Trigonidium solis Tan & Baroga-Barbecho & Yap 2019, sp. nov.
Creators: name: Tan, Ming Kai
name: Baroga-Barbecho, Jessica B.
name: Yap, Sheryl A.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Trigonidiidae
Trigonidium
Trigonidium solis

description: Trigonidium solis sp. nov.
(Figs. 3–7)
Material examined. Holotype (male, Siargao18_36): Philippines, Surigao del Norte, Siargao Island, Maayahay, Del Carmen, N9.86107 E126.03321, 56.1± 6.8 m.a.s.l., 9 April 2018, 0 0 0 6 hours, coll. M.K. Tan, H. Yeo, J.B. Baroga-Barbecho, S.A. Yap (UPLBMNH).
Paratypes (2 males and 2 females): Philippines, same locality as holotype, coll. M.K. Tan, H. Yeo, J.B. Baroga-Barbecho, S.A. Yap: 1 female (Siargao18_33), N9.86077 E126.03311, 61.4± 5.7 m.a.s.l., 8 April 2018, 2357 hours (UPLBMNH); 1 female (Siargao 18_61), same locality as holotype, Barangay Esperanza, Del Carmen, N9.86804 E126.02708, 65.2± 7.2 m.a.s.l., 16 October 2018, 0 830 hours, coll. M.K. Tan & J. B. Baroga-Barbecho; 1 male (Siargao 18_64), same locality as holotype, Barangay Esperanza, Del Carmen, N9.86968 E126.02913, 82.1± 5.9 m.a.s.l, 16 October 2018, 1152 hours, coll. M.K. Tan & J. B. Baroga-Barbecho; 1 male (Siargao 18_70), same locality as holotype, Maayahay, Del Carmen, N9.86092 E126.03316, 56.6±6.0 m.a.s.l, 16 October 2018, 1949 hours, coll. M.K. Tan & J. B. Baroga-Barbecho (all ZRC).
Generic status. We propose that our species belongs to Trigonidium s. l. based on the distal epiphallic lobes are rather simple, short and immovable in relation to the rest of epiphallic part; and their ectoparameres, rachis (with apical spine-like lobule [virga]) and formula and very similar in the shape to congeners.
The species shares some resembles with species from Rhicnogryllus by habitus, tegmen not pubescent and abdomen distinctly humped dorsally but differs by the longitudinal veins not crenulated (= elevated), male genitalia with apical spine-like lobule (virga) (vs. without such lobule). This species also resembles species from Metioche but differs by the absence of metanotal gland, tegmen rounded in lateral view (instead of flat), and general morphology of genitalia.
Subgeneric status. We propose that our species belongs Trigonidium s. str. (sensu Gorochov, 1987) based on tympana on fore tibia absent; tegmen rounded in lateral view, not pubescent and without stridulatory apparatus; metanotal gland in males absent; and male genitalia of our species resembles that of the type species T. (Trigonidium) cicindeloides.
Diagnosis. The new species differs from congeners by yellow colouration and black spot on tegmen; and male genitalia with posterior apex of pseudepiphallus forming thin, sclerotized lophi with margins smooth (without setae and spines) and obtuse apex.
Comparison with congeners. Whenever possible, we compared the new species with congeners using male genitalia. Otherwise (or when genitalia information is not available), colour may be useful since we did not observe distinct intra-specific colour variations among the new species and among some of the examined congeners.
From Australian Trigonidium s. str., the new species shares the yellow to orange head and pronotum (without black colouration) with T. amarina, T. bundilla, T. canara, T. goobita, T. killawarra, T. meekappa, T. parinervis; but differs from T. canara by tergites not black, from T. killawarra by tegmen without two pale lateral stripes, and from T. parinervis by tegmen not black. The new species is similar to T. amarina, T. bundilla, T. goobita, T. meekappa by also mostly yellow tegmen; but all the above species from Australia differs by lophus of posterior apex of pseudepiphallus with apex obtuse (instead of acute) and without setae or spines and posterior margin of pseudepiphallic parameres [=ectoparameres] with small lobule and without setae or spines.
From Southeast Asian Trigonidium s. str., the new species differs from T. novarae from Java by tegmen dorsal field not “coarsely streaked” with elevated longitudinal veins; from T. rubellonigrum from Vietnam by female tegmen not completely black and longitudinal veins not elevated.
The new species also differs from other remaining black Trigonidium s. str. (i.e., T. inopinum from Fiji Islands; T. australiana, T. canberrae, T. infuscata and T. lalwinya from Australia; T. cicindeloides; T. erythrocephalum from South Africa; T. nigritum from Madagascar; T. humbertianum from Sri Lanka) by its yellow colouration (instead of black or dark brown).
We rule out that our species is another yellow Trigonidium s. l., specifically Trigonidium (Parametioche) rectinervis (Chopard, 1951) (see comments in Part I), as it differs by tegmen with the longitudinal veins not crenulated (= elevated) and by colouration.
Description. General appearance typical of type species T. cicindeloides: tympana on fore tibia absent, tegmen in lateral view rounded and not pubescent, metanotal glands in males absent. Male and female live habitus as in Fig. 3; male dorsal and lateral habitus as in Fig. 4; female dorsal habitus as in Fig. 7A. Head, together with eyes, clearly wider than pronotum (Fig. 4). Frontal rostrum flattened, wider than scapus (Fig. 5A); with a few long setae (Fig. 4A). Vertex flattened dorsally (Figs. 4B, 5A). Antennal segments, including scapus, pubescent. Eyes very large, protruding laterally, from dorsal view slightly elongated (Fig. 4A); in lateral view slightly hemispheric (Fig. 4B). Genae swollen, not pubescent (Fig. 4B). Maxillary palpi elongated; last three segments of about equal length (apical and third segments slightly longer than second segment); apical segment triangular, longer than wide, with apex truncated. Labial palpi with apical segment long and slightly swollen at the apex. Pronotum wider than long; with a few long setae but more pubescent along margins (Fig. 3); sulci indistinct (when alive [Fig. 3]); anterior and posterior margins straight; dorsal disc flattened (Fig. 4A). Lateral lobes of pronotum longer than high, ventral margin sinuous, anterior and posterior angles obtuse (Fig. 4B). Metanotal gland absent (Fig. 5B). Tegmina same in males and females, in lateral view appears rounded (Figs. 4, 7A), not pubescent; reaching abdominal apex, but not covering epiproct; with longitudinal veins not elevated; without stridulatory apparatus in males. Hind wing absent (Fig. 5B). Legs generally pubescent and with long setae. Tarsal middle segments with prominent adhesive pads. Hind tibiae with three inner and three outer subapical spurs; two inner and two to three outer apical spurs, inner ones distinctly longer than outer ones.
Male: Anal plate tongue-shaped and elongated, longer than wide; basal half (tenth abdominal apex) tapers posteriorly; apical half (epiproct) with lateral margin straight and apex broadly rounded (Fig. 5C). Subgenital plate broader at the base than long, with apex wide-roundly excised and a lobe in the middle (Fig. 5D). Cerci simple, tapering and long surpassing hind femora. Male genitalia as in Fig. 6. Pseudepiphallus [= epiphallus] separated into two lateral parts joined by an anterior sclerotized bridge situated somewhere along the middle of the length of rami; sclerotized bridge curved. Posterior edges of pseudepiphallic sclerite with a stout lobule in the middle (ps lb). Posterior apex of pseudepiphallus forming thin, sclerotized lophi (ps lo); lophus feebly curved inwards, with margins smooth (without setae and spines), with apex obtuse, narrowly emarginated (indented) at the inner margin at the base (ps ind). Pseudepiphallic parameres (ps p) [=ectoparameres] transverse, with posterior margin with a small and stout lobule in the middle (ps p lb). Ectophallic fold [= rachis] (ra) large forming a broad sclerotized virga (v) with somewhat acute apex. Ectophallic apodeme (ec ap) [= endoparamere apodeme] weakly sclerotized, appearing flat and broad. Ramus (r) slender, reaching anterior of ectophallic apodeme. Endophallic sclerite (en s) [= formula] elongated along dorsal cavity, with a median crest (en ap c), with lamella of apodemes (en ap l) appearing flat and broad.
Female (Fig. 7): Habitus similar to males (Fig. 3). Supra-anal plate with apex emarginated in the middle. Subgenital plate broader than wide, with anterior margin straight, curved and tapering into an emarginated apex (Fig. 7C). Ovipositor not surpassing cerci; basal third with margins smooth, curved feebly; apical third with dorsal margin distinctly denticulated, ventral margin also denticulated but less dense and only towards the apex (Fig. 7D). Ventral valves longer than dorsal valves (Fig. 7D).
Colouration: Males and females similarly coloured, generally yellow (Fig. 3). In fresh specimens, head (including scapus) yellow, with setae on dorsum brown. First antennal segment yellow brown, subsequently becoming black (Fig. 3). Face pale yellow, without any markings (Fig. 5A). Palpi with segments light yellow, sometimes slightly dark at anterior and posterior margins. Pronotum yellow, with brown setae, with posterior margin brown. Tegmina nearly transparent, shiny yellow, with apical area on both dorsal and lateral field black (Fig. 3, 4). Thoracic sternites pale yellow. Abdominal tergites and sternites pale yellow; apex with a tint of green, cerci with pale green basally, dark apically. In female, dorsum of tergites at the apical half black, extending more towards the apical segments (Figs. 3C, 3D, 7A). In males, posterior margin of tenth abdominal tergite black or brown (Fig. 5C), subgenital plate with a large black squarish spot in the middle (Fig. 5D). Legs yellow, without patterns, knees and tibiae generally darker. Inner surface of hind femora with a relatively large black spot at the basal third. Hind tibiae with spurs dark. Middle and apical segments of hind tarsi black. Ovipositor pale basally, red brown thereafter (Fig. 7D).
Measurements. See Table 2.
Etymology. The species name refers to the resemblance of the cricket to the Sun (= solis, in Latin) owing to the rounded body and yellow colouration.
Remarks. This new species represents the first species of the genus described from the Philippines. However, it is likely an artefact of poor sampling effort in this region and cryptic nature of these small crickets. We can expect more species to be discovered with more concerted sampling effort in Southeast Asia.
description: Published as part of Tan, Ming Kai, Baroga-Barbecho, Jessica B. & Yap, Sheryl A., 2019, Taxonomic notes on Trigonidium and related groups with one new species from the Philippines (Orthoptera: Trigonidiidae; Trigonidiinae), pp. 573-587 in Zootaxa 4564 (2) on pages 580-586, DOI: 10.11646/zootaxa.4564.2.13, http://zenodo.org/record/2589058