Ligypterus najtae, Vicente & Robillard, 2017

Vicente, Natállia & Robillard, Tony, 2017, Ligypterus najtae n. sp. from Mounts Tumuc-Humac in French Guiana (Orthoptera, Grylloidea, Gryllidae, Eneopterinae), Zoosystema 39 (1), pp. 125-136 : 127-130

Ligypterus najtae n. sp.

( Figs 1-8 )

TYPE MATERIAL. — Holotype. ♂. Guyane. Monts Tumuc-Humac , Massif du Mitaraka, 2.235494N, 54.44768O (C100), 350 m / 2.233664N, 54.4419O (C1000), 415 m, Planète revisitée Guyane 2015, 23.II- 10.III.2015, nuit, sur plante, mort en élevage, enregistrement appel-F0-male2, F. Legendre & S. Hugel (MNHN-EO- ENSIF4165).

Allotype. ♀. Same informations as holotype (MNHN-EO-EN- SIF4166).

Paratypes. 7 ♂, 1 ♀. Guyane. Monts Tumuc-Humac, Massif du Mitaraka, 2.235494N, 54.44768O (C100), 350 m / 2.233664N, 54.4419O (C1000), 415 m, Planète revisitée Guyane 2015, 23.II- 10.III.2015, nuit, sur plante, F. Legendre & S. Hugel: 1 ♂ (FL193), échantillon moléculaire E46, (MNHN-EO-ENSIF4169) ; 3 ♂, 1 ♀ (FL208, FL211, FL290, FL210) (MNHN-EO-ENSIF4170- ENSIF4173); 1 ♂, mort en élevage, enregistrement appel-FO-male1 (MNHN-EO-ENSIF4167); 1 ♂ (SH190), h = 50 cm, échantillons moléculaires LDG525/559 (MNHN-EO-ENSIF1706).

ADDITIONAL MATERIAL EXAMINED. — Guyane. Same informations as paratypes, two juveniles (FL 207, FL291) (MNHN).

TYPE LOCALITY. — French Guiana, Mounts Tumuc-Humac, 2.233664N, 54.4419W, 415 m.

ETYMOLOGY. — The species is dedicated to Judith Najt, who kindly welcomed TR in her research team when she was at the head of the ESA8043 CNRS (former name of current ISYEB-UMR7205). As team leader, Judith was always able to provide support, advice and coffee to students knocking at her door. Since TR’s master project was dealing with Neotropical eneopterines (Robillard & Desutter- Grandcolas 2005), it was natural to dedicate this new Ligypterus species to Judith.

DIAGNOSIS. — Species close to L. fuscus Chopard, 1920 , from which it differs by male genitalia: pseudepiphallus wider, lophi widened laterally and more separate from each other, pseudepiphallic parameres separated by their width (almost touching each other in L. fuscus ); and by shape of female copulatory papilla: rounded apex folded ventrally (straight and not rounded in L. fuscus ).

DESCRIPTION

Size rather large for the genus, typical stocky shape. Coloration contrasted yellow to orange brown, mottled with dark brown ( Fig. 1 ). Head dorsum yellow with six dark brown longitudinal bands ( Fig. 2B ), the two widest behind antennae forming one anterior punctuation, the two median bands punctuated along their whole length ( Fig. 2B ). Fastigium dark brown, yellow apically, with a black area posterior to median ocellus. Ocelli yellow. Eyes dark brown, with a wide longitudinal light band in dorso-lateral region. Scapes yellow with brown stains. Face mostly yellow with variable dark brown patterns ( Fig. 2A ), including area below the antennae extended dorsally below median ocellus, two dark stains on clypeus forming a circular pattern and central area of labrum; lateral part of head yellow or whitish with dark spots ( Fig. 2C ). Mandibles yellow with dark patterns; maxillary palpi mostly dark brown with yellow areas, their fifth article dark brown with a yellowish ring. Pronotum ( Fig. 1 ): dorsal disk rectangular, wider than long, densely setose with two marks near anterior margin; coloration orange brown mottled with dark and light spots, lateral margins yellow; posterior margin straight, mostly light colored, with variable dark stains; lateral lobe with a black band underlying dorso-lateral margin, progressively lighter ventrally; ventral margin concave in median region. Legs: FI-II yellow with black spots, TI-II yellow with dark rings. Trochanter yellow. FIII yellow mottled with whitish and black spots, with strong striated dark brown patterns on outer faces; knees dark brown; TIII dark brown with faint yellowish spots. Abdomen dark brown. Cerci mostly yellow brown with dark spots.

Male

FW ( Fig. 3A ) reaching beyond abdomen mid-length, mostly translucent brown with dark brown area anterior to 1A, and pale areas including CuA vein and anal node area, other veins dark brown. FW venation typical of genus: 1A slightly bisinuated near angle, with 116 stridulatory teeth, nine on basal angle and 107 on transverse part of file. Harp longer than wide, with one strong V-shaped oblique vein. Mirror (d1) wider than long, crossed by an accessory vein in posterior quarter and extended posteriorly by widened d2, d1+d2 forming a wide ellipsoid area. Cell c1 narrow. Lateral field mostly brown, area between M and R vein dark brown to black; Sc with seven (n=4) bisinuated branches and three more ventral veins.

Male genitalia

Pseudepiphallus triangular ( Fig. 4 ), less widened laterally than in L. fuscus , with shorter triangular posterior lophi, widened basally and more separated than in L. fuscus ; in lateral view ( Fig. 5 ), lophi clearly sclerotized dorsally, membranous ventrally with a wide basal membranous lobe. Rami straight, shorter than rest of pseudepiphallus. Pseudepiphallic parameres widely separated, very sclerotized, with one lobe oriented dorsally and two ventral lobes finely denticulate; posterior lobe elongate, anterior one rounded with membranous basis. Ectophallic fold with two J-shaped lateral sclerites. Endophallic sclerite large, with two strong postero-lateral arms and a median triangular expansion; endophallic apodeme made of a median crest shorter than in L. fuscus .

Female

FWs shorter than in males ( Figs 1 ; 3B ; 7A, B ), slightly overlapping, dark brown with orange veins; venation with five main longitudinal veins and strong transverse ones barely distinguishable the ones from the others, forming a dense network of veins. Lateral field with area between M and R dark as in males.

Female genitalia

Copulatory papilla close to that of L. heydeni ; circular basal ring with a short posterior expansion; apex rounded, smaller than in L. heydeni , folded ventrally.

Juvenile

First instars dark brown with whitish spot on head ( Fig. 7C ); later instars more similar to adults in coloration.

Measurements

See Table 1.

Habitat and life history traits

Ligypterus najtae n. sp. was found on low vegetation in/near the leaf litter in forested areas, from where males sing during night time ( Fig. 7A, B ).

A

Calling song

The calling song of L. najtae n. sp. ( Fig. 8 ) was recorded in the laboratory ( Table 2). At 25°C (FO-male2), the song echeme is made of 20-25 syllables (m =22.3 ±1.4) and lasts for 300± 25 ms, for an echeme period of 2.44 ± 0.34 s (duty cycle = 12.2%). Most echemes show an irregular beginning comprising 2-3 syllables (m =2.1±0.3, n=12), separated by a pause of 54 ±10 ms from a more regular trill comprising 18- 23 syllables (trill duration = 215± 31 ms). Syllables are short (duration= 8.8± 0.1 ms; period=11.5 ±3.4 ms) and show a slightly indented amplitude profile. The spectrum shows a clear dominant peak at 18.54±0.29 kHz corresponding to the third harmonic of a lower fundamental frequency (c. 6.2 kHz). Compared to that of L. fuscus ( Robillard et al. 2015; table 2), the song of L. najtae n. sp. has a similar echeme structure, but shows a longer irregular beginning and a slightly lower dominant frequency (19.73 kHz in L.fuscus ). Syllables have a similar duration in both species, with a shorter syllable period in L. najtae n. sp. Song files of two recorded specimens (MNHN-EO-ENSIF4165 and MNHN-EO-ENSIF4167) have been deposited in the MNHN Sound Library with the following inventory numbers, MNHN-SO-2017-32 and MNHN-SO-2017-33 respectively.

Figures

FIG. 1. — Ligypterus najtae n. sp.: A, B, male holotype in dorsal (A) and lateral (B) views; C, D, female allotype in dorsal (C) and lateral (D) views. Scale bar: 1 cm.

FIG. 2. — Ligypterus najtae n. sp.: head in facial (A), dorsal (B) and lateral (C) views. Scale bar: 1 mm.

FIG. 3. — Ligypterus najtae n. sp.: A, male forewing venation; B, female forewing venation. Scale bars: 1 mm.

FIG. 4. — A, B, Ligypterus najtae n. sp.: male genitalia in dorsal (A) and ventral (B) views; C, D, Ligypterus fuscus Chopard, 1920: male genitalia in dorsal (C) and ventral (D) views. The red arrows indicate the windened part of pseudepiphallic lophi. Scale bar: 1 mm.

FIG. 5. — A, Ligypterus najtae n. sp., apex of male genitalia in lateral view; B, Ligypterus fuscus Chopard, 1920, apex of male genitalia in lateral view. Scale bar: 0.5 mm.

FIG. 6. — Ligypterus najtae n. sp., female copulatory papilla in ventral (A), dorsal (B), and lateral views (C). Scale bar: 0.5 mm.

FIG. 7. — Ligypterus najtae n. sp.: A, female on low vegetation; B, male in leaf litter; C, juvenile (second instar). Photographs: S. Hugel (A); T. Robillard (B, C).

FIG. 8. — Calling song of Ligypterus najtae n. sp.: A, oscillogram of five echemes; B, C, oscillogram (B) and sonogram (C) of one echeme; D, E, detailed oscillogram (D) and frequency spectrum (E) of one syllable. Arrows on spectrum indicate the harmonic series (f1, f2, f3) derived from fundamental frequency f1.