Dentotibium ramucantoris Cadena-Castañeda & Gomez-Morales, 2024

Cadena-Castañeda, Oscar J., Gomez-Morales, Diego A., Acevedo-Charry, Orlando & Benavides-López, Jose Luis, 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), pp. 267-280 : 267-280

Dentotibium ramucantoris Cadena-Castañeda & Gomez-Morales sp. nov.

Etymology. —

The species name derives from the conjunction of the Latin “ ramus ” (“ branch ”) and “ cantor ” (“ singer ”), referencing how this new species sings from inside the burrows of branches and lianas. The specific epithet is substantive and independent of grammatical gender.

Type material. —

Holotype — COLOMBIA • ♂; Boyacá, Coper, Vereda Turtur, Sector San Ignacio ; 1600 m.; 5 ° 25 ' 32.03 " N, 74 ° 0 ' 15.24 " W.; October 2019.: O. J. Cadena-Castañeda leg.; CAUD . Paratypes — COLOMBIA • 2 ♂, 2 ♀; same data as holotype; CAUD • 2 ♂; Boyacá, Gachantiva, Vereda la Caja, Reserva Natural y Cascada Los Tucanes , 2100–2300 m; 5 ° 47 ' 21.336 " N, 73 ° 33 ' 1.584 " W; September 2020; Diego A. Gomez-Morales leg ( IAVH-E 218714 ); September 2020; Diego A. Gomez-Morales ( IAvH-E 218391 ); CAUD • 1 ♂; Boyacá, Gachantiva, Vereda la Caja, Reserva Natural y Cascada Los Tucanes ; 2100–2300 m; 5 ° 47 ' 21.336 " N, 73 ° 33 ' 1.584 " W; 23 January 2021; Diego A. Gomez-Morales leg.; CAUD .

Description. —

Male. In addition to the characters mentioned above: Coloration. Ochre-colored head, thorax, and legs; light brown abdomen (Fig. 1). Head with a black stripe from inferior border of antennal sockets, surrounding eye sockets, and reconnecting dorsally, covering the fastigium (Fig. 1 C); eyes light purple; mandibles dark reddish brown with black internal borders (Fig. 1 C, D); pronotum with black delineated sulcus on anterior and posterior margins (Fig. 1 B, D); femora apex, foretibia dorsal margin, and foretibia base blurred in reddish brown; tegmina black and with yellow venation (Fig. 2 A – D), hind wings translucid; tenth tergite with two ovoid light brown spots, one on each side (Fig. 2 G). Head. Big, pedicel with a basal tubercle on the ventral margin; fastigium small and elevated (Fig. 1 C), triangular in dorsal view (Fig. 1 B), with small and rounded ocelli on each side; frontal ocelli inconspicuous (Fig. 1 C); first, second, and third segments of maxillary palpi of similar size; fifth segment longer and dilatates toward the apex (Fig. 1 D). Thorax. Anterior margin of pronotum rounded, posterior margin straight (Fig. 1 B); pronotal disc slightly wavy in lateral view, rising between pro- and mesozone, descending at mesozonal sulcus, and rising again toward the posterior margin (Fig. 1 D). Wings. Tegmina lanceolate, slimmed down toward the apex (Fig. 2 A – D) and covering the third and fourth abdominal segments (Fig. 1 A, B); tegminal M and R veins never converging, and Rs vein originateing near the tegminal apex (Fig. 2 A); stridulatory file (= A 1) almost straight, with 148–155 elongated and laterally flattened teeth (Fig. 2 E), mirror of the left tegmina ovoid-shaped and two times as long as wide (Fig. 2 C, D); tegminal A 1 vein ventrally shaped as a fold with small, challenging-to-see denticulations (Fig. 1 C). Legs. Forefemur ventrally armed with only a tiny spine on the inner margin close to the apex; foretibia armed dorsally with four tubercles on each dorsal margin; ventrally armed with seven spines on inner margin and two to four spines on outer margin. Mid-femur with two spines on the ventral-outer margin (Fig. 1 D); mid tibia slightly dilated dorsally on first half, ventrally armed with five outer spines and two inner ones. Hind femur with three to seven spines on the outer ventral margin (Fig. 1 A); hind tibia dorsally with four spine-like tubercles on the outer margin, and inner margin armed with nine or ten spines (Fig. 1 B); internal genicular lobes of fore and middle femora armed, the rest without spines. Abdomen. Posterior margin of the tenth tergite straight (Fig. 2 F, G); epiproct triangular, with rounded posterior border, lateral margins sub-elevate (Fig. 2 F). Cerci tumescent, with a rounded apex and a preapical hook-shaped ventral spine curved downwards and toward the inner apex, strongly sclerotized and with a softly acuminated apex (Fig. 2 F). Paraprocts wide, ovoid, unmodified; the subgenital plate quadrangular and almost as wide as long, with a pair of cylindrical styli in the distal margin and a moderately deep U-shaped notch between them (Fig. 2 H). Male genitalia. Posterior margin of lw. vl. wavy; up. vl reduced in dorsal view, composed of two folds (one at each side) of medium length and grooved surface; dl short, with rounded posterior and lateral margins, without modifications or microstructures (Fig. 3 A); ti softly golden colored, located in the posterior ventral surface of the genitalia, with no conspicuous modifications and with sparse holes along the surface (Fig. 3 B, C); ejd tubular, progressively thinner toward inside the phallus, and with golden sparse microstructures on its medial region (Fig. 3 A, B); ejd ending in the vdl, differentiated from the previously mentioned membranes (Fig. 3 A) and looking like channeled conduct from axial vie; ejv rounded, middle-sized, and connecting with inner ejd of genital membranes (Fig. 3 A, B).

Female. Similar to males in shape but notoriously larger; similar in color but with darker tones (Figs 4, 5). Tegmina covering up to the area between the fourth and fifth abdominal segments (Fig. 4 A, B), epiproct similar to male’s; conical and short cerci (Fig. 5 D); ovipositor slightly curved upwards, dorsally wavy, without sawed, but ventrally with little saws over the last distal third, acuminate apex (Fig. 5 E); ninth abdominal sternite quadrangular, with two inverted ear-shaped small prolongations over each end of the posterior margin and in between two lobes, covering the subgenital plate, the base with a depression, distal edge rounded and curving toward the external side and dorsal edge rounded and softly curving upwards (Fig. 5 F, G); subgenital plate with a notch in the posterior edge, with every distal edge ending at an acute angle (Fig. 5 G).

Distribution. —

Mid and highlands of Boyacá, Colombia, between 1600 and 2300 m above sea level.

Variation. —

The main variation present in the examined specimens is size: the ones from the midlands (Coper) are larger, having greater measurements than those from the highlands (Gachantiva). Midland females have black coloration in most of the medium and fore tibiae, while highland females’ foretibiae are completely ochre.

Measurements. —

(mm). Male / Female: LB: 21–30 / 34 – 36, Pr: 5–6 / 6 – 6.5, Teg: 8.5–9.5 / 16 – 17, HF: 10–11 / 15 – 16, HT: 9.5–10.5 / 15 – 15.5, SP: 2–3 / 2, Ov: 15–17.

DNA barcoding. —

Baena-Bejarano et al. (2023) published the DNA barcoding sequence (Fig. 7) for the mitochondrial cytochrome c oxidase subunit I (COI) gene, (COI - 5 P) of the two paratypes here described under the same Operational Taxonomic Unit (OTU) and Barcode Index Number (BIN): BOLD: AEI 5327 on the Barcode of Life Data System ( Ratnasingham and Hebert 2007) [dx. doi. org / 10.5883/BOLD: AEI 5327].

Bioacoustics. —

The calling song of D. ramucantoris sp. nov. consists of discrete syllables with a constant period of 485.60 ± 9.76 ms, duration of 73.52 ± 6.80 ms, and peak frequency of 20.46 ± 0.06 kHz (specimen B; Table 3 ) at 13.7 ° C and a 283.59 ± 8.39 ms period, 31.14 ± 2.60 ms and peak frequency of 20.36 ± 0.20 kHz at 21.6 ° C (specimen A; Table 5 , Fig. 6). Each syllable corresponds to a complete opening and closing phase of the tegmina, as observed while recording the individuals. The syllable bandwidth decreases with increasing temperature, being 6.76 ± 0.28 kHz at 13.7 ° C and 3.97 ± 0.27 kHz at 21.6 ° C.

At the lower temperature (13.7 ° C) for specimen B recorded from 0.50 m, the syllable shows three differentiable sections (Table 2 ): the introductory section with three to four discrete pulses (Fig. 8 E) of 0.96 ± 0.14 ms duration and a period of 3.27 ± 0.64 ms, the middle section with 1.54 ± 0.39 ms duration and 2.95 ± 0.50 period (Table 1 ) formed by complex wave pulses that seems to be the overlap of two simultaneous pulse trains (for which we measured the higher-amplitude pulse train), and a final section of fading out amplitude with no distinguishable pulses of 16.07 ± 3.14 length (Table 1 , Figs 6 D, 8 D).

For specimen A recorded at 21.6 ° C from 1.5 m, the syllable is made up of discrete pulses, of 0.71 ± 0.10 ms duration and with a 3.18 ± 0.34 ms period (Table 4 ; Fig. 8 B). It also has an overlapping section, although the lower-amplitude pulse train is much more subtle (Fig. 8 A).

The relationship between the overlapping pulse trains, temperature, and intraspecific variation requires further exploration. The syllable section units here described, as well as the - 10 dB bandwidth lower limit and - 10 dB bandwidth upper limit, might also be of importance to measuring intra- and interspecific variation.

Natural history. —

Copulation behavior in D. ramucantoris sp. nov. occurs with males’ and females’ heads facing opposite directions usually inside the burrow in the lianas where they live, as was observed when we sliced the branches in two. The female presents the folds in the last abdominal sternite and subgenital plate (Fig. 5 F, G), possibly to allow more efficient coupling. The territorial behavior of D. ramucantoris sp. nov. males is as follows: When a male gets closer to an occupied burrow, the dweller comes outside and raises their forelegs while opening their mandibles and emitting a defensive call. Unfortunately, we were unable to record the defensive call, and we did not observe any tremulatory or crepitating behavior.

Males were seen singing from burrows on thin trunks, branches, or hard vines. Burrows were mostly located in the understory – midstory, but some were near the ground. The males were seen positioning the capital half of their body outside the entrance to sing [10.6084/m9.figshare.23257832], but they were also singing from inside after being disturbed. The burrow depth of other males’ was variable, from ~ 20 cm to more than 35 cm. Future studies should seek a deeper understanding of how the burrows are made, and the remarkable natural history and ecological interactions of this new species.

Diel and annual singing schedule. —

Based on the manual annotation of 1,306 recordings between March and May of 2020 from passive acoustic monitoring ( Gomez-Morales and Acevedo-Charry 2022) complemented with the pattern matching model, males showed continuous acoustic activity from around 18: 00 to 04: 00 (Fig. 7), decreasing their activity before sunrise and ceasing acoustic activity during the day. Its calling song is conspicuous in the audible spectrum, can be heard from relatively long distances, and is easily distinguished. Gomez-Morales and Acevedo-Charry (2022) found a negative relationship between the acoustic activity of Dentotibium ramucantoris sp. nov. and the moonlight phase, a key environmental driver of its activity. We additionally identified the seasonal calling song patterns, finding a prominent peak of activity from October (week 40) to April (week 17) and then a decrease in activity mid-year (June – August; weeks 24–35) (Fig. 7), which matches the dry season of the study site ( Secretaría de Salud de Boyacá 2013).