Introduction
Wide-nosed pygmy grasshoppers (Tetrigidae, Cladonotinae) include species of rather unique morphology, but their taxonomy was pretty chaotic till recently (Tumbrinck 2014). With the photographs of the name-bearing specimens becoming publicly available online on websites such as Orthoptera Species File (Cigliano et al. 2022), it is becoming easier to assess the taxonomy of old species and to identify new records.
The tribe Choriphyllini was established recently (Silva et al. 2019) to gather all leaf-like Cladonotinae from the Caribbean region. The tribe includes only two genera, Choriphyllum Serville, 1838 and Phyllotettix Hancock, 1902b, currently with three and four species, respectively. Starting with the description of P. rhombeus (Felton, 1765), one of the oldest Tetrigidae species from the standpoint of nomenclature, originally described as Cicada rhombea and all the way up to the review by Silva et al. (2019), the members of this group went through numerous taxonomic changes and some challenges have persisted up to today. The aim of this study is to establish a firm starting point for any future work on the tribe Choriphyllini. This is done through an extensive literature overview, a critical re-examination of the data and thoroughly-discussed taxonomic changes.
Materials and methods
Original descriptions (Serville 1838; Bolívar 1887; Hancock 1902a, b; Perez-Gelabert and Otte 1999) of all the species were consulted and type specimens (or photographs of type specimens) of all the described species were examined. Previous synonymisation (Kirby 1910) and nomen dubium designation (Silva et al. 2019) were re-checked and are discussed. A new record of Phyllotettix compressus (Thunberg, 1815) from iNaturalist and new records of Choriphyllum sagrai Serville, 1838 from the field and from museum collections are included. One new species is proposed, C. wallaceum Skejo, Kasalo & Yong, sp. nov. from Cuba, based on a male holotype from MNCN. Taxonomy follows the recent classification of Cladonotinae used in the Orthoptera Species File (Silva et al. 2019; Cigliano et al. 2022; Deranja et al. 2022). Terminology and measurements follow Devriese (1999) and Tumbrinck (2014), except that we introduce the term capital sinus for the sinus between the anterior projection of the pronotal crest and the lateral vertical edge of prozona/paranota (see Fig. 3). The most important taxonomic character in Choriphyllum and Phyllotettix is the shape and undulation of the pronotal crest, i.e. (a) the shape of the anterior projection, (b) the position of the highest point and (c) the shape of the pronotal tip.
The measurements were made using the ImageJ (v. 1.53t) software (Schneider et al. 2012). The information on the size of the specimens represented by drawings in Westwood (1839) was deduced using the information in the text (8 lines = 18 mm).
For each genus, we propose a vernacular name, list synonyms and type species and present composition, distribution and a brief generic diagnosis. For the new subgenus, we designate the type species, propose vernacular names and present composition, distribution and brief diagnoses. We define a species group as a category containing species with many similarities, but also with enough differences that make synonymisation impractical without more evidence; the specific status of each species is preserved and their close relationships are reflected by the groupings. For each species group, we propose a vernacular name and provide annotated distribution data and a brief diagnosis. For each species, we propose a vernacular name, present detailed taxonomic and nomenclatural history, information on type specimens and new records, annotated distribution data and a brief diagnosis.
Museum abbreviations are listed as follows:
ANSPAcademy of Natural Sciences, Philadelphia, Pennsylvania, USA;
BMNH The Natural History Museum [British Museum of Natural History], London, UK;
FSCADivision of Plant Industry, Florida State Collection of Arthropods, Florida, USA;
FZ Fernando de Zayas private collection (formerly at Havana, Cuba, current whereabouts unknown);
IES Instituto de Ecología y Sistemática, La Habana, Cuba;
MfNMuseum für Naturkunde, Berlin, Germany;
MHNGMuséum d’Histoire Naturelle, Geneva, Switzerland;
MNCNMuseo Nacional de Ciencias Naturales, Madrid, Spain;
MNHNMuséum national d’Histoire naturelle, Paris, France;
MNHNC Museo Nacional de Historia Natural Cubana, Havana, Cuba;
OSF Orthoptera Species File; SY – Personal collection of Sheyla Yong, Havana, Cuba;
UZIUUppsala University, Uppsala, Sweden.
Discussion
World’s largest tetrigid “comes home”
Phyllotettix (Rhombotettix) rhombeus (Felton, 1765), a species first assigned to Cicada (Felton 1765; Linnaeus 1767), then to Membracris (Fabricius, 1775), Hymenotes (Westwood, 1839), Acridium (de Haan 1843), Choriphyllum (Thomas 1873; Bolívar 1887), has just recently found its home amongst the members of the genus Phyllotettix (Bruner 1910; Silva et al. 2019). This is the first leaf-like tetrigid, described just 7 years after Linnaeus’ 10th edition of Systema Naturae (Linnaeus 1758). There was a huge problem with the generic assignment and the authorship of Phyllotettix rhombeus. Even Silva et al. (2019: p4) incorrectly cited Linnaeus as the species’ author in one place of their manuscript. Our study is the first one ever to consistently use the correct generic combination and the correct authorship, that being Felton 1765, not Linnaeus, Backer, Baker, Fabricius, Westwood or Walker (see taxonomic and nomenclatural history under the species).
The Jamaican Colossal Jumping Leaf indeed is a “colossus”. Its pronotal length reaches almost 3 cm and its height reaches almost 2 cm, making it the unrivalled world’s largest Tetrigidae species known to date. The second largest is the Malagasy Holocerus devriesei, with a pronotum length of a little bit more than 2.5 cm (Skejo et al. 2020). This could be an example of island gigantism (e.g. Raia and Meiri (2006); Lokatis and Jeschke (2018)). Despite being the largest and the longest-known leaf-mimic pygmy grasshopper, nothing is known about the ecology or distribution of this extraordinary taxon from Jamaica. Except for its description, only one more specimen was reported (Westwood 1839; Hancock 1902a Plate I, fig. 2, as Choriphyllum westwoodi).
We assembled measurements by comparing those obtained from museum specimens with Westwood’s (1839) drawings. We deduced information about the size of Phyllotettix rhombeus indirectly, as it was not cited directly in Westwood’s (1839) text. Hymenotes triangularis and Choriphyllum sagrai were drawn in visibly different sizes, but next to each of them was the same scale of 8 lines (= 18 mm). We concluded that the lines represent the relevant measure and compared the scale of the aforementioned species with the scale drawn next to P. rhombeus, which we determined to represent about 13 lines (= about 29 mm).
<tp:taxon-name><tp:taxon-name-part taxon-name-part-type="tribe">Choriphyllini</tp:taxon-name-part></tp:taxon-name> taxonomically sorted a little better than before
All the members of the tribe Choriphyllini are reviewed and a new subgenus (Rhombotettix subgen. nov.), new species groups/complexes (Phyllotettix (P.) (compressus) sp. complex nov.; Choriphyllum (sagrai) sp. complex nov.) and a new combination (Phyllotettix (Rhombotettix) plagiatus comb. nov.) are proposed in order to try to reflect the evolutionary history of this interesting taxon, as observed from morphological similarity. The species complex was established in order to clearly point out that the species included in it share many morphological characteristics and have extremely small differences, so it is not clear whether they have separate evolutionary histories.
Choriphyllum sagrai is not a nomen dubium (Silva et al. 2019), as Serville’s (1838) description and drawings clearly match the species found in many localities in Cuba, some of them reported herewith. Choriphyllum sagrai was, however, hiding one secret, as the specimen identified some time ago by the first author as this species, deposited at the MNCN, was found to represent a separate species closely related to C. sagrai, C. wallaceum sp. nov., described in this study.
The newly-described species and the existence of Choriphyllum bahamense on the tiny and low island of Hummingbird Cay in the Bahamas imply that more Choriphyllum species are to be found in the future. The huge diversity of Phyllotettix in Jamaica, based on a few specimens only, provides even stronger evidence that we are still in the very beginning of understanding the Caribbean Pygmy Jumping Leaves.
Is the Phyllotettix (Phyllotettix) (compressus) complex only a single species or two or three closely related species? We can only speculate from four museum specimens, a drawing and a photograph of a living individual. Hence, at this moment, synonymisation or new species establishment would not bring any solution, but instead, introduce more chaos into an already loosely founded system. For Phyllotettix (Rhombotettix) plagiatus comb. nov. and P. (R.) rhombeus little can be said, as the holotypes, unfortunately, remain the only specimens from which information can be extracted.
The long history of this small tribe illustrates how mistakes accumulate when there is a lack of material which is badly handled as well. Previous authors did not all have the means to carefully examine the material or were unaware of its existence, leading to confusing synonymies (e.g. Hancock (1902a)). Silva et al. (2019) provided a good starting point for examining these tetrigids, but overlooked some important data, leading to muddying of the taxonomy in some places, most notably in the case of C. sagrai. Well-discussed taxonomic acts, especially when dealing with making a taxon a synonym or a nomen dubium, are an absolute must in order to avoid future errors.
Next steps in the Caribbean Pygmy Jumping Leaves research
A lot of the crucial information on the Caribbean pygmy jumping leaves is still lacking, despite the two-and-a-half-century-long research tradition (from Felton 1765 to Silva et al. 2019). This research tradition did not age well, so that data on the true species’ distribution remains almost entirely absent. Scientists can still deal only with imprecise locality data for some species, such as “Jamaica” for Phyllotettix (Rhombotettix) rhombeus and P. (R.) plagiatus (Felton 1765; Westwood 1839).
Citizen scientists in the Caribbean should be encouraged to collect observations of these grasshoppers and consequently, the citizen science platforms, such as iNaturalist, should be regularly monitored by scientists in order to establish and maintain a continuous research practice. Such practice is already proven to work (e.g. Mesaglio et al. (2021); Connors et al. (2022)).
The aim of future research should be collecting more specimens, so our hypotheses on the species and their positions may be tested. Museum collections should be investigated as well to see whether there are more undocumented species/specimens. Fieldwork in the Caribbean region is necessary. Only fresh samples may provide a predisposition for the next step, an evolutionary study by means of molecular phylogeny. By bringing these charismatic critters to public attention and making their identification easier, we hope to foster a wider interest in them.