Research Article |
Corresponding author: Pablo Valero ( pvr230286@gmail.com ) Academic editor: Sven Bradler
© 2024 Oskar V. Conle, Pablo Valero, Frank H. Hennemann.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Conle OV, Valero P, Hennemann FH (2024) A new Trychopeplus species (Phasmatodea, Diapheromerinae, Cladomorformia) discovered from Ecuador’s enigmatic Chocó ecoregion. ZooKeys 1217: 309-326. https://doi.org/10.3897/zookeys.1217.130397
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This study presents a description of a new stick insect species belonging to the genus Trychopeplus Shelford, 1909, discovered by the authors in the Chocó ecoregion of northwestern Ecuador. Trychopeplus mashpiensis sp. nov. is described and illustrated based on males, females, and eggs. The distinctive features of this new species, such as its unique body ornamentation and the morphology of its egg structure without fringes, clearly differentiate it from other known species within the genus. Photographs of the new species are provided, along with an updated key and distribution map for all Trychopeplus species. These findings enhance our understanding of the genus’s diversity.
Identification key, Insecta, stick insects, taxonomy, morphology
Trychopeplus Shelford, 1909, is a genus of Neotropical stick insects (order Phasmida Leach, 1815) known for its remarkable morphological adaptations that allow it to blend almost perfectly with the epiphytic mosses in its habitat. These adaptations make Trychopeplus one of the most cryptic stick insect genera (
The genus was described by Shelford in 1909 to distinguish Neotropical species from Pericentrus Redtenbacher, 1908, based on morphological differences and distinct geographic distributions compared to the type species Pericentrus moewisi Redtenbacher, 1908. The known distribution of Pericentrus is confined to East and South Asia, while Trychopeplus is endemic to the Neotropics (
Traditional taxonomic revisions by
Until now, the only eggs described from the genus were those of the type species Trychopeplus laciniatus (Westwood, 1874), which were characterised by being entirely covered with long fringes, a trait previously considered a potential autapomorphy of the genus (
This study aims to describe a new species, Trychopeplus mashpiensis sp. nov., based on specimens collected from the Chocó forests in northwestern Ecuador. Through a comprehensive morphological analysis of males, females, and eggs, distinctive features are described and illustrated, which not only distinguish this new species from its congeners but also provide crucial insights into intrageneric variability. Furthermore, an updated key to all known Trychopeplus species is presented, along with a distribution map for the genus.
The material used in this study was collected through nocturnal direct sampling on trails near Mashpi Lodge, located in the parish of Pacto, northwest of the Ecuadorian province of Pichincha. Samplings took place from 1–4 October, 2023, under the collection permit MAATE–ARSFC–2023–3348.
The adult females collected were kept in a terrarium for several days to lay eggs. Euthanasia was performed by immersing the specimens in 96% ethanol for a few minutes. Both adults and eggs were stored dry, with adult specimens pinned. Insects and eggs were examined using a stereoscope (Zeiss Stemi SV6). Measurements were taken with a digital caliper at a precision of 0.1 mm. All eggs examined were fully developed and already laid. The terminology used for the descriptions of egg structures follows that of
Diapheromeridae
Diapheromerinae Kirby, 1904
Cladomorformia
Pericentrus multilobatus Redtenbacher, 1908: 352 (= Ceroys laciniatus Westwood, 1874: 174), by original monotypy.
Trychopeplus Brunner v. Wattenwyl, in litt.
Ceroys Westwood, 1874: 174, pl. 32: 4 (♀).
Parobrimus Kirby, 1904: 344.
Pericentrus Redtenbacher, 1908: 352 (in part). Shelford, 1909: 356.
Trichopeplus
Trychopeplus laciniatus (Westwood, 1874: 174, pl. 32: 4) [Nicaragua, Costa Rica, Panama]
= Pericentrus multilobatus Redtenbacher, 1908: 352
Trychopeplus spinosolobatus (Redtenbacher, 1908: 353) [Venezuela]
= Pericentrus appendiculatus Redtenbacher, 1908: 353.
Trychopeplus thaumasius Hebard, 1924: 148, pl. 6: 8 & 9 [Colombia, Ecuador]
= Trychopeplus ortho-lamellatus Campos, 1926: 15 & pl.
Trychopeplus mashpiensis Conle, Valero & Hennemann sp. nov. [Ecuador]
Holotype
• ♂; Ecuador: Prov. Pichincha, Parroquia de Pacto, Mashpi Lodge; 0°09'58.0"N, 78°52'38.4"W; 800–1000 m; leg. Cisneros, Conle, Valero & Hennemann 1–4.10.2023. [
T. mashpiensis sp. nov. is clearly distinguishable from T. laciniatus and T. thaumasius by the shape of its ornamentation, which is spiny in the new species and consists of irregular foliar lobes in T. laciniatus and T. thaumasius. Additionally, the distribution of T. laciniatus appears to be restricted to Central America (Fig.
The female of the new species is similar to T. spinosolobatus, of which the male and egg are unknown. However, they can be easily differentiated by the shape of the spines, the ornamentation of the femora, and the length of the subgenital plate. In T. mashpiensis sp. nov., the tips of the body spines are acute, while in T. spinosolobatus they are clearly rounded. The femoral ornamentation of T. mashpiensis sp. nov. consists only of two pairs of foliar lobes (Figs
Female of Trychopeplus mashpiensis sp. nov. a habitus in lateral view b head and thorax in dorsolateral view c head, pro- and mesothorax in dorsal view d mesofemora in dorsal view e end of the abdomen in dorsal view f end of the abdomen in lateral view g end of the abdomen in ventral view.
Male of Trychopeplus mashpiensis sp. nov. a habitus in lateral view b head and thorax in dorsolateral view c head, pro- and mesothorax in dorsal view d mesofemora in dorsal view e end of the abdomen in dorsal view f end of the abdomen in lateral view g end of the abdomen in ventral view h detail of the vomer.
The colouration is described mostly from photographs of live specimens. Table
Measurements (mm) of Trychopeplus mashpiensis sp. nov. HT = holotype; PT = paratype.
♂, HT [ |
♂♂, PT [ |
♀♀, PT [ |
♂♂, PT [ |
♀♀, PT [ |
|
---|---|---|---|---|---|
Body (incl. subgen. pl.): | – | – | 81.5–87.4 | – | 83.6–85.7 |
Body: | 73.3 | 72.3–74.3 | 79.6–85.6 | 72.6–73.9 | 82.1–83.0 |
Pronotum: | 2.5 | 2.7–3.1 | 3.7–4.5 | 2.7–2.8 | 4.1–4.3 |
Mesonotum: | 14.1 | 14.5–14.7 | 18.0–19.4 | 14.1–14.3 | 17.7–19.0 |
Metanotum: | 4.1 | 3.6–4.3 | 5.6–6.2 | 3.0–4.4 | 6.2–7.4 |
Median segment: | 10.5 | 10.7–10.9 | 6.4–7.1 | 9.4–10.3 | 4.4–6.4 |
Tegmina: | 5.8 | 6.3–6.5 | – | 5.6–5.7 | – |
Alae: | 35.7 | 34.5–37.7 | – | 34.9–36.8 | – |
Profemora: | 27.6 | 27.2–28.0 | 23.9–26.2 | 26.4–28.2 | 24.6–26.3 |
Mesofemora: | 21.3 | 22.1–22.4 | 17.8–18.8 | 22.3–23.0 | 19.1–20.6 |
Metafemora: | 25.2 | 26.1–26.9 | 22.1–22.3 | 26.5–27.6 | 23.3–24.5 |
Protibiae: | 30.5 | 30.9–31.0 | 25.4–28.0 | 30.6–31.1 | 26.1–29.2 |
Mesotibiae: | 22.3 | 22.6–22.9 | 19.7–21.3 | 22.6–22.8 | 19.9–23.1 |
Metatibiae: | 27.8 | 28.3–28.9 | 26.0–28.8 | 28.9–29.0 | 26.3–32.0 |
Antennae: | 74.1 | 74.5–75.2 | 23.8–61.1 | 74.2–75.3 | 62.1–70.6 |
♀♀ (Figs
Head. The head is ovoid, with the occiput strongly convex, approximately 1.4 times longer than wide. The vertex features two dorsolateral formations of spines or conical protuberances, arranged more or less in line, two of which are prominently larger and slightly pointing towards the posterior. Additionally, irregular and much smaller conical protuberances are present between these formations, as well as on the genae. The eyes are medium-sized, nearly circular in shape, projecting almost hemispherically, and their diameter is approximately twice the length of the genae. The antennae are filiform and reach the posterior margin of abdominal segment V. The scape is dorsoventrally compressed, with the outer lateral margin gently concave and approximately 2.1 times longer than wide. The pedicel is round in cross-section and somewhat constricted apically.
Thorax. The entire thorax is densely covered with spine-like protuberances, varying in size and generally exhibiting a degree of bilateral symmetry. The pronotum is approximately 0.75 times the length of the head and 0.9 times its width, with a basically rectangular shape and a slight premedial narrowing. The anterior margin is somewhat elevated. The transverse median sulcus is moderately distinct, curved, and nearly expanding across the entire width of the segment. It features several dorsal spines, arranged approximately parallel to each other; the first pair of spines are simple and small, located just before the transverse median sulcus; the second pair is situated near the posterior margin of the pronotum, larger in size and appearing paired, almost as if forming a single bifurcated structure. The mesothorax is approximately 4.3 times longer than the prothorax and of uniform diameter except for a slight anterior narrowing. Among the spines of the mesonotum, the most prominent are located approximately at the distance of the first and second quarters of its total length. The metanotum is approximately one-third the length of the mesonotum. The posterior margins of the meso- and metanotum exhibit two dorsal spines each, parallel-sided and of medium size, slightly directed backwards.
Abdomen. The abdomen (excluding the subgenital plate) is approximately the same length as the combination of the head and thorax (including the median segment). The median segment is roughly the same size as the metanotum and is more or less quadrangular. Segments II–IX feature prominent dorsoventrally flattened lobes, with rounded margins on the posterior sides of each segment. These lobes gradually increase in size from segment II to VI, and then gradually decrease until segment IX. Segment II is slightly shorter than the median segment and slightly longer than wide. Segments II–V have approximately the same length and width, while from VI to IX, they gradually decrease in length and width. Sternites II–VII exhibit small blunt spines and a medial protuberance on the posterior margin of each segment, covered by small setae. The preopercular organ is barely distinguishable and consists simply of a small, wart-like swelling near the posterior margin of sternite VII; the entire area is dark reddish-brown. The anal segment is slightly longer than tergum IX and has a generally rounded outline, except for a small posterior medial incision and two triangular lateral projections near the base. The epiproct is very small and almost completely hidden beneath the anal segment. The cerci are of similar length to the anal segment, thin, and circular in cross-section; extending clearly beyond the posterior margin of the anal segment. The gonapophyses are moderately enlarged, keeled, and almost reaching the base of the cerci. Gonapophysis VIII is relatively long and slightly curved upwards, reaching approximately the posterior margin of the anal segment or even slightly surpassing it, but never reaching the apex of the subgenital plate. The subgenital plate is shovel-shaped, slightly longitudinally keeled, and projecting approximately 20% of its total length over the apex of the anal segment; the lateral margins are undulated and the apex is slightly curved downwards.
Legs. All legs are long and slender. Both femora and tibiae are trapezoidal in cross-section, with the two dorsal carinae closely spaced. All femora are strongly curved. Additionally, the profemora are also strongly curved at the base to accommodate the head when aligned in line with the body. The meso- and metafemora feature two pairs of foliaceous lobes on the ventral carinae, one on the outer ventral carina and another on the inner, with rounded edges. The first pair is located approximately at one-third from the base, consisting of semicircular lobes. The second pair is positioned at the posterior end of the profemora, and they are at least twice as long as they are wide. In the profemora, the lobes are similarly arranged but only present on the outer ventral carina. All femora are longer than the mesothorax. All tibiae are slender, more or less straight, slightly longer than the corresponding femur, and lack ornamentation. The basitarsi are slightly shorter than the combined remaining tarsomeres and also lack ornamentation.
♂♂ (Figs
The general colouration is similar to that of the female, though usually with less green. The tegmina and the costal area of the alae follow the same colouration pattern as the rest of the body, while the anal area of the wings is uniformly translucent ochre. The cerci are light green.
Head. The head is very similar to that of the female, but with smaller ornamentation. However, the eyes are proportionally larger, with a diameter approximately 1.4 times the length of the genae. Ocelli absent. The antennae, although similar to those of the female, are proportionally longer, reaching and even slightly exceeding the total body length.
Thorax. The thorax ornamentation is very similar to that of the female in terms of the number and position of spines, but these are much smaller, with the smallest considered as small protuberances rather than spines. The pronotum is approximately 0.75 times the length and width of the head, similar in shape to that of the female but with small protuberances instead of spines. The mesothorax is approximately 4.6 times longer than the pronotum and uniformly wide throughout its length. As in the female, the most prominent spines on the mesonotum are arranged in the first and second quarters of its total length; however, they are smaller than in the female, and the remaining spines appear as small protuberances. The metanotum is approximately one-third the length of the mesonotum and, unlike the female, does not have spines on the posterior margins. The tegmina are simple, with a slight elevation at the base of the wings to accommodate them; they are approximately 3.2 times longer than wide and cover a little more than one-third of the total length of the metathorax. The wings are approximately twice as long as they are wide and reach the abdominal segment VI.
Abdomen. The abdomen is approximately the same length as the combined head and thorax (including the median segment). The median segment is 2.7 times longer than the metanotum. As in the female, segments II–IX have flattened lateral lobes near the posterior margin of each segment, but in the males, these are very small and uniformly sized across all segments. Abdominal segment II is approximately 0.5 times the length of the median segment and about three times longer than wide. Segments II–VII are all the same width, while VIII and IX are slightly wider. Segment III is the same length as segment II. From segment IV onwards, the length of each segment gradually decreases slightly. The median segment and tergites II–IX have a smooth surface without ornamentation.
Sternites II–VII have small blunt spines and a medial protuberance on the posterior margin of each segment. The anal segment is approximately 0.6 times the length of tergite IX and, as in the female, has a generally rounded outline, except for a small posterior medial incision and two triangular lateral projections near the base. The cerci are approximately 1.5 times longer than the anal segment, clearly extending beyond its posterior margin; they are slender and circular in cross-section. The vomer is shaped like a sharp spine and dorsoventrally flattened, with the basal half broadly widened. The poculum is shaped like an elongated scoop, with a small basal protuberance in the centre. In ventral view, it is asymmetrical, as the right outer margin presents a small expansion. The posterior margin is rounded and reaches halfway up the anal segment.
Legs. The legs have similar morphology and ornamentation to those of the females, although they are longer, slender, and with less curved femora. All femora are longer than the combined head, pro-, and mesothorax. All tibiae are thin, more or less straight, slightly longer than the corresponding femur, and lack ornamentation. The basitarsi are slightly longer than the remaining tarsomeres combined and also lack ornamentation.
Eggs
(Fig.
Length including operculum 3.6–4.2, length 2.9–3.4, height 2.5–2.8, width 2.2–2.4, length of micropylar plate 1.9–2.1.
So far, the species is known only from the type locality, in the northwest of Pichincha Province, Ecuador.
The epithet mashpiensis refers to the Mashpi Reserve, where the species was discovered, in appreciation for the excellent treatment received from the lodge staff and the scientific team, as well as their significant conservation efforts.
Note. The males of T. spinosolobatus and T. thaumasius remain undescribed.
♀♀ && ♂♂
1 | Prominent head and mesonotum ornamentation in the form of simple spines; mesofemora lobes simple with rounded margins | 2 |
– | Prominent head and mesonotum ornamentation in the form of foliate lobes or branched spines; at least the medial pair of mesofemora lobes are compound and have irregular margins | 3 |
2 | Subgenital plate 1.6× longer than combined tergites VIII–X; femora with four pairs of rounded foliate lobes, one at the apex and the rest in the first, second, and third quarter of the corresponding femur length; Venezuela | Trychopeplus spinosolobatus |
– | Subgenital plate 1.2× longer than combined tergites VIII–X; femora with two pairs of rounded foliate lobes, one at the apex and another in the first third of the corresponding femur length; NW Ecuador | T. mashpiensis sp. nov. |
3 | Body length > 100 mm; pronotum without ornamentation; gonapophyses shorter than the subgenital plate; Ecuador, Colombia | T. thaumasius |
– | Body length < 100 mm; pronotum with small spines; gonapophyses distinctly longer than the subgenital plate; Nicaragua, Costa Rica, and Panama | T. laciniatus |
The inclusion of Trychopeplus mashpiensis sp. nov. within the genus Trychopeplus Shelford, 1909, is based on a careful evaluation of morphological and ecological criteria. Despite clear differences from the type species Trychopeplus laciniatus (Westwood, 1874), particularly in egg ornamentation, T. mashpiensis sp. nov. shares a suite of characteristics consistent with the typical morphology and ecology of the genus. According to
Morphologically, Trychopeplus spinosolobatus (Redtenbacher, 1908) is the most similar species within the genus, as it exhibits appendages and excrescences on the head and thorax in the form of spines rather than foliaceous lobes, which distinguishes it from T. laciniatus and T. thaumasius Hebard, 1924. Unfortunately, only the female of T. spinosolobatus is known, leaving the morphology of its eggs uncertain, whether they resemble those of T. laciniatus, T. mashpiensis sp. nov., or are distinct to both of them.
One of the most significant findings of this study is the morphological differentiation between the eggs of T. mashpiensis sp. nov. and those of T. laciniatus, the only species in the genus whose eggs had been previously documented (
Despite the absence of long fringes on the eggs of T. mashpiensis sp. nov., this new species retains other characteristic features of the genus, such as the ovoid egg capsule, which is slightly longer than it is tall and wide; a pear-shaped micropyle plate displaced towards the polar area, sculpted similarly to the capsule; and an almost circular operculum with a prominently elevated outer margin, forming a hollow structure. The discovery of T. mashpiensis sp. nov.. highlights the need to reassess the characteristics used to define autapomorphies at the genus level, as the absence of fringes in the eggs of T. mashpiensis sp. nov. challenges the notion that this feature is diagnostic for the genus, as suggested by
The habitat, behaviour, and distribution of T. mashpiensis sp. nov. are consistent with those known for the genus (Fig.
In Monteverde, Costa Rica, T. laciniatus is known to feed exclusively on orchids such as Prosthechea campylostalix (Rchb.f.) W.E.Higgins and Oncidium spp. (Orchidaceae; Kenji Nishida, pers. comm.). Additionally, one of the authors observed specimens of the same species feeding on Maxillaria egertoniana (Bateman ex Lindl.) Molinari in Chagres National Park, Panama. This is noteworthy, as there appear to be no other reports of Diapheromerinae feeding on orchids, suggesting this might be a unique characteristic of the genus. Nevertheless, although various types of epiphytic orchids were observed in the natural habitat of T. mashpiensis sp. nov., it was not possible to confirm whether any of them served as host plants, as no feeding specimens were observed during the surveys.
The inclusion of Trychopeplus mashpiensis sp. nov. within the genus Trychopeplus Shelford, 1909 underscores the importance of taxonomic exploration and morphological revision in understanding Neotropical biodiversity. This study not only increases the number of known species within the genus to four, but also provides new insights into the morphological variability of eggs, which has significant implications for future identification and classification within the genus. The close phylogenetic relationship between Trychopeplus and Phanocles highlights the need for further research to clarify evolutionary relationships within the subfamily Diapheromerinae and to address the complexity of diversity within the genus.
We would like to express our gratitude to Mateo Roldán, Director of Research and Biology at Mashpi Reserve, and Estuardo Lima, guide at Mashpi Lodge, for their invaluable assistance and guidance, which allowed us to quickly familiarise ourselves with the area, facilitating the planning of our samplings. We also wish to extend our sincere thanks to Diego F. Cisneros-Heredia and Emilia Peñaherrera-Romero, from the Department of Biology at the University San Francisco de Quito (USFQ) for their unwavering support. Thanks to their collaboration, the authors have been able to realise an ambitious national research project aimed at studying and cataloguing the little-known diversity of phasmids in Ecuador.
The authors have declared that no competing interests exist.
No ethical statement was reported.
No funding was reported.
Funding acquisition: OVC. Resources: PV, OVC, FHH. Writing - original draft: PV. Writing - review and editing: PV, OVC, FHH.
Oskar V. Conle https://orcid.org/0000-0001-5609-5107
Pablo Valero https://orcid.org/0000-0002-5471-3458
Frank H. Hennemann https://orcid.org/0000-0002-6547-4704
All of the data that support the findings of this study are available in the main text.