Research Article Journal of Orthoptera Research 2023, 32(1): 55-62 Towards a betier understanding of the genus Scelimena (Orthoptera, Tetrigidae, Scelimeninae): New insights and notes on the taxonomy, ecology, and physiology of the genus in Peninsular Malaysia AmirA AQILAH MuxHAmmMApD!23, MAKS DERANJA?4, KARMELA Apbzic?4, NuruL ASHIKIN ABDULLAH! 1 Institute of Biological Sciences, Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia. 2 IUCN/SSC Grasshopper Specialist Group, Kuala Lumpur, Malaysia. 3 SIGTET—Special Interest Group Tetrigidae, Bonn, Germany. 4 IUCN/SSC Grasshopper Specialist Group, Zagreb, Croatia. Corresponding author: Amira Aqilah Muhammad (miamedulla@gmail.com) Academic editor: Ming Kai Tan | Received 13 August 2022 | Accepted 8 October 2022 | Published 18 April 2023 https://zoobank. org/A73E49F0-A2 DE-4F9F-9140-CDCC85D5CBAF Citation: Muhammad AA, Deranja M, Adzi¢é K, Abdullah NA (2023) Towards a better understanding of the genus Scelimena (Orthoptera, Tetrigidae, Scelimeninae): New insights and notes on the taxonomy, ecology, and physiology of the genus in Peninsular Malaysia. Journal of Orthoptera Research 32(1): 55-62. https://doi.org/10.3897/jor.32.91153 Abstract One of the two Scelimena Serville, 1838 species described from Peninsu- lar Malaysia, Scelimena gombakensis Muhammad, Tan & Skejo, 2018 occupies a wide distributional range across the country, contrary to the range described in the original description of the species. Extended research has shown that the species occurs in many localities in Peninsular Malaysia, which is inter- esting given that such findings are uncommon in the study of Tetrigidae. This paper provides new distribution localities, some ecological and physio- logical notes, and photographs of living specimens of Scelimena gombakensis. Other species synonymized here include Scelimena razalii Mahmood, Idris, & Salmah, 2007 syn. nov. of species Falconius dubius Giinther, 1938. Keywords citizen science, distribution, iNaturalist, pygmy grasshoppers, Scelimenini, Southeast Asia, synonymy Introduction Malaysian Tetrigidae still remains an understudied group of ani- mals since papers on them mostly highlight taxonomy, i.e., species description and occurrence. Examples of such papers from Penin- sular Malaysia are Mahmood et al. (2007), Tan and Kamaruddin (2014), Tan and Kamaruddin (2016), Skejo and Bertner (2017), Storozhenko and Pushkar (2017), and Muhammad et al. (2018). In Sabah and Sarawak, Ito and Mohamed (2001), Storozhenko (2012), Koéarek et al. (2015), and Skejo et al. (2019) also focused on tax- onomy, with the exception of a paper by Kuravova et al. (2017) that described Bornean Tetrigidae feeding patterns, offering an ecologi- cal insight. Other papers that briefly mention Malaysian Tetrigidae include Zha et al. (2016), Xin and Deng (2019), and Adzi¢ et al. (2020). One of the first papers to cover this family in Peninsular Ma- laysia was Mahmood et al. (2007). However, some misidentifications from the paper were reported in later publications (Storozhenko and Dawwrueng 2015, Muhammad et al. 2018), and certain species identifications from this paper require future revision. So far, only two Scelimena Serville, 1838 species have been found in Peninsular Malaysia (Cigliano et al. 2022): Scelimena razalii Mahmood, Idris & Salmah, 2007 and Scelimena gombakensis Muhammad, Tan & Skejo, 2018. While S. gombakensis belongs to the Scelimena discalis Hancock 1915 species group, S. razalii has not been assigned to any due to insufficient evidence and vague descriptions and drawings from Mahmood et al. (2007). Moreo- ver, it is only described in Kuala Lompat, Pahang, Malaysia. In this study, we synonymized Scelimena razalii Mahmood, Id- tis & Salmah, 2007 syn. nov. with Falconius dubius Gunther, 1938 after close examination of the type specimens of S. razalii. We also looked into the distribution of S. gombakensis by reporting on all known specimen observation localities and linking this updated distribution of the species with its ecological (i.e, habitat) and physiological (i.e., swimming ability) characteristics. Photos of both living and pinned specimens of S. gombakensis and EF. dubius, detailed scanning electron microscopy (SEM) photos of morpho- logical characters of hind leg tarsi and tibiae of S. gombakensis, and a distribution map of S. gombakensis are provided. Material and methods Institutional abbreviations. — CIS (UKM) Center for Insect Systematics, Universiti Kebang- saan Malaysia, Selangor, Malaysia; FRIM Forest Research Institute Malaysia, Peninsular Ma- laysia; MZUM (UM) Museum of Zoology, Universiti Malaya, Kuala Lum- pur, Malaysia; Zoological Reference Collection, Lee Kong Chian Natural History Museum, Singapore. ZRC Copyright Amira Aqilah Muhammad et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits un- restricted use, distribution, and reproduction in any medium, provided the original author and source are credited. JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1) 56 A.A. MUHAMMAD, M. DERANJA, K. ADZIC AND N.A. ABDULLAH Both physical records (specimen) and virtual records (online database) were assessed. Falconius dubius specimens were exam- ined at MZUM (UM) and CIS (UKM), whereas Scelimena gom- bakensis specimens were examined at MZUM (UM), ZRC, and FRIM. Photographs used in this manuscript were taken using an Olympus Compact Stereo Microscope SZ61 with an Olympus Microscope Digital Camera DP22 connected to a desktop com- puter during museum examination. A Canon EOS 600D camera with 100 mm f/2,8 macro lens attached was used for in situ pho- tography. Records of type specimens described in Muhammad et al. (2018) deposited in ZRC, MZUM, and FRIM were assessed by Amira Agilah Muhammad. Data screening on the iNaturalist website was done using the keywords “Scelimena gombakensis,” in which the online observations were additionally confirmed by the authors. Supplementary information (i.e., dates of publishing, lo- cation names, GPS coordinates, and website identification num- bers) are listed in Table 1. Only iNaturalist observation data avail- able prior to the date of this paper’s submission (29 August 2022) were included in this paper. The tabulated coordinates were input into QGIS version 3.16.13 to visualize the distribution on a map. Table 1. Observations of Scelimena gombakensis Muhammad, Tan & Skejo, 2018 specimens in Peninsular Malaysia found on iNaturalist platform (www.inaturalist.org) (the last column refers to iNaturalist observation ID). Observer Date Locality Coordinates Observation ID Fabio Cianferoni Jul. 4, 2008 Hulu Perak, Perak, Malaysia 5230"102N7- LOL 26se E 45968367 CheongWeei Gan Dee-5 2009 Hulu Yam, Selangor, Malaysia 3°24'11"N, 101°41'4"E 127199050 CheongWeei Gan Dec. 5, 2009 Hulu Yam, Selangor, Malaysia 3°19'55"N, 101°42'6"E 127199054 Phil Benstead Aug. 26, 2013 Hulu Langat, Selangor, Malaysia 3°7'48"N, 101°53'17"E 71201238 Erland Refling Nielsen Aug. 30, 2013 Gombak, Selangor, Malaysia 3°19'27"N, 101°44'54"E 63194111 Kees van Reenen Jan. 29,2019 Seremban, Negeri Sembilan, Malaysia 2°47'55"N, 101°48'3"E 35679667 Yiquan Chin Feb. 23, 2019 Timur Laut, Penang, Malaysia 5°26'2"N, 100°17'46"E 20687721 Alexius L.Z.L Dec, 19, 2019 Timur Laut, Penang, Malaysia §°25'54"N, 10071 7 55"E 36773269 Vatcharavee Sriprasertsil June 2021 Waeng, Narathiwat, Thailand 5°47'43"N, 101°49'42"E 84546541 Chloe Alison Dec. 14,2021 Genting Highlands, Pahang, Malaysia 3°24'40"N, 101°47'40"E 103086028 Alexius L.Z.L Dec. 11, 2021 Mukim 17, Penang, Malaysia 5°21'35"N;- 100° 29'32"E 102908617 Puteri Nuraida Syuhada Binti Abdullah — Dec. 11, 2021 Hulu Langat, Selangor, Malaysia 3 ADS FN; AGLE5O'33-4E 102847175 Albert Kang Mar. 1, 2022 Tanjung Bungah, Penang, Malaysia 5°27'54"N, 100°16'55"E 107814195 Aiman Azmi May 13, 2022 Pasir Puteh, Kelantan, Malaysia 5°45'49"N, 102°24'32"E 116921973 Field observation was done at the type locality—Ulu Gombak Field Study Center, Ulu Gombak, Selangor, Malaysia—where the authors focused on several aspects of tetrigid behavior during the daytime, including food preference and locomotion (utilization of legs and hindwings). Several individuals were collected and preserved in 95% ethanol to observe the leg structure under Hi- tachi’s Table Top Scanning Electron Microscope (SEM) TM3030. The specimens’ legs were mounted on a conductive double-sided tape on a specimen stub that was then set on a holder before the height level was adjusted by controlling the height gauge. The stage was then carefully placed in the chamber before closing, and the imaging process followed the instructions given by the user's manual. Scanned images were edited using TM3030 software in- stalled on a desktop computer connected to the SEM machine. Results Taxonomy Family Tetrigidae Rambur, 1838 Subfamily Scelimeninae Bolivar, 1887 Tribe Scelimenini Bolivar, 1887 Falconius dubius Gtinther, 1938 Falconius dubius Gunther, 1938: 399, 404, 419. Scelimena razalii Mahmood, Idris & Salmah, 2007, syn. nov. - Mahmood, Idris and Salmah 2007: 1279; Muhammad et al. 2018: 53; Maitlo and Panhwar 2021: 34. CIS (UKM) ¢ 2 ¢; Ulu Langat; 16 Mar. 1964; AAM leg.; MZUM IOt 002323, 002324 e 1 4; Ulu Langat; 7 Mar. 1964; AAM leg.; MZUM 1Ot 002353 ¢ 1 4G; Ulu Gombak Bt 16; 7 Mar. 1964; AAM leg.; MZUM IOt 002370 ¢ 1 2; same data as for preceding; MZUM IOt 002377 ¢ 1 3; Ulu Gombak; 15 July 2019; Adzic, K. leg.; MZUM ¢ 1 4; Ulu Gombak; 15 July 2019; Deranja, M. leg.; MZUM e@ 1 3; Ulu Gombak, 24 July 2019; Muhammad, A. A. leg.; MZUM @ 1 6; Ulu Gombak; 29 July 2019; Adzic, K. leg.; MZUM. ¢ 1 9; same data as for preceding. Negeri Sembilan ¢ 1 9; Negeri Sembilan, Pasoh; 26 June 1997; Rina Silviana leg.; MZUM IOt 002383. Pahang e 1 4G; Eko Rimba Lentang; 22 July 2019; Adzic, K. leg; MZUM e 1 9; Eko Rimba Lentang; 22 July 2019; Deranja, M. leg.; MZUM. Justification of the synonymy.—After examination of the Scelimena razalii Mahmood, Idris & Salmah, 2007 type material, we consider it to be a synonym of Falconius dubius Giinther, 1938. We found many Falconius Bolivar, 1898 specimens in the UKM collection, but none were identified as belonging to the genus Falconius as de- scribed in Mahmood et al. (2007). The genus can easily be distin- guished from other Scelimenini genera by the swollen hind tarsi in females (Fig. 1D, indicated by an arrow. Note that this character is present in Eufalconius Giinther, 1938 as well), a relatively stout head with the most prominent feature being the frontal costa fork- ing relatively close to the fastigium, the anterior margin of the eyes raised slightly above the fastigium, and a relatively high position of the paired ocelli and the antennal grooves in relation to the compound eyes (Bolivar 1898, Muhammad et al. 2018). Upon further comparison with photographs of the type material of E. dubius available on Orthoptera Species File (OSF) database, we found no differences between these two species. We cannot be cer- Material examined.—MALAYSIA, Selangor ¢ 2 ¢; holotype and tain that the S. razalii specimens reported from Pakistan (Maitlo paratype of Scelimena razalii; 24 July 2004; Rezwana Rezali leg.; and Panhwar 2021) also belong to this species because we did not JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1) A.A. MUHAMMAD, M. DERANJA, K. ADZIC AND N.A. ABDULLAH 97 Fig. 1. Specimens of Falconius dubius Giinther, 1938 from Peninsular Malaysia. A-C. Holotype of Scelimena razalii Mahmood, Idris & Salmah, 2007 syn. nov.; D. A female specimen from Universiti Malaya collection; E. The morphology of living specimens in their natural habitat in Ulu Gombak, Selangor, Peninsular Malaysia, both male and female. have the opportunity to examine this material. Hence, those speci- mens should be re-examined in the future. This paper is the first official record for the species from Pen- insular Malaysia (following data from Adzi¢ (2021); note that the type material specimens are listed incorrectly in the thesis, which is corrected in this paper) (Fig. 1). Scelimena gombakensis Muhammad, Tan & Skejo, 2018 Scelimena producta (Serville, 1838) - Mahmood et al. 2007: 1279; Storozhenko and Dawwrueng 2015: 543). Scelimena gombakensis Muhammad, Tan & Skejo, 2018: 6, 46. Examined material.—Holotype: PENINSULAR MALAYSIA, Selangor ¢ 1 g; Ulu Gombak Field Studies Centre; 24 Sept. 2017; Muham- mad, A. A., Muhammad Hafiz Mohd Amin & Afyza Maisarah Azi- zan leg.; ZRC. Paratypes: PENINSULAR MALAYSIA, Selangor ¢ 1 9; Ulu Gombak Field Study Centre; 9 Mar. 2018; Muhammad, A. A. & Abdullah, N. A. leg.; ZRC ¢ 1 @; same data as of preceding; FRIM ¢ 1 2; same data as of preceding; FRIM ¢ 2 3; same data as of preced- ing; MZUM e 1 2; Ulu Gombak Field Study Centre; 24 Sept. 2017; Muhammad, A. A., Muhammad Hafiz Mohd Amin & Afyza Maisa- rah Azizan leg.; FRIM @ 1 9; same data as of preceding; MZUM. Other material: PENINSULAR MALAYSIA, Selangor ¢ 8 <; Ulu Gombak; 7 Mar. 1964; AAM leg.; MZUM IOt 002350, 002351, 002355, 002361, 002362, 002366, 002367, 002369 © 3 9; same data as of preceding; MZUM IOt 002357, 002363, 002379 e 1 d; Ulu Gombak 16ms. [miles]; 27 May 1964; AAM leg.; MZUM IOt 002347 e 2 3; Ulu Gombak, 16ms. [miles]; 15 Apr. 1964; AAM leg.; MZUM IOt 002371, 002373 @ 1 3; Ulu Gombak, 12ms; 15 Apr. 1964, AAM leg.; MZUM IOt 002372 ¢ 3 3; Ulu Gombak, Bt [Batu] 16; 7 Mar. 1964; AAM leg.; MZUM IOt 002348, 002349, 002356 e 4 9; same data as of preceding; MZUM [Ot 002358 to 002360, 002365 ¢ 7 3; Ulu Langat; 16 Mar. 1964; AAM leg.; MZUM I0t 002333, 002334, 002340, 002342 to 002345 e 2 Q; same data as of preceding; MZUM IOt 002339, 002341 ¢ 1 9; Ulu Gombak; 15 Jul. 1969; JAB leg.; MZUM IOt 002428 e 1 4; Ulu Gombak; 15 Sept. 1974; Chua Eng Lok leg.; MZUM IOt 002407 e 1 3; same data as of preceding; L. Teo leg.; MZUM IOt 002408 ¢ 1 3; same data as of preceding; B. H.Voon leg.; MZUM [Ot 002415 e 1 2; same data as of preceding; Aru leg.; MZUM IOt 002413 @ 1 Q; same data as of preceding; K. C. Tung leg.; MZUM IOt 002414 e 1 9; Ulu Langat; 27 Oct. 1974; Wong Yow Sin leg.; MZUM IOt 002411, © 1 9; same data as of preceding; P. FE. K. leg.; MZUM IOt 002412 ¢ 1 9; Pansoon; 27 Oct. 1974; Heng. L. P. leg.; MZUM IOt 002409 e 1 9; same data as of preceding; Hoo Ah Teng leg.; JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1) 58 MZUM IOt 002416 ¢ 1 @; Sg. [Sungai] Tua; 27 July 1979; C. L. leg.; MZUM IOt 002406 e 1 9; Ulu Gombak; 1 Dec. 1982, Zurai- dah Mian leg.; MZUM [Ot 002388 e¢ 1 9; Ulu Gombak; 21 Oct. 1984; Daiqah leg.; MZUM IOt 002410 e 1 9; Ulu Gombak; 18 Sept. 1995; Hasleyza leg.; MZUM IOt 002386 ¢ 1 4; Ulu Gombak; 7 July 1997; Rosliza leg; MZUM IOt 002430 e 1 3; Ulu Gom- bak; MZUM [Ot 002391. Negeri Sembilan ¢ 1 ¢; Ulu Bendul; 12 Aug. 1989; ZZ leg.; MZUM IOt 002427. Pahang ¢ 1 <; Ketari; 7 June 1961; MZUM [Ot 002385 ¢ 1 9; same data as of preced- ing; MZUM [Ot 002387 ¢ 1 4; Nenasi; 17 Nov. 1974; W. C. Kang leg.; MZUM IOt 002404 e 1 9; Lentang; 2 Dec. 1995; Rohaya leg.; MZUM IOt 002426. Perak e 1 9; Grik; 17 Feb. 1991, McGyver leg.; MZUM I0t 002418 ¢ 1 3; Perlok; 20 May 1997, Khaironizam Md. Zain leg.; MZUM IOt 002399. Johor ¢ 1 3; Batu] Pahat; 20 Nov. 1974; M. Ali-S leg; MZUM IOt 002403 ¢ 1 ¢; Duhsun; 17 Nov. 1974; Salleh leg.; MZUM IOt 002417. Terengganu ¢ 1 3; Jerangau; 2 Mar. 1974; Baki leg.; MZUM [Ot 002405. Kelantan ¢ 1 3; Kg Senyul; 15 June 1962; KJK leg.; MZUM IOt 002375 ¢ 1 9; same data as of preceding; MZUM IOt 002374 e 1 Q; Flort] Brooke; 15 Apr.1962; JAB leg.; MZUM IOt 002381. iNaturalist observation.—PENINSULAR MALAYSIA, Perak e Hulu Perak; 5°30'10"N, 101°26'11"E; 4 July 2008; Fabio Cian- feroni leg.; iNaturalist.org: https://www.inaturalist.org/observa- tions/45968367. Selangor ¢ Hulu Yam; 3°24'1"N, 101°41'4"E; 5 Dec. 2009; CheongWeei Gan leg.; iNaturalist.org: https://www. inaturalist.org/observations/127199050 ¢ Hulu Yam; 3°19'55"N, 101°42'6"E; 5 Dec. 2009; CheongWeei Gan leg.; iNaturalist.org: https://www.inaturalist.org/observations/127199054 ¢ Hulu Lan- gat; 3°7'48"N, 101°53'17"E; 26 Aug. 2013; Phil Benstead leg.; iN- aturalist.org: https://www.inaturalist.org/observations/71201238 ¢ Gombak; 3°19'27"N, 101°44'54"E; 30 Aug. 2013; Erland Refling Nielsen leg.; iNaturalist.org: https://www.inaturalist.org/observa- tions/63194111 © Hulu Langat; 3°12'37"N, 101°50'33"E; 11 Dec. 2021; Puteri Nuraida Syuhada Binti Abdullah leg.; iNaturalist. org: https://www.inaturalist.org/observations/102847175. Negeri Sembilan ¢ Seremban; 2°47'55"N, 101°48'3"E; 29 Jan. 2019; Kees van Reenen leg.; iNaturalist.org: https://www.inaturalist.org/obser- vations/35679667. Penang © Timur Laut; 5°26'2"N, 100°17'46"E; 23 Feb. 2019; Yiquan Chin leg.; iNaturalist.org: https://www.in- aturalist.org/observations/20687721 ¢ Timur Laut; 5°25'54"N, 100°17'55"E; 19 Dec. 2019; Alexius L.Z.L leg.; iNaturalist.org: https://www.inaturalist.org/observations/36773269 ¢ Mukim 17; 5°21'35"N,, 100°29'32 °F" 11 Deci2021; Alexius'L.Z.L leg. iNatu- ralist.org: https://www.inaturalist.org/observations/102908617 e Tanjung Bungah; 5°27'54"N, 100°16'55"E; 1 Mar. 2022; Albert Kang leg.; iNaturalist.org: https://www.inaturalist.org/observa- tions/107814195. Pahang ¢ Genting Highlands; 3°24'40"N, 101°47'40"E; 14 Dec. 2021; Chloe Alison leg.; iNaturalist.org: https://www.inaturalist.org/observations/103086028. Kelantan e Pasir Puteh; 5°45'49"N, 102°24'32"E; 13 May 2022; Aiman Azmi leg.; iNaturalist.org: https://www.inaturalist.org/observa- tions/116921973. THAILAND, Narathiwat ¢ Waeng; 5°47'43"N, 101°49'42"E; June 2021; Vatcharavee Sriprasertsil leg.; iNaturalist. org: https://www.inaturalist.org/observations/84546541. Examination of the specimens deposited at FRIM, MZUM, and ZRC revealed that the species was previously known from the re- gion but was not recognized as a separate species. S. gombakensis had been wrongly identified by researchers as Scelimena producta (Serville, 1838) (Mahmood et al. 2007, D.K. McE. Kevan's notes on specimen labels in the UM collection). S. producta producta has been described from Java and has a similar body coloration A.A. MUHAMMAD, M. DERANJA, K. ADZIC AND N.A. ABDULLAH to S. gombakensis (see specimen photographs available on OSF). However, it can be morphologically differentiated by two char- acteristics: pointed tubercles at humeral angles to the pronotum (rounded in S. gombakensis) and numerous clearly visible teeth on the ventral side of its hind femora (while S. gombakensis has only two small teeth) (Muhammad et al. 2018). Thus, we correct previ- ous identifications and consider all listed specimens to belong to S. gombakensis, making these identifications new locality records for the species. Variability.—Thanks to the large number of specimens that we were able to examine, we found S. gombakensis to be a rather vari- able species, especially in terms of body size (4: 18.0-24.0 mm; Q: 24.0-31.0 mm). Nymphs do not differ much from adults, hav- ing similar coloration and general appearance, although they do have significantly shorter pronotum, making them easily distin- guished from other Tetrigidae in Peninsular Malaysia. During the fieldwork, we observed one specimen belonging to S. gombakensis with unique coloration—the specimen’s general body coloration was brown (opposed to the common dark green coloration) with orange markings (opposed to yellow markings; Fig. 2E, indicated by an arrow). This coloration could be recessive given its rarity, or it could be caused by some kind of infection. A change of coloration was also observed in pinned specimens (Fig. 2A-D), which is a very interesting but rarely mentioned ob- servation in Tetrigidae (an example of such observation was de- scribed by Mathieu et al. (2021)). In the MZUM collection, which holds a large number of S. gombakensis specimens, we observed color degradation in the older specimens. The colors of the older specimens were generally faded more than in recent ones, which gradually lost their dark green coloration with yellow markings and became generally brown in coloration. However, it is impor- tant to note that not all specimens had lost their color to the same extent, as some specimens from the 1960s are not as faded as the one represented in this paper (Fig. 2A). Since all the specimens were collected around the same time and were all stored in the same box under the same conditions, it is possible that pre-pin- ning conditions play a vital role in coloration preservation in S. gombakensis specimens. Such factors might be influenced by the sampling and euthanization methods, duration of pinning of the specimens, preservation techniques, etc. Since we did not have in- formation on the pre-pinning conditions older specimens were exposed to, this hypothesis requires consideration in the future. Distribution of S. gombakensis.—At first, it was hypothesized that this species would have general ecological traits similar to those of other Tetrigidae, including the fact that Tetrigidae are, in general, highly confined to water bodies, as they are often found in close proximity to fast-flowing rocky rivers (Tan et al. 2017). Even so, we have also observed specimens flying long distances and maneuver- ing well during flight. It is likely that this species, like many other Tetrigidae, is tightly linked to large flowing bodies of water and disperses passively by water during diving as an escape behaviour. With recently described species such as S. gombakensis, addi- tional knowledge on species distribution, behavior, and other aspects of the species’ ecology are frequently understudied and incomplete. Revisiting old specimens deposited in museums or private collections is thus an important next step in understanding a species, as these repositories might hold historical specimens be- longing to the species. Muhammad et al. (2018) stated that S. gom- bakensis is restricted to Sungai Gombak of the Gombak Catchment in Selangor, Peninsular Malaysia. Revision of specimens deposited JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1) A.A. MUHAMMAD, M. DERANJA, K. ADZIC AND N.A. ABDULLAH 1964. 1997. 2019. ae P Lae A MZUM 10t MZUM 101 002340 002430 § eMC alivags | Man 4onga7 pyr Vio Gombal Pp rises Big, Pelongon A re B B-Vi\~ 2549 | CG of (8-3-6 ham. leg, Muhammad AA aes: ; = - ; ; ~e s is": : 59 Fig. 2. Change of coloration in pinned specimens of Scelimena gombakensis Muhammad, Tan & Skejo, 2018 compared to the living specimen. A-C. Pinned S. gombakensis specimens; D. Living S. gombakensis specimens. E. Coloration variability and camouflage of three living S. gombakensis specimens; F. Natural habitat of S. gombakensis at the type locality Ulu Gombak, Selangor, Malaysia. JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1) 60 in museum collections (UKM, UM, FRIM, and ZRC) and photos on online databases have shown that the species is, in fact, widely dis- tributed across the country, especially along the West coast (Fig. 3). Social media observations on iNaturalist have greatly contributed to understanding species distribution (Table 1), once again dem- onstrating how useful citizen science can be (for other examples of the contributions of citizen science to the study of Tetrigidae, see Skejo et al. 2019, Kasalo et al. 2021, and Pavlovic¢ et al. 2022). S. gombakensis is an example of a species that is easily recog- nized through photographs and highly unlikely to be misidentified in Peninsular Malaysia, making identification using iNaturalist very reliable. Additionally, thanks to iNaturalist, we were able to discover an observation of S. gombakensis in the Waeng district of Narathi- wat, Thailand, very close to the border of Peninsular Malaysia; this represents the first official record of the species outside of Peninsu- lar Malaysia, making this the first record for the country (Fig. 3, Ta- ble 1). Further clarification of the species’ distribution is possible by comparing this species with Scelimena discalis Hancock, 1915 speci- A.A. MUHAMMAD, M. DERANJA, K. ADZIC AND N.A. ABDULLAH mens from Thailand (Storozhenko and Dawwrueng 2015), which may include some misidentified specimens. For now, we refrain from comparing S. gombakensis to S. discalis due to the inaccessibil- ity of physical specimens and the lack of molecular and online data. Ecology and habitat of Scelimena gombakensis.—Muhammad¢d et al. (2018) noted that S. gombakensis can be found perched on river rocks in lowland secondary rainforest where it is cool and very hu- mid, especially in areas shadowed by tree canopies. Further field ob- servation revealed that high moisture and indirect sunlight may be key to their survival, in tandem with the abundance of lichens and mosses that are their food source (Zha et al. 2017). On the rocks, S. gombakensis tends to crowd near the water surface, where the high turbidity of the flowing stream creates a suitable humid biota. Juve- niles are more likely to be observed close to the water surface than adults, as they are more susceptible to desiccation due to their im- mature exoskeletons. The juveniles are also less agile and unable to fly; hence, staying close to the water surface might increase their Malaysia q Ww Type locality MZUM specimens records © iNaturalist records Fig. 3. Distribution map of species Scelimena gombakensis Muhammad, Tan & Skejo, 2018 based on museum collection and iNaturalist data. JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1) A.A. MUHAMMAD, M. DERANJA, K. ADZIC AND N.A. ABDULLAH 61 Fig. 4. Scanning electron micrographs of the hind leg of S. gombakensis in ventral view. A. Hind tibia; B. First tarsal segment; C. Magni- fied view of the serration lining the edges of both tibia and tarsal segment; D. Tarsal claw. Scale bars: 100 pm (A, B); 50 ym (C, D). success rate when escaping from predators by diving underwater. Al- though individuals of various life stages can be found on the same rock, the place where S. gombakensis lays their eggs remains a mys- tery. For some Scelimena species, it is speculated that the eggs are laid elsewhere, such as in the sand along the riverbanks, and are perhaps well adapted to waterlogged conditions (Zha et al. 2017). Physiology of Scelimena gombakensis as key to adaptation to a semi- aquatic environment.—Closer observation of the characteristics of the hind legs of S. gombakensis elucidates their swimming abil- ity (Fig. 4). A close-up of the insect’s hind tibia and its first tarsal segment under a scanning electron microscope (SEM) reveals the following hydrodynamic characters: the first tarsal segment is later- ally compressed along the whole length, and serration exists along the lateral edges of both the first tarsal segments and the hind tibi- ae (Fig. 4A, B, C). The lateral compression provides a wider surface area for paddling underwater and likely aids in better propulsion during swimming. The serration along the lateral edges could serve multiple functions, but the tarsal serration most likely enhances the legs’ grip on wet and slippery rock surfaces since the arolium is absent underneath the claws (Fig. 4D). Thus, the presence of mi- croscopic serrations means porous rock surfaces offer more grip to the species’ limbs. Morphologically similar to riblet-like shark skin, another possible function of the serrations is to improve hydrody- namics by reducing the water drag acting upon its serrated tibiae when propelling underwater, reducing the formation of vortices and making swimming more energy efficient. The orientation of both microscopic structures is also parallel to the flow of water, hinting at functional homology (Han et al. 2008, Zhang et al. 2011). Our observations suggest that S. gombakensis utilizes both its hind legs and hindwings for navigation and survival, unlike Sce- limena songkrana Zha & Wen, 2017 from Thailand, which seldom flies but often jumps, as described by Zha et al. (2017). On the other hand, Scelimena melli Gunther, 1938 from China behaves similarly to S. gombakensis except for the fact that S. melli leaps further (for 10 meters or more). The mating behavior of S. gom- bakensis is consistent with that of other Scelimena (Zha et al. 2017), in which the male securely positions itself on top of the female. Conclusions Scelimeninae of Peninsular Malaysia is poorly known because few specimens have been collected in the region, and comprehen- sive taxonomic research of pygmy grasshoppers in the region is lack- ing. The short discussion on Scelimena razalii given in this paper has resulted in its synonymisation with Falconius dubius. The authors recognize only one valid species of the genus Scelimena as inhabit- ing the region, although further research is likely to result in the dis- JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1) 62 covery of new species. Likewise, Scelimena gombakensis was found to have a wider distribution range than originally considered, and it is expected that new localities will be discovered with further research. In this paper, we summarized a wide array of information concern- ing the ecology and physiology of S. gombakensis and provided com- ments and hypotheses that should serve as inspiration and motiva- tion for further research of this genus in Peninsular Malaysia. Acknowledgments The authors are grateful to all the museums and institutes for their cooperation with the examination of additional materials from their collections, especially Muzium Zoologi (MZUM), Uni- versiti Malaya and Centre for Insect Systematics (CIS), Universiti Kebangsaan Malaysia. Further thanks are given to Dr. Noorhidayah Mamat for assisting with the SEM handling and micrography and to Dr. Josip Skejo and Niko Kasalo for proofreading the paper and giving valuable suggestions. We are also grateful to all those who uploaded their observations to the iNaturalist platform, thus im- proving this paper by giving the authors valuable information on species distribution and refining the knowledge of tetrigidology in Peninsular Malaysia. Last but not least, we would like to thank The Orthopterists’ Society for providing free publication of this paper and the journal’s reviewers for improving the paper with their comments and suggestions. References Adzi¢ K (2021) Pygmy Grasshoppers (Orthoptera: Tetrigidae) of Peninsu- lar Malaysia. Master's thesis, Zagreb, Croatia: University of Zagreb. Adzi¢ K, Deranja M, Franjevi¢ D, Skejo J (2020) Are Scelimeninae (Orthop- tera: Tetrigidae) monophyletic and why it remains a question? Ento- mological News 129: 128-146. https://doi.org/10.3157/021.129.0202 Bolivar I (1898) Contributions a l’etude des Acridiens. Especes de la faune Indo et Austro-Malaisienne du Museo Civico di Storia Naturale di Genova. Ann. Mus. Civ. Stor. nat. Genova 19: 66-101. https://doi. org/10.5962/bhl.part.9541 Cigliano MM, Braun H, Eades DC, Otte D (2022) Orthoptera Species File. Version 5.0/5.0. [last accessed on August 29, 2022] http://Orthoptera. SpeciesFile.org Ginther K (1938) Revision der Acrydiinae, I. Sectiones Tripetalocerae, Dis- cotettigiae, Lophotettigiae, Cleostratae, Bufonidae, Cladonotae, Sceli- menae verae. Mitteilungen aus dem zoologischen Museum in Berlin 23: 299-437. Han X, Zhang D, Li X, Li Y (2008) Bio-replicated forming of the biomimetic drag-reducing surfaces in large area based on shark skin. Chinese Science Bulletin 53: 1587-1592. https://doi.org/10.1007/s11434-008-0219-3 Hancock JL (1915) V. Indian Tetriginae (Acrydiinae). Records of the Indian Museum 11: 55-138. https://doi.org/10.26515/rzsi/v11/i1/1915/163610 Ito G, Mohamed M (2001) A preliminary report on functional morphol- ogy of 2 pygmy grasshopper species (Orthoptera: Tetrigidae). Nature and Human Activities 6: 65-66. Kasalo N, Deranja M, Adzic¢ K, Sindaco R, Skejo J (2021) Discovering insect species based on photographs only: The case of a nameless species of the genus Scaria (Orthoptera: Tetrigidae). Journal of Orthoptera Research 30: 173-184. https://doi.org/10.3897/jor.30.65885 Koéarek P, Kufavova K, Musiolek D, Wahab RA, Kahar SRA (2015) Syn- onymy of Discotettix adenanii Mahmood, Idris & Salmah, 2007 with D. belzebuth (Serville, 1838) (Orthoptera: Tetrigidae). Zootaxa 4057: 288-294. https://doi.org/10.11646/zootaxa.4057.2.10 Kuravova K, Sipo’ J, Wahab RA, Kahar SRA, Koéarek P (2017) Feeding pat- terns in tropical groundhoppers (Tetrigidae): a case of phylogenetic di- etary conservatism in a basal group of Caelifera. Zoological Journal of the Linnean Society 179: 291-302. https://doi.org/10.1111/zoj.12474 A.A. MUHAMMAD, M. DERANJA, K. ADZIC AND N.A. ABDULLAH Mahmood K, Idris AB, Salmah Y (2007) Tetrigidae (Orthoptera: Tetrigoi- dea) from Malaysia with the description of six new species. Acta Ento- mologica Sinica 50: 1272-1284. Maitlo M-u-N, Panhwar WA (2021) Pygmy grasshoppers (Tetrigidae: Or- thoptera) from district Naushahro Feroze, Sindh Pakistan. Journal of Entomology and Zoology Studies 9: 30-34. Mathieu E, Pavlovi¢é M, Skejo J (2021) The true colours of the Formida- ble Pygmy Grasshopper (Notocerus formidabilis Gunther, 1974) from the Sava region (Madagascar). ZooKeys 1042: 41-50. https://doi. org/10.3897/zookeys. 1042.66381 Muhammad AA, Tan MK, Abdullah NA, Azirun MS, Bhaskar D, Skejo J (2018) An annotated catalogue of the pygmy grasshoppers of the tribe Scelimenini Bolivar, 1887 (Orthoptera: Tetrigidae) with two new Sce- limena species from the Malay Peninsula and Sumatra. Zootaxa 4485: 1-70. https://doi.org/10.11646/zootaxa.4485.1.1 Pavlovic M, Boziéevi¢ L, Adzi¢ K, Deranja M, Franjevic D, Skejo J (2022) “Threatened Tetrigids Online”: Assessing Pygmy Rainforests Before They are Gone. Poster, European Congress on Orthoptera Conserva- tion (ECOC III), Leiden (Netherlands), April 2022. Serville JGA (1838) Histoire naturelle des insectes Orthopteres. Librairie Encyclopédique de Roret, Paris, 1-776. https://doi.org/10.5962/bhl. title.95609 Skejo J, Bertner P (2017) No more dust and exoskeletons—in vivo pho- tographic records provide new data on Eufalconius pendleburyi Gunther, 1938 (Orthoptera: Tetrigidae) from the Titiwangsa Mts. Annales Zoologici 67: 665-672. https://doi.org/10.3161/00034541A NZ2017.67.4.003 Skejo J, Gupta SK, Chandra K, Panhwar WA, Franjevi¢ D (2019) Orien- tal macropterous leaf-mimic pygmy grasshoppers—genera Oxyphyl- lum and Paraphyllum (Orthoptera: Tetrigidae) and their taxonomic assignment. Zootaxa 4590: 546-560. https://doi.org/10.11646/ zootaxa.4590.5.3 Storozhenko SY (2012) A new genus of the subfamily Metrodorinae (Or- thoptera, Tetrigidae) from Borneo. Euroasian Entomological Journal 11: 131-134. https://doi.org/10.11646/zootaxa.3647.1.5 Storozhenko SY, Dawwrueng P (2015) New and little-known pygmy grass- hoppers (Orthoptera: Tetrigidae) from Thailand. Zootaxa 4052: 527- 554. https://doi.org/10.11646/zootaxa.4052.5.2 Storozhenko SY, Pushkar TI (2017) A new genus of pygmy locusts (Orthoptera: Tetrigidae: Cladonotinae) from the Malay Peninsula. Annales Zoologici 67: 47-53. https://doi.org/10.3161/00034541A NZ2017.67.1.006 Tan MK, Kamaruddin KN (2014) Orthoptera of Fraser's Hill, Peninsular Malaysia. Lee Kong Chian Natural History Museum, National Univer- sity of Singapore, Singapore, 88 pp. Tan MK, Kamaruddin KN (2016) A contribution to the knowledge of Orthoptera diversity from Peninsular Malaysia: Bukit Larut, Perak. Zootaxa 4111: 21-40. https://doi.org/10.11646/zootaxa.4111.1.2 Tan MK, Yeo H, Hwang WS (2017) Ground dwelling pygmy grasshop- pers (Orthoptera: Tetrigidae) in Southeast Asian tropical freshwater swamp forest prefer wet microhabitats. Journal of Orthoptera Re- search 26: 73-80. https://doi.org/10.3897/jor.26.14551 Xin L, Deng W (2019) A new species and a new record of Xistrella from China (Orthoptera: Tetrigidae). Acta Entomologica Musei Nationalis Pragae 59: 453-462. https://doi.org/10.2478/aem- np-2019-0034 Zha LS, Sheng M, Wen TC, Hyde KD (2016) A new species and a revised key of the genus Thoradonta (Orthoptera, Tetrigidae). ZooKeys 607: 69-79. https://doi.org/10.3897/zookeys.607.9056 Zha L, Yu F Boonmee S, Eungwanichayapant PD, Wen T (2017) A new spe- cies of the genus Scelimena (Orthoptera: Tetrigidae) in Thailand and notes on its biology and ecology. Entomological News 126: 372-382. https://doi.org/10.3157/021.126.0505 Zhang DY, Luo YH, Xiang LI, Chen HW (2011) Numerical simulation and experimental study of drag-reducing surface of a real shark skin. Jour- nal of Hydrodynamics 23: 204-211. https://doi.org/10.1016/S1001- 6058(10)60105-9 JOURNAL OF ORTHOPTERA RESEARCH 2023, 32(1)