Cardiodactylus admirabilis, Tan & Robillard

Tan, Ming Kai & Robillard, Tony, 2014, A new species of Cardiodactylus (Orthoptera: Grylloidea: Eneopterinae) from Singapore, Zootaxa 3764 (3), pp. 364-376 : 365-371

Cardiodactylus admirabilis, Tan & Robillard , n. sp.

( Figs. 1 A, 2–7)

Cardiodactylus singapura Robillard, 2011 —Tan et al. 2012: 66 (juvenile specimens wrongly identified).

Material examined. Holotype (male): Singapore, Admiralty Park (Nature Park), secondary forest near mangroves, N01.44639, E103.77930, 11.2 ± 5.4 m, on Dillenia leaf, 25 June 2013, 2017 hours, coll. H. Yeo & M. K. Tan ( ZRC.ORT.1020).

Paratypes. Singapore, same locality as holotype, secondary forest near mangroves, 3 males, coll. H. Yeo & M. K. Tan: (1) N01.44637, E103.77926, 27.4 ± 5.6 m, on Dillenia leaf, 15 June 2013, 2120 hours, collected as the final instar, moulted into adult on 16 June 2013 ( ZRC.ORT.1021); (2) N01.44676, E103.77919, 10.7 ± 5.2 m, among herbs, 25 June 2013, 2042 hours ( ZRC.ORT.1022); (3) N01.44682, E103.77908, 17.2 ± 6.4 m, calling on leaf of tree sapling, calling song recorded in-situ, 6 July 2013, 2145 hours (MNHN-EO-ENSIF3441).

Diagnosis. Species of average size for the species group, characterised by contrasted coloration dark brown and yellow, with a wide rounded yellow area posterior and male genitalia more or less triangular, with a little rounded posterior apex. Very close to Cardiodactylus thailandia Robillard, 2011 from which it differs the following characters: general colouration brown and whitish while C. thailandia is almost black and vivid yellow; male FW: diagonal not bicolour; fore and middle legs: pale yellow brown with dark brown patterns (spots on femur, rings on tibiae) while legs of C. thailandia are almost entirely orange brown; male genitalia differ by pseudephiphallus posterior region (posterior lobe wider than in C. thailandia ) and dorsal edge of dorsal ridges with different shape.

C. admirabilis differs strikingly from Cardiodactylus singapura Robillard, 2011 by its colouration more contrasted on FW dorsal field, with a wide whitish area posterior to mirror ( Fig. 1 ); and male genitalia: rami wide (narrow in C. singapura ), with preapical plate more sclerotised along edge (equally sclerotised in C. singapura ); ectophallic arc angulated (more broadly rounded in C. singapura ); ectophallic apodemes lamellate (thin in C. singapura ); endophallic sclerite sclerotized and rather wide, not tapering anteriorly but truncated with the apex acute (small and tapering anteriorly to an acute apex in C. singapura ). Contrary to most species of the species group described from this geographic area ( Robillard, 2011; Robillard et al. in prep), C. admirabilis shows a multisyllabic calling song and not a monosyllabic song.

Description. Size average for the species group. General colouration contrasted, light brown with dark brown patterns ( Fig. 2 ). Head dorsum yellow brown with 4 wide dark brown bands, more or less punctuated, bordered by dark brown triangles posterior to eyes and a yellow line more externally (Fig. 3A). Fastigium yellow laterally, median area dark brown, joint with the 2 outermost dark brown bands on vertex. Scapus light brown. Antennae heterogeneously brown. Face yellowish to light brown, diversely mottled with brown, with 2 parallel lines on the fastigium (Fig. 3B). Maxillary palpi yellowish. Head laterally sometimes with a dark brown area posterior to eyes and genae bordering the eyes, progressively lighter ventrally (Fig. 3C). Pronotum: Dorsal disk trapezoidal, anterior margin concave, posterior margin straight or slightly bisinuated; dark brown mottled with light brown or yellow spots. Lateral lobes dark brown, with a black longitudinal band on dorsal half, ventral edges and dorsal margins yellow (Fig. 3C). Legs light brown to yellow brown, knees dark brown, femora mottled with dark brown; tibiae darker, more or less banded; tarsomeres with dark brown ends ( Fig. 2 ). Tarsomeres III-1 with 3 spines on dorsoexternal edges (m=3, n=4). Hind wings longer than FWs, the dark brown tail exceeding the forewings less than twice longer than the pronotum ( Fig. 2 A). Cerci light brown with faint black rings. Tergites dark brown or black; sternites light brown to brown. Subgenital plate yellow brown.

Male. FW as shown in Fig. 3D. Colouration: Dorsal field cells dark brown, veins mostly orange brown, some areas white with yellow veins, including base of FWs and anal veins, area near plectrum, part of the chords, and wide semi-circular area posterior to mirror. Base of chords with a dark brown sclerotization. Harp posterior angle and anterior area with a white and yellow sclerotized area. Lateral field with cells mostly dark brown, except areas near projections of Sc; veins M, R, Sc dark brown, transverse veins and projections of Sc pale yellow. FW venation: 1A slightly bisinuated; stridulatory vein with transverse part 3.3 mm, with 176 teeth on the transverse area of the file, 18 on the curved area, and 22 near base of 1A (n=1, holotype) (Fig. 3E). CuP absent. Harp longer than wide, with 2 w-shaped harp veins; posterior margin raised along diagonal vein. Mirror area variable, c1 very long and very narrow and fairly straight to slightly sinuous, c2 quite large; mirror (d1) longer than wide, not rounded, generally separated in four parts by transverse and oblique veins, separating vein more posterior than anterior, the posterior part triangular; e1 cell very elongated, along the mirror. Apical field long and triangular; with 3 wide cell alignments posterior to mirror, 2 apical most wide cells with dividing veins. Lateral field: Sc with 7–8 projections and 3 more ventral veins (m=7.8, 3, n=4).

Male genitalia as shown in Fig. 4 : Pseudepiphallus very sclerotized and little setose, more or less triangular, only slightly narrowed new mid-length. Dorsal ridges divergent posteriorly, their dorsal edge bean-like, slightly asymmetrical, carinated interiorly, the left one curved, the right one straight; pseudepiphallus bisinuated laterally. Pseudepiphallic sclerite with latero-anterior triangular expansions; the membrane between them with short strong setae. Apex of pseudepiphallus spoon-like, not rounded. Rami wide, with wide triangular preapical plate; plate with lateral edge rounded and more sclerotised; with apex lamellate and acute. Pseudepiphallic parameres trilobate, the posterior lobe wide. Ectophallic arc complete, with a short posterior expansion. Ectophallic apodemes lamellate, diverging, their apex curved dorso-interiorly. Apex of ectophallic fold trilobate, membranous. Base of ectophallic apodemes with thin sclerotized expansions oriented posteriorly. Endophallic sclerite small, with a medio posterior anpansion and 2 thin lateral arms sclerotised. Endophallic apodeme with both lateral lamellas, and a short medio-dorsal crest. Membrane of endophallic cavity smooth.

Female. Unknown.

Juvenile ( Fig. 5 ). Early instars generally pale with irregular spots of different size; dorsum of head mostly dark brown with faint yellow bands; with black longitudinal bands from genae towards abdominal apex ( Fig. 5 A, B). Later instars with more contrasted colouration, body darker with spots denser; dorsum of head with more contrasted yellow bands ( Fig. 5 C).

Measurements. See Table 1 .

Males (n = 4) 3.1–3.9 4.6–4.9 14.9–16.3 4.5–4.7 5.0–5.5 15.8–15.9 - 13.6–14.6 (3.5) (4.8) (15.4) (4.6) (5.1) (15.9) (14.1) TIIIs TaIIIs Ias Ibs Oas Obs

Holotype 9 2 13 2–3 5

Males (n = 4) 8–10 (8.8) 2 (2) 10–13 (12) - 3–5 (3.8)

* Hind femur shrunk upon preservation.

Etymology. The name reflects the surprise to discover a new species from the non-reserve parkland in a highly urbanised Singapore. The name also coincide with part of the name the type locality, Admiralty Park; from Latin, admirabilis = surprising.

Distribution. This species is so far known from Admiralty Park in the north of Singapore and not found in central areas (Bukit Timah Nature Reserve and Central Catchment Nature Reserve) in which Cardiodactylus singapura exists. Conversely, Cardiodactylus singapura was not sighted and recorded from Admiralty Park.

FIGURE 3. Cardiodactylus admirabilis n. sp. male: head in dorsal (A) and anterior (B) views; head and pronotum in lateral view (C); FW in dorsal view (D); stridulatory file (E). Scale bar: A–D, 1 mm; E, 0.5 mm.

Habit and life history traits. Cardiodactylus admirabilis n. sp. is a nocturnal species, although the nymphs are sometimes sighted in the day. In captivity, the adults were fed with Dillenia fruits, flowers and leaves in which the species may be found.

Behaviour. Calling song ( Figs. 6 , 7 ): The calling song of Cardiodactylus admirabilis n. sp. is a short echeme made of a triplet of syllables emitted by groups of 3 or 4, unlike the other Cardiodactylus species described from the region, including C. singapura , which have mono-syllabic calling songs ( Robillard, 2011; Robillard et al. in prep). The calling song has the following features: echeme duration = 205.6±7 ms, echeme period = 2.11±1.3 s, echeme duty cycle = 11.7±4.4 %; syllable duration = 36.9±3.9 ms, syllable period = 84.8±0.8 ms, syllable duty cycle = 43.5 %; dominant frequency (3rd peak of the spectrum) = 14.26 0.74 kHz. The syllables within the echeme tend to be slightly different, as shown in Table 2 : the frequency increases by more than 1.5 kHz between syllable 1 an d syllable 3; syllable 2 tend to be longer then the others, and syllables 1 and 2 include gaps, while syllable 3 is continuous and more intense.

Discussion. The nymphs of this species were previously sighted in Admiralty Park and wrongly recorded in Tan et al. (2012) as Cardiodactylus singapura .

Figures

FIGURE 1. Cardiodactylus adults recorded in Singapore: Cardiodactylus admirabilis n. sp. (A) and Cardiodactylus singapura Robillard, 2011 (B) in dorsal view.

FIGURE 2. Cardiodactylus admirabilis n. sp. male habitus: dorsal (A) and lateral (B) views. Scale bars: 2 mm (A); 10 mm (B).

FIGURE 4. Cardiodactylus admirabilis n. sp. male genitalia: dorsal (A); ventral (B) and lateral (C) views. Scale bar: 1 mm.

FIGURE 5. Cardiodactylus admirabilis n. sp. juvenile habitus: lateral (A) and dorsal (B) views of early instar and dorsal view of later instar (C).

FIGURE 6. Cardiodactylus admirabilis n. sp. calling song: oscillogram of four echemes (A); sonogram of four echemes (B); oscillogram of one echeme (C). Symbols: f 1, f 2, f 3 correspond to the first, second and third harmonic frequencies in the spectrum.

FIGURE 7. Cardiodactylus admirabilis n. sp. calling song: oscillograms (A, C, E) and power spectrum (B, D, F) of syllable 1 (A, B), syllable 2 (C, D) and syllable 3 (E, F). Symbols: f 1, f 2, f 3 correspond to the first, second and third harmonic frequencies in the spectrum.

Tables

TABLE 1. Measurements of Cardiodactylus admirabilis n. sp. (in mm, mean values in brackets).

PronL	PronW	FWL	FWW	HWT	FIIIL	FIIIW	TIIIL
Holotype 3.9	4.8	15.2	4.6	5.0	15.9	4.1	13.6
Male paratype 3.6 (15 Jun.2013)	4.8	14.9	4.5	5.0	15.8	3.5*	14.6
Male paratype 3.5 (25 Jun.2013)	4.6	15.0	4.5	5.0	15.9	4.2	14.4
Male paratype 3.1 (6 Jul.2013)	4.9	16.3	4.7	5.5	15.8	4.3	13.9