The scale of the confusion the authors faced is remarkable. The history of these insects stretches back more than two and a half centuries, to a time when the boundaries between cicadas, leafhoppers and grasshoppers were far from settled. Phyllotettix rhombeus, the largest known member of the entire grasshopper family Tetrigidae, was first described in 1765 as a cicada, Cicada rhombea, just seven years after Linnaeus’ tenth edition of Systema Naturae. Over the following decades it was shuffled between the genera Membracis, Hymenotes, Acridium and Choriphyllum before finally landing in Phyllotettix. Even recent treatments got the authorship wrong, with a 2019 review incorrectly citing Linnaeus as the species’ author in one place. The new study is, according to its authors, the first to consistently use the correct combination and the correct author, Felton 1765.

That long history of misassignment illustrates a broader problem the authors highlight: when material is scarce and badly handled, mistakes accumulate. Previous researchers did not always have the means to examine specimens carefully, or were unaware that relevant material existed, leading to confusing synonymies. The 2019 review that established the tribe Choriphyllini provided a good starting point, the authors write, but overlooked some important data, most notably in the case of the Cuban species Choriphyllum sagrai.

Choriphyllum sagrai, described by Serville in 1838 and the type species of the genus Choriphyllum, had been declared a nomen dubium, a name of doubtful application, in the 2019 review because its type specimen could not be found. The new study overturns that decision. Serville’s original description and drawings, the authors argue, clearly match a species that has since been found and photographed at several localities in Cuba, so nothing about the species’ identity is actually doubtful. The type specimen is likely deposited at the Muséum national d’Histoire naturelle in Paris but has not yet been located; the holotype is known from Serville’s 1838 drawing, which the authors state undoubtedly shows the species found in Cuba. New records reported in the study come from Pinar del Río and Artemisa provinces, including specimens collected in 2015 in Viñales Municipality and historical museum material from sites such as Sierra Rangel, Sierra del Rosario and Aspiro, some gathered from leaf litter in a coffee plantation as far back as 1930.

That re-examination of old material also yielded a surprise. A specimen at the Museo Nacional de Ciencias Naturales in Madrid, previously identified as Choriphyllum sagrai, turned out on closer inspection to represent a separate, closely related species. It is now described as Choriphyllum wallaceum, a new species named after Alfred Russel Wallace, the father of biogeography, in celebration of the 200th anniversary of his birth on 8 January 1823. The holotype is a male with no specified collection locality in Cuba, bearing labels that reveal its own tangled history: one handwritten by Bolívar identifying it as an unpublished species he called Choriphyllum seoanei, another noting that the species was never published, and a later determination label reading Choriphyllum cf. sagrai. The new species differs from C. sagrai in the shape of its pronotal crest, the modified saddle-like structure on the back that gives these insects their leaf-like silhouette: in C. wallaceum the highest region is shaped as a slanted plateau and more angular, whereas in C. sagrai it is rounded, and the legs of C. wallaceum are generally rougher, with tubercles on the femora.

The genus Choriphyllum now contains four species. Besides C. sagrai and the new C. wallaceum, both endemic to Cuba, there are C. saussurei, described by Bolívar in 1887 and known from west-central Cuba and Isla de Pinos, where Gundlach recorded it dwelling under leaf litter in the mountains, and C. bahamense, known only from Hummingbird Cay Island in the Bahamas. The study also corrects a grammatical error, changing C. bahamensis to C. bahamense to match the neuter gender of the genus. C. bahamense has not been recorded since its description in 1999, and the authors note that, given its very small area of occupancy and its affinity for rainforest habitat, the species might be endangered, though this has yet to be assessed through fieldwork.

The second genus, Phyllotettix, is endemic to Jamaica and holds the tribe’s most spectacular member. Phyllotettix rhombeus, the Jamaican Colossal Jumping Leaf, has a pronotum, the enlarged shield extending backwards over the body, that reaches almost three centimetres in length and almost two centimetres in height, making it the unrivalled largest Tetrigidae species known to date. The second largest is the Malagasy Holocerus devriesei, with a pronotum a little over 2.5 centimetres long. The authors suggest this could be an example of island gigantism, though they stress that almost nothing is known about the ecology or distribution of this extraordinary insect. Apart from its original description, only one further specimen had ever been reported, by Westwood in 1839 and Hancock in 1902.

Reconstructing the size of that historical specimen required some detective work. Because Westwood’s 1839 text did not directly cite the dimensions of the P. rhombeus drawing, the authors deduced them indirectly by comparing the scale bars accompanying drawings of other species. Hymenotes triangularis and Choriphyllum sagrai were drawn at visibly different sizes but each carried the same scale of eight lines, equivalent to 18 millimetres, allowing the authors to determine that the scale next to the P. rhombeus drawing represented about 13 lines, or roughly 29 millimetres. Comparative measurements across the tribe, compiled in the study, show the pronotal length of the P. rhombeus holotype at 28.8 millimetres, far exceeding any other Choriphyllini specimen measured.

The review also untangles a long-standing nomenclatural knot in Jamaica. Choriphyllum westwoodi, a name established by Hancock in 1902, is shown to be a synonym of Phyllotettix rhombeus, not of P. compressus as previously thought. Although Hancock had intended the name as a replacement for Acrydium compressum, the type specimen on which it was based actually belongs to P. rhombeus, as demonstrated by overlapping Felton’s and Westwood’s historical drawings, which are almost identical. In addition, Choriphyllum plagiatum, described by Walker in 1871, is transferred to Phyllotettix as a new combination, and a new subgenus, Rhombotettix, is established to contain P. plagiatus and P. rhombeus, distinguished by a pronotal crest that is obliquely projected and undulated in side view and a pronotum that reaches behind the hind knees. The nominotypical subgenus Phyllotettix contains P. compressus and P. foliatus, two very similar Jamaican species that the authors place in a new species complex, acknowledging that they may represent subspecies of a single species, or that the complex may include undescribed species. A parallel complex, Choriphyllum (sagrai), groups C. sagrai and C. wallaceum.

The authors are candid about the limits of what four museum specimens, a drawing and a single photograph of a living individual can resolve. For the P. compressus complex, they write that synonymising species or describing new ones at this moment would introduce more chaos into an already loosely founded system rather than bring any solution. For P. plagiatus and P. rhombeus, little can be said because the holotypes remain the only specimens from which information can be extracted. Biogeographic data for the whole tribe is scarce: the study’s distribution map covers six species, but the distribution of three of them is missing entirely because no localities are known. Even P. rhombeus and P. plagiatus are recorded only as being from Jamaica, without any precise locality.

One bright spot comes from citizen science. A living individual of P. compressus photographed in the Blue Mountains northeast of Kingston and uploaded to iNaturalist in May 2022 provided the first confirmed locality for a species that until recently was known from no specified site at all. P. foliatus has also been reported from the same mountain range, from specimens collected at Hardwar Gap in 1925, where the collector noted the insects feeding on lichens on tree trunks at night. The authors call for Caribbean citizen scientists to be encouraged to document these grasshoppers and for platforms such as iNaturalist to be regularly monitored, a practice they note has already proven effective elsewhere. They argue that future progress depends on collecting more specimens to test current hypotheses, investigating museum collections for undocumented material, and conducting fieldwork in the Caribbean, since only fresh samples could enable the next step, an evolutionary study using molecular phylogeny. The existence of the newly described C. wallaceum and of C. bahamense on the tiny island of Hummingbird Cay, together with the diversity of Phyllotettix in Jamaica known from just a handful of specimens, suggests, the authors conclude, that we are still at the very beginning of understanding the Caribbean pygmy jumping leaves.

Subject of Research: Taxonomic revision of the leaf-like Caribbean pygmy grasshopper tribe Choriphyllini

Article Title: Caribbean pygmy jumping leaves ( Tetrigidae , Cladonotinae , Choriphyllini )

Article References: Skejo, J., Yong, S., Bogić, D., & Kasalo, N. (2023). Caribbean pygmy jumping leaves (Tetrigidae, Cladonotinae, Choriphyllini). Deutsche Entomologische Zeitschrift, 70(1), 129-141. https://doi.org/10.3897/dez.70.98982

Image Credits: AI Generated

DOI: 10.3897/dez.70.98982

Keywords: Tetrigidae, Cladonotinae, Choriphyllini, pygmy grasshoppers, taxonomy, Caribbean, Cuba, Jamaica, new species, Phyllotettix, Choriphyllum, biogeography