Zootaxa 4418 (1): 093–097 ISSN 1175-5326 (print edition) http://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2018 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4418.1.6 http://zoobank.org/urn:lsid:zoobank.org:pub:E90A4390-1F7A-4604-8D8E-835E63F12739
Nymph inadvertently described as new species for a fourth time? On the identity of Euscelimena hardi (Tetrigidae: Scelimeninae) with general remarks on the identification of pygmy grasshopper nymphs
JOSIP SKEJO1,2,5, SUNIL KUMAR GUPTA1,3 & JOSEF TUMBRINCK1,4 1SIGTET—Special Interest Group Tetrigidae
Abstract
Euscelimena hardi Gupta et Chandra, 2018 was described earlier this year from Chhattisgarh (India) as a unique species within the genus, characterized in small size, long pronotal projections, and a lack of wings. In this commentary we pro- vide evidence that E. hardi is a nymph of E. harpago (Serville, 1838), hence a new synonymy is proposed: Euscelimena harpago (Serville, 1838) = Euscelimena hardi Gupta et Chandra, 2018 syn. nov. Since this is the fourth time a nymph of Euscelimena Günther, 1938 has been described as a new species, we present general remarks on how to distinguish pygmy grasshopper nymphs and adults. Presence of a groove on the dorsal margin of the hind femora, directly before the knee (separating antegenicular and genicular teeth) is the only definite feature to separate nymphs from adults in brachypronotal or micropronotal wingless species. In macropterous species, morphology of tegmina and alae is helpful to separate nymphs from adults, nymphs having alae rich in radial venation in front of tegmina, while in adults tegmina are in front of developed alae. When dealing with a potential new species, researchers should firstly take into account known pygmy grasshoppers fauna of the studied area via Orthoptera Species File Online database Complex search (with imput Scope of search: Tetrigidae, Place name from geographic hierarchy: continent or country name).
Key words: Orthoptera, antegenicular, adult, tegmina, alae, misidentification, E. harpago, new synonymy
Introduction
Earlier this year, Gupta & Chandra (2018) described Euscelimena hardi (Fig. 1C), a new species of the genus Euscelimena Günther, 1938, from Chhattisgarh (India). Contrary to other Euscelimena species, E. hardi is small, apterous and has high pronotal projections. In the paper, some misinformation was presented, which is corrected here. In addition, general remarks for the identification of nymphs are given, so that authors in the future could have a reference point for the recognition of nymphs.
Commentary on Gupta & Chandra (2018)
1 In the title, Gupta & Chandra cited ‘Bolívar 1887’ as the author of the genus Euscelimena, however Günther described the genus within his revision of Scelimeninae in 1938. 2 There are currently three valid species in the genus and six accompanying synonyms. These are: (i) E. gavialis (Saussure, 1862) [synonyms Scelymena nodosa Walker, 1871, Scelimena spinata Hancock, 1915, and Abbasia subserrata Kirby, 1914—Fig. 1G] from the southernmost India and Sri Lanka, (ii) E. harpago (Serville, 1838)—Figs. 1A, 1B, [1C], 1D [synonyms Scelymena contracta Walker, 1871, Gryllus (Locusta) femorata Stoll,
Accepted by M. Pocco: 8 Mar. 2018; published: 4 May 2018 93 1813 and Tetrix uncinata Serville, 1838] widely distributed in India, and (iii) E. logani (Hancock, 1904) endemic to Sri Lanka. 3 There are numerous localities in Chhattisgarh where E. harpago is present, for example Bastar, Bilaspur, Kabirdham, Raipur and Surguja (Gupta 2016, Gupta & Chandra 2017). Identification of macropterous adult specimens from those localities is confirmed by the first author. 4 Important diagnostic features of the genus Euscelimena (see Fig. 1) are: (i) narrow vertex with V-shaped carinae (Fig. 1A) (ii) large lateral ocelli, (iii) elongated antennae (Figs. 1A, 1B), (iv) visible interhumeral carinae (Fig. 1A), (v) strong ventrolateral spine (Fig. 1A), (vi) fore and mid femora with visible teeth on dorsal and ventral margins (Fig. 1B), (vii) hind femora with strong teeth on its dorsal margin (Figs. 1B, 1C, 1D), (viii) tibia of the hind leg significantly widened towards the apex (Fig. 1A), (ix) first segment of the hind tarsi significantly longer than the third (Fig. 1B), (x) pronotum and alae long (Figs. 1A, 1B), (xi) tegmina large and oval (Fig. 1B), (xii) pronotum in adults bears low projections (promedial—PM, metamedial—MM, metamediolateral—MML) (Figs. 1A, 1B), in nymphs higher projections (Figs. 1C, 1G) (consult e.g. Günther 1938, Blackith 1992). 5 Chandra & Gupta (2018) stated for E. hardi ‘Tegmina [were] reduced, not visible, covered by pronotum, [while] alae [were] present, visible under pronotum, [and did] not reach the apex of the pronotum.’, but from the holotype and paratype photos it is visible that alae have radial venation, meaning they are not fully developed, which indicates that the specimens are immature. 6 From the photos it is visible that specimens lack a clear groove on the dorsal line of the hind femora (Fig. 1C, compare with Fig. 1E)—the groove defining genicular and antigenicular teeth (Fig. 1D, compare with Fig. 1F), a feature crucial to determine adult tetrigids and especially useful in separating nymphs from brachypronotal wingless species. 7 All the evidence supports that Gupta & Chandra (2018) misidentified nymphs of E. harpago for a new species of Euscelimena. The identical error happened three times already—to Serville (1838) with description of Tetrix uncinata based on female nymph of E. harpago from Bombay, to Walker (1871) with description of Scelymena contracta based on a female nymph of E. gavialis from [South] India, and to Kirby (1914) with description of Abbasia subserrata Kirby, 1914 (Fig. 1G) based on a nymph from Kerala. All the aforementioned authors have already confirmed that nymphs of Euscelimena spp. have higher pronotal projections than adult animals.
Conclusion. Euscelimena hardi Gupta et Chandra, 2018 syn.nov. is junior subjective synonym of Euscelimena harpago (Serville, 1838).
Taxonomy
Euscelimena harpago (Serville, 1838) (Figures 1A, 1B, 1C, 1D)
Tetrix harpago: Serville 1838: 763 (types from India: Maharashtra: Bobbay [=Mumbai] should be deposited in MNHN Paris, but JS did not find them); Euscelimena harpago: Günther 1938: 363; Scelymena contracta: Walker 1871: 841 (holotype female from Hindustan deposited in BMNH London), synonymyzed with Scelymena uncinata (Serville, 1838) by Kirby (1914); Gryllus (Locusta) femoratus Stoll 1813: 31 (type locality unknown), synonymized with Scelymena harpago (Serville, 1838) by Bolívar (1887). Tetrix uncinata Serville, 1838: 763 (female type from India: Maharashtra: Bobbay [=Mumbai] should be deposited in MNHN Paris, but JS did not find them), synonymized with Euscelimena harpago (Serville, 1838) by Blackith (1992) (but he didn’t see the types). Euscelimena hardi Gupta et Chandra, 2018: 44 (holotype male nymph from India: Chhattisgarh: Raipur: Barnawapara Wildlife Sanctuary: Hardi Nala deposited in NZSI Calcutta) syn. nov. of Euscelimena harpago (Serville, 1838).
How to reliably distinguish pygmy grasshopper nymphs from adults?
Since the first papers on pygmy grasshoppers’ taxonomy (e.g. Walker 1871, Bolívar 1931) (e.g. Liang 1990, Zheng 2005), there has been a consistent confusion in distinguishing pygmy grasshoppers nymphs from adults, especially
94 · Zootaxa 4418 (1) © 2018 Magnolia Press SKEJO ET AL. FIGURE 1. A–F. A—Euscelimena harpago (Serville, 1838) adult male dorsal view B—E. harpago adult male lateral view (A and B photograph by H. Song), C—holotype of E. hardi syn. nov. of E. harpago lateral view (photograph by S. K. Gupta), D—E. harpago hind femur (photograph by H. Song), E—drawing of the nymphal hind femur in Tetrigidae, F—drawing of the adult hind femur in Tetrigidae (E and F J. Tumbrinck), G—holotype of Abbasia subserrata Kirby, 1914, synonym of E. gavialis (Saussure, 1862) (photograph by J. Tumbrinck).
EUSCELIMENA HARDI AND TETRIGIDAE NYMPHS Zootaxa 4418 (1) © 2018 Magnolia Press · 95 adults of brachypronotal, apterous taxa. There are four general rules one must keep in mind when identifying pygmy grasshoppers, specifically:
8 Adult pygmy grasshoppers (Tetrigoidea: Tetrigidae) always have a groove (Figs. 1D, 1F) on the dorsal margin of the hind femora, directly before the knee. This groove separates two teeth—antegenicular tooth, just before the knee, and genicular tooth—on the knee. In nymphal instars there are no grooves (Figs. 1C, 1E), thus antegenicular and genicular teeth are not defined, and the dorsal margin of the hind femora is continuous. This is the only definite feature to separate nymphs from adults in brachypronotal or micropronotal wingless species. 9 In the last moulting, the grasshoppers’, crickets’, and bush-crickets’ (insects of the order Orthoptera, including pygmy grasshoppers), fore (= tegmina) and hind wings (= alae) swap their position. Before the swap, alae cover the tegmina (Fig. 1G). Therefore, in winged pygmy grasshopper species, tegmina are visible for the first time only in the adult state (Fig. 1B). 10 Alae of the nymphs have radial venation, without cross-veins (Fig. 1G). Fully developed alae of adults have rich cross-venation between the main veins, which are not radial as in nymphs. 11 Nymphs are smooth, soft and can be easily mashed. Adults have tougher integument. This feature is applicable to identifying living nymphs, but is not always reliable and should be taken with caution.
When dealing with potential new species of pygmy grasshoppers one should be familiar with Tetrigidae fauna (diversity) of the studied area. The best way is by making ‘preliminary lists’ of potential genera and species. Orthoptera Species File (shortened OSF, Cigliano et al. 2018) has many search options and one can search taxa by geographic area, availability of images and sound recordings, synonyms etc. Complex search within OSF is available at the link http://orthoptera.speciesfile.org/Common/editTaxon/SearchForTaxon.aspx. Complex Tetrigidae browsing by area can be performed quickly by 1) entering ‘desired’ taxon (it can be a family-group name, a genus-group name or a species-group name) in Scope of search and 2) entering ‘desired’ locality name (it can be a continent, a country or an even lower geographic level) in Place name from geographic hierarchy (one must additionally click Find place button), 3) submit search and 4) examine the morphology of listed species in relevant literature. For example, if one wants to check Cladonotinae of Sri Lanka (Search imput: Scope of search Cladonotinae, Geographic level 4 Sri Lanka), 7 species are enlisted within 4 genera (Cladonotus Saussure, 1862, Deltonotus Hancock, 1904, Gignotettix Hancock, 1909, Tettilobus Hancock, 1909) (Cigliano et al. 2018 accessed 20 February). In this way, researchers can make preliminary lists and compare whether their new material is similar to any known material, thus critically approaching Tetrigidae taxonomy.
Acknowledgements and authors’ contribution
Holger Braun shared with members of the Facebook group ‘SIGTET—Special Interest Group Tetrigidae’ the paper by Gupta & Chandra (2018) with note ‘Happy New Year! First new pygmy grasshopper from 2018, Euscelimena hardi.’ JS and JT recognized that Gupta and Chandra (2018) dealt with E. harpago nymph and instantly wrote this commentary. JS and JT are authors of equal contribution to this commentary. SKG was informed about the true identity of his new species and afterwards he checked the type specimens again, confirming that the alleged species was a synonym of E. harpago. JS and JT found it important to include the species’ author, who agrees with its synonymy, as a coauthor of this commentary. Thanks to Sara Stermšek and Holger Braun for checking the early version, and to Fran Rebrina for checking English in the final version of the manuscript. Thanks to Hojun Song for providing good photos of E. harpago adults. Thanks to reviewers for their comments that made the paper more understandable.
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