A new species of the genus Xistra Bolívar, 1887 (Orthoptera, Tetrigidae) from Negros Island, the Philippines

Romeo R. Patano Jr.^*1,2 | Josip Skejo ³ | Victor B. Amoroso ^1,4 | Fulgent P. Coritico ^1,4 | Niko Kasalo ⁵

1 Center for Biodiversity Research and Extension in Mindanao; 2 Animal Biology Division, Institute of Biological Sciences, College of Arts and Sciences, Central Mindanao University, Musuan, Maramag, Bukidnon 8710, Philippines.

3 Evolution Laboratory, Division of Zoology, Department of Biology, Faculty of Science, University of Zagreb Horvatovac 102a, HR-10000 Zagreb, Croatia.

4 Plant Biology Division, Institute of Biological Sciences, College of Arts and Sciences, Central Mindanao University, Musuan, Maramag, Bukidnon 8710, Philippines.

5 Laboratory of Evolutionary Genetics, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia.

ABSTRACT. A new species of genus Xistra Bolívar, 1887, subgenus Xistra, from Negros Island, Visayas (the Philippines) is described here—Xistra balinsasayaoensis sp. nov. (Balinsasayao’s horned pygmy grasshopper). It was first documented in May 2017 by an amateur photographer and was finally collected in October 2023. The species belongs to the subgenus Xistra due to its smooth pronotum with a low median carina and moderately high horns. There are now a total of six species of Xistra, three of which are members of the subgenus Xistra. The photographic records of living specimens and their microhabitats, including their bryophyte associates, are provided as well.

KEYWORDS: Balinsasayao Twin Lakes, Natural Park, Montane forest, New species, Oriental, Taxonomy

Citation: Patano Jr., R.R., Skejo, J., Amoroso, V.B., Coritico, F.P., Kasalo, N. (2026) A new species of the genus Xistra Bolívar, 1877 (Orthoptera, Tetrigidae) from Negros Island, the Philippines. Journal of Insect Biodiversity and Systematics, 12 (01), 67–79.

INTRODUCTION

The family Tetrigidae (Orthoptera), commonly known as pygmy grasshoppers, has more than 2,000 described species worldwide (Cigliano et al. 2025). More than 40 genera and 120 species are currently recorded from the Philippines (Tan et al. 2025), but the number is still growing (Skejo et al. 2025). Tetrigidae is still a problematic taxon that needs a comprehensive taxonomic revision (Skejo et al. 2025). Some Philippine pygmy grasshopper genera and species were revised recently, including the genus Xistra Bolívar, 1887 (Skejo et al. 2025), to which the new species described herein belongs. The genus Xistra was described by Bolívar (1887) based on facial and pronotal characters, with nine distinct species. These species were recently placed in different genera, with only the type species, Xistra gogorzae Bolívar, 1887, remaining in its original taxonomic placement (Cigliano et al. 2025, Skejo et al. 2025). The most recent revision of Xistra (Skejo et al. 2025) proposed two subgenera — Xistra (Xistra) Bolívar, 1887, and Xistra (Tegoxistra) Skejo, Patano, Škorput & Kasalo, 2025. The former includes X. gogorzae, X. sagittaria Bolívar, 1887, and the herein described species, while the latter includes Xistra derijei Patano, Mohagan, Tumbrinck, Amoroso & Skejo, 2021, X. cristifera Günther, 1935, and X. corniculata (Stål, 1877). Two interesting undescribed species of Xistra from Mindanao (white coloration) and Negros Island (green coloration) have been known from photographs but have not been collected, as reported by Patano et al. (2021). Fortunately, the latter was collected in our recent faunistic survey in a forested area of Negros Island in Balinsasayao Twin Lakes Natural Park (a Long-Term Ecological Research (LTER) site), the same locality where the species was photographed in 2017 by Veronica Prudente. Here, we describe this new species and provide live photographs of male and female specimens in their natural habitat. In addition, we also describe its natural habitat, including its bryophyte associates.                                       

MATERIAL AND METHODS

An approved Wildlife Gratuitous Permit was issued by the Department of Environment and Natural Resources (DENR) in compliance with RA 9147. A fieldwork was then carried out in the study site (Balinsasayao Twin Lakes Natural Park, Negros Island) with the support of the people’s organization and the local government unit of Sibulan, Negros Oriental. Male and female specimens of the new species were collected in established transects and hectare plots in Balinsasayao Twin Lakes Natural Park (BTLNP), Negros Island, through opportunistic sampling, and handpicking during the diurnal period (08:00 h – 14:00 h), 26–28.x.2023, at the following coordinates and elevation: 09°21'35.16"N, 123°10'53.52"E; 897–910 m a.s.l. The site is a declared Long-term Ecological Research (LTER) site of the Philippines (Fig. 1). The hind legs of the new species were stored separately in a vial filled with absolute ethyl alcohol for future molecular study. Macro photographs of the new species were taken using the Olympus TG6 digital camera. Before the collection of the new species, it was first photographed in its natural habitat. Male and female specimens of the new species were then mounted, measured, and photographed. Final images of the species were then produced using licensed Adobe Photoshop CS software version 22. Specimens of the new species were identified by comparing them with type specimens of other species, through the available photographs of Xistra uploaded to the Orthoptera Species File (Cigliano et al. 2025) or examination of museum specimens. The holotype of Xistra balinsasayaoensis sp. n. was initially deposited in the Central Mindanao University (CMU), University Museum, Zoological Section, and will be deposited finally at the National Museum of the Philippines. The description of the new species was based on the morphological terminology of Hancock (1913), Tumbrinck (2014), and Muhammad et al. (2018). Morphological sets of characters important for the taxonomy and identification of species (as presented by Patano et al. (2021) and Skejo et al. (2025) currently belonging to the genus Xistra are (i) shape and height of fastigial horns, (ii) position of the bifurcation of the frontal costa and of the lateral ocelli, (iii) presence, arrangement, and height of the pronotal projections, and (iv) shape of fore, mid, and hind femora. Specimens were measured and then compared to available measurements of known and related Xistra species as presented by Patano et al. (2021). Measurements are given in accordance with Tumbrinck (2014). The measurements that were taken are the following: Body length (BL), pronotum length (PL), pronotum lobe width (PLW), pronotum height (PH), fore femur length (FFL), fore femur width (FFW), mid femur length (MFL), mid femur width (MFW), hind femur length (HFL), hind femur width (HFW), vertex width (VW), compound eye width (CEW), and antennal length (AL).

RESULTS

Class Insecta Linnaeus, 1758

Order Orthoptera Latreille, 1793

Suborder: Caelifera Ander, 1939

Superfamily Tetrigoidea Rambur, 1838

Family Tetrigidae Rambur, 1838

Genus Xistra Bolívar, 1887

Subgenus Xistra Bolívar, 1887

Figure 1. Distribution and habitats of Xistra balinsasayaoensis sp. n.. A. Map of the Philippines; B. Map of Negros Island showing the location of Balinsasayao Twin Lakes Natural Park; C. The type locality (09°21'35.16"N, 123°10'53.52"E; 897–910 m a.s.l.).

Xistra balinsasayaoensis Patano, Skejo & Kasalo sp. nov.

https://zoobank.org/urn:lsid:zoobank.org:act:672ABD55-7A45-424D-ACE7-9959B21020E9

(Figs 2–3)

Diagnosis. The new species is most similar to X. gogorzae, from which it can be differentiated by having a wide vertex (nearly as wide as an eye in frontal view) (narrow in X. gogorzae, about half of eye width). The new species differs from X. sagittaria by having moderately high horns (very low in X. sagittaria) and very low undulations of the median carina at the level of the tegmina (undulations more pronounced in X. sagittaria).

Type Material. Holotype ♀, the PHILIPPINES, Negros Oriental, Sibulan, Balinsasayao Twin Lakes Natural Park, 09°21'35.16"N, 123°10'53.52"E; 897–910 m a.s.l., 28-X-2023, coll. R.R. Patano Jr. & V.B. Amoroso. With the following red label: ‘’HOLOTYPE, Xistra (Xistra) balinsasayaoensis Patano et al. 2026. Paratype: 1♂ with the following red label: ‘PARATYPE, Xistra (Xistra) balinsasayaoensis Patano et al. (Central Mindanao University, University Museum, Zoological Section).

Etymology. This new green-winged pygmy grasshopper species is named after its only known habitat, which is the Balinsasayao Twin Lakes Natural Park (BTLNP), one of the Long-Term Ecological Research (LTER) sites in the Philippines.

Distribution. New species is only known so far in the forested areas of Balinsasayao Twin Lakes Natural Park (BTLNP), Negros Oriental, Visayas, the Philippines.

Description. ¾ Female (Holotype) (Figs 2–3). 14.08 mm long from tip of vertex to tip of pronotum. Body green with dark and yellow markings. Femora and ovipositor brownish to reddish. Body surfaces shiny.

Head (Figs 2A–D). Antennae long and filiform with 16 segments (5.62 mm): 1st scape, 2nd pedicel, 3rd and 4th basal segments (0.25 mm) which are slightly longer than the second segment, 5th segment almost two-thirds of the size of the 6th segment, 7th and 8th segments almost identical in size, 9th to 11th almost two-thirds of the size of the 12th preapical segment, while the 12th segment almost two times and two-thirds longer than the 13th and 14th preapical segments, 15th segment two times larger than the 14th segment. 16th apical segment reduced. Head elongated. In frontal view, moderately elevated fastigial horns form with vertex a V-shape excision. Fastigial horns 0.17 mm high; tips of the fastigial horns elevated above the eye, surpassing its dorsal margins for about 1/7 of the compound eye height. In lateral view, head and especially eyes, slightly exserted above the pronotum. Antennal groove positioned low, 0.1 mm below the lower margin of the compound eye. Frontal costa extremely short, indistinct, and bifurcates into facial carinae at the middle of eye height, close to the tip of the vertex. Facial carinae diverge into 0.3 mm wide scutellum, as wide as scapus. Scutellum obliquely projected forwards. Lateral ocelli placed slightly above the lower margins of the compound eyes, slightly below the bifurcation of the frontal costa and clearly above the antennal grooves. Maxillary palps elongated, hairy, and yellowish to white in color. In dorsal view, vertex 1.52 times wider than eye. Medial carina of vertex distinct in the apical third.

Pronotum and wings (Fig. 3B). Dorsum of the pronotum smooth, almost entirely green with dark and yellow spots at anterior (surrounding sulci) scattered throughout the dorsum of the pronotum. Prozonal carinae short and parallel. Median carina low, forming low undulations above tegmina. Lateral lobes slightly directed sidewards but not forming ventrolateral projections. Visible part of tegmina dark with a white stripe in their dorsal part. Hind wings dark and slightly surpassing the pronotal apex.

Legs (Figs 2E–G, 2I, 3B). Fore and mid femora elongated and smooth, without significant undulations of their margins. Fore and mid tibae straight and smooth. Hind femora with small genicular and antegenicular teeth. Hind tibia straight with a few small teeth distally. First segment of hind tarsus slightly shorter than third; pulvilli on ventral side of first segment smooth, approximately equal in length.

Abdomen (Figs 2H, 3B). Abdomen smooth, generally brownish-green in coloration, but with darker markings all over itself. The widths of 1st to 5th abdominal segments range from 0.9 to 1.2. Subgenital plate in female has triangular excision on the tip, giving it a bilobate appearance. Ovipositor elongated, dorsal and ventral valves armed with about 10 strong teeth each.

Figure 2. Morphological details of Xistra balinsasayaoensis sp. n. (holotype, female). A. Head, frontal view; B–C. Head, lateral and dorsal views; D. Antennae; E. Hind femur; F. Hind tibia and tarsus; G. Mid femur; I. Fore femur; H. Abdomen, posterior part in lateral view. Scale bars 1 mm.

Figure 3. Xistra balinsasayaoensis sp. n. from Balinsasayao Twin Lakes Natural Park, Negros Island, Visayas, the Philippines. A–B. The female holotype; C–D. Male paratype. Scale bars 1 mm.

Male (Figs 3C–D). Similar to female, but smaller. The female and male specimens of the new species are morphologically quite uniform, with no major differences observed. However, it was observed that the female specimen has a more brownish to reddish coloration on its legs and abdomen than the single male specimen.

Local name. Balinsasayao’s horned pygmy grasshopper.

Measurements (in mm).

Female holotype (N=1). BL 15.35; PL 14.7; PW 3.9; PH 2.25; FFL 2.7; FFW 0.58; MFL 3.4; MFW 0.62; HFL 6.4; HFW 1.8; VW 0.57; CEW 0.72; AL 5.70.

Male paratype (N=1). BL 10.24; PL 12.22; PLW 3.12; PH 2.0; FFL 2.34; FFW 0.52; MFL 2.6; MFW 0.65; HFL 5.4; HFW 1.94; VW 0.53; CEW 0.62; AL 5.1.

Generic and subgeneric placement. The new species described herein is placed in the genus Xistra as it shares the following characters with known Xistra species (X. gogorzae, X. cristifera, X. sagittaria, X. corniculata, and X. derijei). Head slightly dorsoventrally elongated, eyes and vertex above the level of the pronotum. In the frontal view frontal costa bifurcation very high, with frontal costa itself being nearly invisible; X. cristifera being an exception with its short but visible frontal costa. Tip of the eyes visibly above the vertex. Lateral carinae projected as horns, which are in some species very low (X. sagittaria), in some moderate (X. gogorzae and X. balinsasayaoensis sp. nov.) while in others very high (X. corniculata, X. cristifera, and X. derijei). Antennal grooves positioned below the lower margins of the compound eyes. Paired ocelli below the middle level of the eyes, position varies depending on the degree to which the vertex is lowered below the eyes. Scutellum a bit (X. sagittaria, and X. balinsasayaoensis sp. nov.) or strongly widened (X. derijei). The new species is placed within the subgenus Xistra as it fits the following diagnosis of that subgenus, as presented in Skejo et al. (2025). Horns of the vertex weakly developed. Bifurcation of the frontal costa at the top of the face in anterior view, frontal costa nearly invisible. Top margins of the antennal grooves a little below the bottom margins of the eyes. The crest in the anterior part of the pronotum weakly developed.

DISCUSSION

Xistra balinsasayaoensis sp. nov. closely resembles X. gogorzae, differing from it most obviously by the width of the vertex. Apart from this, X. gogorzae has only been recorded in Libmanan and Mount Isarog, both located in the province of Camarines Sur, southern Luzon, which is not close to Mindanao or Negros Island (Cigliano et al. 2025). Given that X. gogorzae is currently known only from a few specimens, there is an urgent need to obtain fresh material for comprehensive morphological and molecular analyses. Other than the new species described herein, there are also some undescribed Xistra species awaiting description, all of which were recently observed and documented in some localities in Mindanao Island (Fig. 4). Specimens of Xistra (Xistra) balinsasayaoensis sp. nov. were observed and collected within the established 2-hectare permanent plot in Balinsasayao Twin Lakes Natural Park (BTLNP), Negros Island, the Philippines, the same locality where the Paraspartolus curiosus Günther, 1939, an endemic pygmy grasshopper, was recently recorded (Patano et al. 2024). However, after further examination, the P. curiosus from Negros is more likely a new species. It will be described as a new species in a future study. The area is a typical lower montane forest dominated by Ficus trees (Moraceae), with the understory dominated mostly by Alocasia spp. A single female specimen was observed perched on a tree trunk (Lauraceae) covered with some bryophytes, including some species of Neckeropsis of the family Neckeraceae (Figs 5–6). On the other hand, a single male specimen was collected from the tree trunk of the Ficus sp. The presence of the new species strengthens the importance of BTLNP as a protected area and one of the Long-Term Ecological Research (LTER) sites of the Philippines. Other than many species of arthropods, different species of endemic and threatened vascular plants can also be observed in the area (Aureo et al. 2021; Mendez et al. 2025).

Figure 4. Distribution of Xistra species within the Philippines, including undescribed species known exclusively from Mindanao Island.

Figure 5. Xistra balinsasayaoensis sp. n. and its respective microhabitats (tree trunks covered with bryophytes), dorso-lateral views of live specimens. A. Male; B. Female.

Figure 6. Microhabitat of Xistra balinsasayaoensis sp. n. in Balinsasayao Twin Lakes Natural Park, Negros Island. Specimens were observed. A. Old-growth secondary forest perched on B. Tree trunks (Lauraceae) covered with C. Bryophytes (Neckeropsis sp. of the family Neckeraceae).

AUTHOR′S CONTRIBUTION

The authors confirm their contribution to the paper as follows: R.R. Patano Jr: data curation, formal analysis, methodology, validation, writing, review, and editing the manuscript, and illustrations; J. Skejo: supervision, validation, writing, review and editing of the manuscript; V.B. Amoroso: supervision, writing, review and editing of the manuscript; F.P. Coritico: supervision, writing, review and editing of the manuscript; N. Kasalo: formal analysis, methodology, supervision, validation, writing, review & editing of the manuscript. The authors read and approved the final version of the manuscript.

FUNDING

This research received no specific grant from any funding agencies.

AVAILABILITY OF DATA AND MATERIAL

The specimens listed in this study are temporarily deposited in the Zoological Section of the University Museum of the Central Mindanao University, Southern Philippines, and will be deposited finally at the National Museum of the Philippines. The specimens are available from the curator upon request.

ETHICS APPROVAL AND CONSENT TO PARTICIPATE

This study only included arthropod material, and all required ethical guidelines for the treatment and use of animals were strictly adhered to in accordance with international, national, and institutional regulations. No human participants were involved in any studies conducted by the authors for this article.

CONSENT FOR PUBLICATION

Not applicable.

CONFLICT OF INTERESTS

The authors declare that there is no conflict of interest regarding the publication of this paper.

ACKNOWLEDGMENTS

The researchers would like to thank the Local Government Unit of the Municipality of Sibulan, the Department of Environment and Natural Resources, and the Balinsasayao Twin Lakes Farmers Association Incorporated of Sibulan, Negros Oriental. Most importantly, we thank the Commission on Higher Education (CHED) for funding the research project titled "Biodiversity Conservation and Utilization for Product Development (BioConUP) in Long-Term Ecological Research (LTER) Sites in Southern Philippines". In addition, the researchers would like to acknowledge Dr. Annabelle P. Villalobos, Dr. Alma B Mohagan, and also the president of Central Mindanao University, Dr. Rolito G. Eballe, for their outstanding support of the different research efforts implemented by the center (CEBREM). We thank Tomislav Domazet-Lošo and Damjan Franjević for reading an early version of the manuscript and providing valuable feedback. Lastly, we extend our sincere appreciation to Ms. Veronica Prudente and Dr. Jade Aster Badon for their invaluable assistance in providing preliminary taxonomic evidence of the new species described herein in Negros Island