Research report: Studies on Neotropical Pseudophyllinae : Integrative description of Dentotibium gen. nov., and of a toothed foretibia katydid ( Orthoptera : Tettigoniidae ) that sings from burrows in branches

An integrative taxonomic study of katydids in Boyacá, Colombia, describes a new genus and species, Dentotibium ramucantoris , combining morphology, natural-history observations, recordings of two captive males, passive acoustic monitoring and previously published DNA-barcode data. The short-winged species was found singing from burrows in branches and lianas in the Eastern Andes between 1,600 and 2,300 metres above sea level. The researchers studied specimens collected near Coper at 1,600 metres and in the 16-hectare Reserva Natural y Cascada Los Tucanes, a private reserve of sub-Andean and oak forest near Gachantivá at 2,100–2,300 metres.

The new taxon is a moderately robust, predominantly ocher katydid with black markings on the head and pronotum, black tegmina with yellow venation and greatly reduced wings. Males measured 21–30 millimetres in body length and females 34–36 millimetres. Morphological comparisons distinguished Dentotibium from superficially similar brachypterous genera, including Trichotettix , Nastonotus , Nannotettix and Natagaima .

Unlike Trichotettix , the new genus lacks dense hairs on the pronotum and legs, has ventral femoral spines and dorsal foretibial tubercles, and has one robust, downward-curving preapical spine on each male cercus. It differs from Nastonotus in lacking three black vertex stripes, a marked fronto-genal suture and a rugose face. Its male titillators are membranous rather than well sclerotized and peduncular.

The name Dentotibium refers to the teeth on the dorsal margins of the foretibiae, where each margin bears a row of four tubercles in the described species. The male stridulatory file contained 148–155 elongated, laterally flattened teeth. The species name ramucantoris combines Latin terms for branch and singer, referring to its habit of calling from burrows in branches and lianas.

DNA-barcode information previously published by Baena-Bejarano and colleagues was included for two paratypes, which shared the operational taxonomic unit and Barcode Index Number BOLD:AEI5327. In captive recordings, each calling syllable coincided with one complete opening and closing movement of the tegmina. For a male recorded at 13.7°C, syllable duration was 73.52 ± 6.80 milliseconds, syllable period was 485.60 ± 9.76 milliseconds and peak frequency was 20.46 ± 0.06 kilohertz; the −10-decibel bandwidth was 6.76 ± 0.28 kilohertz.

At 21.6°C, a second male produced syllables lasting 31.14 ± 2.60 milliseconds, with periods of 283.59 ± 8.39 milliseconds, peak frequencies of 20.36 ± 0.20 kilohertz and bandwidths of 3.97 ± 0.27 kilohertz. The recording made at 13.7°C contained three distinguishable syllable sections: an introductory section of three or four discrete pulses, a middle section containing overlapping pulse trains and a final section in which the amplitude faded and individual pulses could not be resolved. Pulse period did not differ significantly between the two recorded temperatures, although their standard-deviation ranges overlapped.

The authors said intraspecific variation may have masked a temperature effect and proposed that scraper speed might influence tooth contact and resonance, a hypothesis they described as untested. Passive monitoring at Reserva Natural y Cascada Los Tucanes supplied one-minute recordings every 30 minutes from 1 March 2020 to 22 January 2021, with gaps caused by COVID-19 restrictions. A spectrogram pattern-matching model evaluated 11,882 recordings and detected the species in 23%.

Manual annotation of 1,306 recordings indicated continuous activity from about 18:00 to 04:00, with a seasonal peak from October through April and fewer detections during the June–August dry season. An earlier analysis cited by the study found a negative association between acoustic activity and lunar phase. Field observations showed males singing from thin trunks, branches and hard vines, often exposing the front half of their bodies at burrow entrances.

Burrows occurred in the understory or midstory, sometimes near the ground, and extended from about 20 centimetres to more than 35 centimetres deep. Resident males emerged, raised their forelegs, opened their mandibles and produced a defensive call when another male approached, although that call was not recorded. Copulation occurred inside the burrow with the male and female facing opposite directions.

Researchers also observed bats flying toward burrows without catching a katydid. Field recordings also contained substantial background noise, limiting comparisons among individuals, while gaps interrupted the passive-monitoring schedule. The response of the katydids to bats and possible echolocation was not tested, so predator-related explanations were presented as hypotheses rather than established mechanisms.

The study nevertheless provides a combined morphological, acoustic, behavioral and genetic description intended as a foundation for systematics, evolution and monitoring research on the new taxon.

Subject of Research: Integrative description of a new branch-burrow katydid genus and species from the Colombian Eastern Andes

Article Title: Studies on Neotropical Pseudophyllinae : Integrative description of Dentotibium gen. nov., and of a toothed foretibia katydid ( Orthoptera : Tettigoniidae ) that sings from burrows in branches

Article References: Cadena-Castañeda, O. J., Gomez-Morales, D. A., Acevedo-Charry, O., & Benavides-López, J. L. (2024). Studies on Neotropical Pseudophyllinae: Integrative description of Dentotibium gen. nov., and of a toothed foretibia katydid (Orthoptera: Tettigoniidae) that sings from burrows in branches. Journal of Orthoptera Research, 33(2), 267-280. https://doi.org/10.3897/jor.33.116137

Image Credits: AI Generated

DOI: 10.3897/jor.33.116137

Keywords: Dentotibium ramucantoris, katydid, integrative taxonomy, bioacoustics, calling song, morphology, DNA barcoding, passive acoustic monitoring, Colombian Andes, Studies, Neotropical, Pseudophyllinae