1993 (coll. F.D. Parker)—male ( EMUS); Heredia Prov., Braulio Carillo N. P., Estac. El Ceibo, elev. 400-600 m, 15 September 1995 (coll. R. Aguilar and M. Zumbado)—female (allotype) ( INBio); Puerto Viejo, La Selva Biological Station, elev. 50 - 150 m, 10° 26' N, 84° 1' W, 15 August 1976 (coll. G.K. Morris)— female ( ANSP); same locality, 4 Oct. 1993 (coll. ALAS )—nymph; same locality and collector, CES 350, ex Dendropanax arboreus 12 Nov. 1994 -nymph; same locality and collector, CC 400 m, ex Pentaclethra macroloba 9 Oct. 1994—nymph; same locality and collector, CC 50 m, 14 Oct. 1994 —nymph; same locality and collector, CCC 400 m, ex Virola koschnyi 20 Oct. 1994; same locality and collector, CEN 550 m, 15 Nov. 1994 —nymph; same locality and collector, 7 Jan 1994 —nymph; same locality and collector, Sura 1100 m, 3 Nov. 1994 —nymph; same locality, 10 May 1998, coll. K.M. Smith and P. Naskrecki – 1 male ( INBio); Cartago Prov., Turrialba, 6 March 1965 (coll. S.S. and W.D. Duckworth)—female ( USNM); Turrialba, Agr. Sta., 10 February 1966 (coll. H.R. Roberts)—female ( ANSP).

Figures

FIG. 10. Acantheremus colwelli. A. female - habitus, B. female face, C. female head and pronotum, dorsal view, D. female subgenital plate, ventral view, E. male cerci, dorsal view, F. male left cercus, lateral view, G. male subgenital plate, ventral view.

FIG. 36. Costa Rican species of Conocephalinae s. l. A. Conocephalus angustifrons - male, B. Caulopsis cuspidata - female, C. Acantheremus colwelli - male, D. Vestria punctata - male and female, in copula, E. Copiphora hastata - male, F. Podacanthophorus vargasi - female, G. Copiphora rhinoceros - male eating a snail, H. Subria sylvestris - male, brown form.

FIG. 43. Stridulatory files of Costa Rican species of Conocephalinae s. l. A. Copiphora cochleata, B. Copiphora rhinoceros, C. ditto, enlarged fragment, D. Acantheremus colwelli, enlarged fragment, E. ditto, entire file, F. Metacaputus brenesi.

FIG. 54 Oscillograms of male airborne calls and substrate tremulations of Costa Rican species of Conocephalinae s. l. A. Lirometopum coronatum, airborne call, B. ditto, 0.5 s fragment, C. ditto, substrate tremulations and feet drumming, D. Acantheremus colwelli, E. ditto, 0.5 s fragment, F. Copiphora rhinoceros, G. ditto, 0.5 s fragment.

MAPS 1 - 6. Distribution of species of Conocephalinae s. l. in Costa Rica. 1. Conocephalus angustifrons, C. cinereus, 2. Conocephalus saltator, C. ictus, 3. Conocephalus magdalenae, Orchelimum fraternum, Lipotactomimus rowelli, 4. Lirometopum coronatum, Acantheremus colwelli, 5. Copiphora rhinoceros, C. cochleata, C. brevicauda costaricensis, 6. Copiphora hastata, C. cultricornis, C. ottei.