Odontomachus davidsoni sp. nov. (Hymenoptera, Formicidae), a new conspicuous trap-jaw ant from Ecuador

Abstract One of the largest species in its genus, Odontomachus davidsoni Hoenle, Lattke & Donoso, sp. nov. is described from workers and queens collected at lowland forests in the Chocó-Darién bioregion in coastal Ecuador. The workers are characterized by their uniform red coloration, their large size (16–18 mm body length), and their frontal head striation that reaches the occipital margin. DNA barcodes (COI) and high resolution 2D images of the type material are provided, as well as an updated key for the Neotropical species of Odontomachus. In addition, a three-dimensional digital model of the worker holotype and a paratype queen scanned with DISC3D based on photogrammetry is presented, for the first time in a species description. Findings of large and conspicuous new species are uncommon around the world and suggest that these Ecuadorian rainforests may conceal many more natural treasures that deserve conservation.


Keywords
3D scan, DNA barcoding, DISC3D, integrative taxonomy, Northwest Ecuador, Ponerinae, tropical forest introduction Members of the genus Odontomachus Latreille, 1804 are among the most conspicuous and recognizable ants of the subfamily Ponerinae. All members of the genus exhibit trap jaws, a character shared with the sister genus Anochetus Mayr, 1861 (Schmidt and Shattuck 2014) and several other unrelated genera (Larabee and Suarez 2014). Trap jaws are long, slender mandibles that are mainly used for predation and secondarily in some taxa to catapult the ant into the air as a predator escape response (Larabee and Suarez 2015). Trap jaws function via a special clamping mechanism with the mandibles opening at a 180-degree angle and snap shut at high speeds upon physical contact with mechanosensory hairs (Gronenberg et al. 1993;Gronenberg 1995). Odontomachus typically comprises medium-to large-sized ants with a pantropical distribution including subtropical regions. The genus currently contains a total of 72 species (Bolton 2018), with the highest diversity found in the Neotropics and South-East Asia (Larabee et al 2016;Guenard et al 2017;Matos-Maraví et al. 2018).
Ecuador, with at least 18 Odontomachus species (Salazar et al. 2015), is among the countries showing the highest species diversity recorded for this genus. In general, Ecuadorian biodiversity is comparatively high, because the country comprises three vastly distinct bioregions: the Amazon basin in East Ecuador, the Chocó-Darién bioregion in the North-West, and the Tumbesian drylands in the South of the country which are divided by the Andes, one of the highest mountain chains in the world (Salazar and Donoso 2013;Salazar et al. 2015). While ants of the Ecuadorian Amazon have received some attention (e.g., Wilkie et al. 2010), ant research is severely lacking in the highly threatened areas of the Chocó-Darién (Donoso and Ramón 2009;Donoso 2017) and in the southern drylands (Dominguez et al. 2016;Lattke et al. 2016). Notably, the Chocó-Darién is home for several large and rare Odontomachus species, including O. mormo Brown, 1976, andO. cornutus Stitz, 1933, both of which are only known from few collections (Rodriguez 2008). Since Brown's (1976) global revision of the genus, the taxonomy of the New World species has remained relatively stable, with one additional species described in the United States (Deyrup & Cover 2004) and none for the Neotropics except for O. scalptus Brown, 1978, from Tena, in the Ecuadorian Amazon.
We describe a surprisingly large new species, i.e., O. davidsoni sp. nov., from the Ecuadorian Chocó-Darién region that rivals in size O. mormo, previously considered the largest species of New World Odontomachus. We use morphological and genetic analyses to distinguish it from other Odontomachus species and use, for the first time in insect taxonomy, textured 3D-models to present a digital version of the holotype, a queen and several other specimens.

Sampling and geographic origin
Specimens of O. davidsoni were collected and observed in field trips to the Reserva Río Canandé in Ecuador (Esmeraldas Province) from February 2018 to April 2019. We searched for specimens by walking through the forest and examining the vegetation and recently fallen trees. Alate queens were collected with light traps directly located at the Ecolodge of the Reserve. We collected exclusively by hand, and specimens were preserved in vials containing 96% ethanol. Photographs of living specimens were taken with a Nikon D5300 camera body (Nikon Corp., Tokio, JP) and a Laowa 60mm f2.8 2× macro lens (Venus Optics, Hefei, China). The Ministerio de Ambiente de Ecuador issued the permits for collection (

Photogrammetry
The worker holotype, two worker paratypes, and one paratype queen were mounted with water-soluble insect glue on the tip of an insect needle and imaged using the Darmstadt Insect Scanner (DISC3D, Ströbel et al. 2018). Specimens were imaged with extended depth of field (EDOF) using calibrated stacks of 19 images with 4 megapixels (Ströbel et al. 2018). EDOF images were taken from 398 viewing angles (in total 7562 images were recorded) and used for photogrammetric reconstruction and texturing in PhotoScan Professional 1.4.5. (Agisoft LLC, St. Petersburg, Russia) with the highest quality settings and visibility consistent mesh generation. Polygons corresponding to the insect pin were removed from the resulting mesh and the mesh was slightly smoothed (with a factor of 0.5). In addition, the holotype and queen models were textured using the "average" option resulting in 5000 × 5000 pixel texture maps. Textures were sharpened and cleaned in Adobe Photoshop CS6 13.0 (Adobe Inc., San Jose, CA, USA). We furthermore provide videos with added light effects created with Blender (Blender Foundation; Amsterdam, NL; Suppl. materials 1, 2).
Additional stacking pictures were taken with a Canon EOS 7D with a MPE 65mm lens (Canon, Tokyo, Japan) and a Keyence VHX-5000 (Keyence Deutschland BmH, Neu-Isenburg, Germany) with a Z20 lens. Stacking pictures were assembled with Helicon Focus Version 7 (Helicon Soft Ltd., Kharkiv, Ukraine) software, and further edited with Adobe Photoshop CS6 13.0 (Adobe Inc., San Kaso, CA, USA).

Morphological data
Morphological measurements of three workers (the holotype and two paratypes) and one alate queen were performed using 3D-models embedded in PDF files obtained with DISC3D. The measurements obtained through such models are more precise and reproducible than traditional ocular micrometer measurements, partly since parallax errors are avoided (see Ströbel et al. 2018). Measurements were taken with Adobe Acrobat Reader DC (version 11.0.23; Adobe Inc., San Jose, CA, USA) following the definitions described in MacGown et al. (2014) andBrown (1976), with the exception of head and petiole height measurements (see definitions below). As Brown (1976) already recognized, heads of Anochetus and Odontomachus can have a relatively trapezoid or more rectangular shape in frontal view, which is a reliable indicator to help differentiate between species. To discern between these shapes, we included the head ocular width (HoW -synonymous with HW in other studies, e.g., MacGown et al. 2014) and head vertexal width (HvW, see below). We measured two paratype workers with a binocular with measuring eyepiece only (see Suppl. material 3). The morphological values given in the species description however solely derive from measurements of the 3D scan of workers (N = 3) and queen (N = 1) for reasons of consistency. All measurements are given in millimeters. Additional to the measurements we give a detailed morphological description of Odontomachus davidsoni sp. nov. The morphological terminology, including those of surface sculpturing, is based on definitions found in Wilson (1955), Harris (1979) and Keller (2011).

Measurement definitions
All measurements are given in millimeter.

EL
Eye length. Maximum length of eye as measured normally in oblique view of the head to show full surface of eye.

FL
Femur length. Maximum length of hind femur.

HL
Head length. Maximum length of head in full-face view, excluding mandibles, measured from anteriormost point of clypeal margin to midpoint of a line across the posterior margin.

HoW
Head ocular width. Maximum width of head at ocular prominence in fullface view, measured in the same plane as HL.

HvW
Head vertexal width. Width of head at vertex in full-face view, measured in the same plane as HL. An imaginary line is drawn parallel to the cephalic posterior margin and perpendicular lines are extended anterad to where the posterolateral cephalic curve meets the lateral cephalic margin.

MI
Mandible index. ML/HL × 100 ML Mandible length. The straight-line length of mandible at full closure, measured in the same plane as HL, from mandibular apex to anterior clypeal margin.

Molecular analyses
We sequenced the classical mitochondrial barcode region for animals, a 658-base pair (bp) region of the cytochrome oxidase subunit I gene (COI), for two O. davidsoni sp. nov. specimens and six specimens of six additional Odontomachus species (O. erythrocephalus Emery, 1840, O. mormo, O. chelifer (Latreille, 1802), O. meinerti Forel, 1805, O. cf. mayi Mann, 1912, O. hastatus (Fabricius, 1804; see Suppl. material 4 for collection data). Specimens were identified by PH. We used whole specimens for non-destructive DNA extraction using the Qiagen 96 DNeasy Blood & Tissue Kit (Quiagen, Venlo, Netherlands) following the standard protocol with one exception: we shortened the protein lysis step to 2h-3h to avoid any damaging of the specimens, which keeps specimens intact and in good condition so as to serve as morphological vouchers (e.g., von Beeren et al. 2016). We amplified COI using the primer combination LCO1490 / HCO2198 (Folmer et al. 1994). PCRs were set up as described previously by von Beeren et al. (2016). Purification and sequencing of PCR products in forward and reverse direction were outsourced to Macrogen Europe B.V. (Amsterdam, Netherlands). The laboratory information management system Geneious Prime 2019.1.3 was used to process and analyse sequences (https://www.geneious.com).
Published and newly acquired data from this study were then analyzed together. We first performed several quality checks. Sequences lacking species identifications, sequences containing ambiguous bases, and sequences smaller than 400bp were sorted out. We then used the MUSCLE algorithm (Edgar 2004) to align COI sequences and, on this basis, sorted out additional sequences which showed gaps and/or additional bases in the sequence alignment. No apparent stop codons were detected in the analyzed Odontomachus dataset. Finally, we extracted unique sequences (or COI haplotypes) from the dataset resulting in 94 distinct COI sequences of 16 Odontomachus species. For eight of those specimens lateral habitus images were uploaded to BOLD. BOLD process IDs of sequences are given in Suppl. material 5.
We used a Neighbor-Joining (NJ) tree as simple clustering approach of DNA barcode data to depict genetic differences and to examine the reliability of COI as possible molecular identifier of O. davidsoni sp. nov. Note that it was not our goal to evaluate whether COI can serve as a reliable identification character in the entire genus. We thus did not define species boundaries in other Odontomachus species based on intraspecific p-distance thresholds and barcoding gaps as it is often done so in other barcoding studies. Except for our own identifications (see above) we used and relied on species identifications that were deposited together with COI sequences in GenBank. The NJ tree was analyzed in MEGA 10.0.5 (Kumar et al. 2018) based on p-distances with pairwise deletion of missing data. P-distances simply give the proportion of bases that differ in pairwise sequence comparisons. Metadata of the NJ tree are given in Suppl. material 6 as Newick formatted file.

Key to Neotropical Odontomachus species
This key is a modification of the keys of Rodriguez (2008) and Brown (1976), both of which contain many additional helpful figures as well as detailed morphological descriptions. Please note that this key does not include the species native to the USA such as the Florida endemic O. relictus Deyrup & Cover, 2004, for which we recommend using the key of MacGown et al. (2014).
From the Rodriguez (2008) key only the herewith described O. davidsoni sp. nov. is added as new. However, the classification of Odontomachus brunneus has been cleared up. Originally, it was thought to be distributed in South and Central America, but it is now clear that it is restricted to the Southern USA, and previous material that has been identified as such probably belongs to O. ruginodis Smith, 1937(MacGown et al. 2014.
For easy identification, we recommend to point mount workers of Odontomachus by bending the tip of the point and gluing it to the pleura so as to leave the space between the hind coxae exposed. This is because the metasternal process is an important identification characteristic and it might be obscured otherwise.
Long (TL > 17 mm), but slender, ferruginous to yellow brown body with striae on cephalic dorsum from antennal insertions to vertex, mandible with over 15 preapical teeth and denticles, pronotal dorsum with concentric to transverse striae. Petiole strongly pedunculate with posteriorly inclined apical spine, gaster smooth and shining.
Description of the holotype worker. Head elongate in dorsal view, anterior and posterior margins approximately of same width, posterior cephalic margin mostly transverse; head widest across eyes, at anterior one-third of head length; lateral cephalic margin posterior to eye sinuous. Median furrow deep, extends anterad to antennal fossa where it fades; occipital ridge distinctly delineated by antennal fossa, extending posteromedially, joining broad ridge that runs parallel to median furrow. Extraocular furrow broad and shallow, temporal prominence broad and weakly elevated. Cephalic surface with well-defined striae that diverge posterad from between frontal carina, reaching vertex, striae fade away on most of lateral cephalic surface with some striae reaching posteroventral cephalic surface. Ocular ridge smooth closest to eye and striate towards cephalic median region. Cephalic dorsal surface anterad of eye and between eye and antennal sclerite mostly smooth. Scape slender and slightly arched, SL longer than HL, scape widest just anterad of mid length, finely punctulate; funicular segment elongated and slender, segment I half as long as segment II.
Median clypeus mostly smooth and shining, posteriorly projecting as flattened triangular surface between frontal carina; carina defines narrow elevated region that descends posteriorly and extends to antennal fossa; frontal carina narrow, width not greater than scape width; carina steeply elevated over posteromedian clypeal surface. Ventral cephalic surface mostly smooth and shining. Labium drop-shaped, anteroventral surface very convex, PF 4,4. Buccal cavity with lateral hypostomal tooth. Mandibular masticatory margin with basal row of six denticles and eleven blunt triangular, relatively short teeth apicad of denticles. One or more teeth closest to apex may be broken. Mandibular apex tridentate, ventral tooth with basal tooth. Mandibular dorsal surface mostly smooth, with sparse piligerous punctulae, but dorsolaterally with abundant punctulae, ventral surface smooth and shining.
Pronotal dorsum with concentric striation that become progressively transverse and elongate medially towards posterior margin, in lateral view striae appear anteriorly transverse, medially curving and U-shaped, posteriorly oblique to almost vertical. Posterolateral pronotal margin with short convex lobe. Mesosoma relatively slender and elongate, in lateral view pronotal dorsal margin straight to weakly convex, forming a posteriorly ascending slope, mesonotum anterior margin slightly higher than posterior pronotal margin, mesonotal dorsal margin mostly straight to weakly convex, descending to metanotal groove. Dorsal mesosomal margin between metanotal sulcus and metanotal spiracle forms brief convexity, propodeal anterodorsal margin brief and convex, dorsal margin mostly straight, three times longer than declivity, declivity forms blunt obtuse angle with dorsal margin. Propleuron mostly smooth and shining with narrow transverse band of sparse weak rugulae anteriorly and posteriorly.
Mesonotum with transverse striae that extend uninterrupted laterally to anepisternum and ventrally to mesosternum, katepisternum mostly smooth and shining except for sparse striae anteriorly and posteroventrally. Bulla of metathoracic spiracle semispherical, weakly sculpted, opening shaped as transverse slit. Propodeum and metanotum transversely striate. Mesometapleural suture distinct, propodeal-metapleural suture weakly impressed. No carina or visible suture between mesopleuron and mesosternum, mesosoma in hypothetical cross-section at mid-length forms relatively uniform ovoid. Mesosternum with median longitudinal region raised as low and broad convex ridge; metasternal process bidentate, teeth short and blunt. Propodeal spiracle slit-shaped, transverse to oblique, not elevated.
Petiole in lateral view slightly pedunculate, node shaped as posteriorly sloping cone with acute apical needle, anterior node margin weakly convex, posterior margin vertical, straight to weakly convex; anteroventral process prominent, triangular; node smooth and shining. Abdominal tergite 3 in lateral view with anterodorsal margin forming single convexity to posterior margin, ascending posterad at approximately 45°; ventral margin of tergite 3 briefly concave at prora, then broadly convex and

A B
mostly at the same level as prora. Constriction between abdominal segments 3, 4 weak to negligible; gaster smooth and shining.
Coxae mostly smooth with abundant minute piligerous punctulae, punctulae denser on tibiae. Protibial apex with single seta, spur with basal translucent lamella. Probasitarsus with row of short, stiff hairs and parallel row of short setae opposite spur. Meso and metatibial apex each with two spurs, one pectinate, one simple; each also with 3 setae, each seta widely separated from each other. Body pilosity generally short and scattered with little pubescence; dorsal surface with few standing hairs: one on head where antennal fossa and nuchal carina almost meet, few on gastral sterna. Head and mandibular dorsum with sparse appressed pubescence, hairs straight on mandible and arched on head. Mandibular ventral surface next to masticatory margin with row of five flagellate long hairs plus two long trigger hairs at base. Scape with dense appressed pubescence, no standing hairs. Mesosoma with sparse appressed to subdecumbent small hairs, node with longer hairs; gaster mostly with sparse short, appressed to decumbent hairs with suberect hairs towards posterior end of gaster. Mandible and other buccal appendages, antenna, tibiae, and tarsi ferruginous brown to brown. Body mostly ferruginous to brownish yellow, head dark anterad and gaster darker posterad; trochanters and apex of femora tend to be darker. Mesosoma developed for wings, head with three ocelli. Queen with larger dimensions than worker: HoW > 3.3; MsL > 6.5; PrW >1.9 mm., otherwise similar.
Male. Unknown. Etymology. The species epithet is a patronym in genitive case honoring Stuart Carleton Davidson, the founder of Clyde's Restaurant Group, Washington, DC. Stuart had a lifelong interest in our environment, and would have loved this amazing ant.
Comparison to similar species. Odontomachus davidsoni most closely resembles O. hastatus by sharing a relatively large size, a red to brown color, a head which has in dorsal view a great difference between ocular and vertexal width, a relatively slender habitus, a bilobed metasternal process (Fig. 4A), and a pedunculate petiole with a posterior inclining node topped by a long dorsal needle. Together with O. mormo both species also share an evenly convex anterior margin of abdominal tergite III that in lateral view ascends posterad at an approximate 45° angle (Fig. 4B). When using the key to Neotropical Odontomachus species by Rodriguez (2008) this species will be taken easily to couplet 13, whereupon it will not fit any of the two alternatives: O. ruginodis nor O. laticeps. It is clearly larger than O. ruginodis, which also differs in its dark brown color, sessile petiole, and a very short stubby petiolar needle. O. laticeps is smaller, dark brown, with a sessile and relatively erect petiole bearing a shorter dorsal needle. Using the identification key in Brown (1976: 111), or the key in Antwiki (2015), this species is easily taken to couplet 14 where it becomes stuck as it fits neither alternative, O. bauri nor O. laticeps. Both of these ants are much smaller, dark brown, have a sessile, erect petiolar node with a relatively shorter dorsal needle, and the anterior dorsal margin of abdominal tergite III in lateral view is mostly vertical. Molecular analyses. We successfully amplified DNA barcodes of two Odontomachus davidsoni workers, a 569 bp fragment and a 668 bp fragment (GenBank accession numbers MN454765 and MN454766, respectively). The two specimens came from the same nest and had identical sequences. Odontomachus davidsoni barcodes were clearly distinguishable from COI sequences of other Odontomachus species (Fig.  5) as indicated by the minimum interspecific p-distance of 0.09 in pairwise comparisons (range of p-distances in 94 pairwise comparisons: 0.09-0.14; Fig. 5). A search in the BOLD identification database for the closest sequence match yielded similar results of 90.76% and 90.67% sequence similarity to O. chelifer (private, not pub- we frequently visited a tree in a selectively logged area of the Canandé Reserve where a few workers of the species were spotted. Foraging workers were observed predominantly during nighttime between 8 pm and 11 pm. On at least five occasions during daytime (i.e., between 9 am and 5 pm) the plot was visited, but only once foraging Figure 5. Neighbor-Joining (NJ) tree of Odontomachus COI sequences. The NJ tree is based on pdistances (scale bar). First digit in parentheses gives the number of identified COI haplotypes of a given species and the second one the total number of available COI sequences for this species. GenBank accession numbers are given in Suppl. material 5 and Newick tree file are given in Suppl. material 6. workers were observed. Although their exact nest position was not detected, workers were predominantly foraging on a liana attached to a Cecropia tree. The tree had a diameter of 63 cm at breast height and an estimated height of 20 m. Workers could be observed walking straight up on it until they were out of sight in a height of approx.  10 m. Workers were never seen foraging on the ground, and we thus assume that they primarily forage in the canopy. Workers were observed to sit still on the surface of leaves with their mandibles open, probably waiting to ambush prey (Fig. 7).
On the 11th of February 2019 we collected what looked like a complete nest in a fallen branch (Fig. 8;GPS data: 0.5238N, 79.2130W). The nest contained one dealate queen and 18 workers, as well as brood in all development stages (Fig. 9). We assume that this colony was not fully grown because it contained no alates (despite other colo-  davidsoni. This colony was kept in the field laboratory after taking it out from the twig nest (Fig. 8). The sole dealate queen is marked with a red arrow. nies having alates at this time). The single nest entry was located under a bromeliad (Fig. 8A). We opened all parts of the nest with a machete, revealing a 40cm long tubular chamber within the center of the branch (Fig. 8B). It does not look like the ants themselves carved it, hence it was probably a pre-existing cavity.
We kept the colony for three months (11 February-15 April 2019) for further observations. The colony accepted various smaller insects as food, including flies, crickets, and termites. However, insects larger than 2 cm (e.g., large cicadas, moths, large crickets) were usually not accepted. Furthermore, the colony had ad libitum access to sugar water which was frequently visited. In accordance with field observations, the colony showed most activity during nighttime. No recruitment to offered food resources was observed. Due to the possibly threatened status of this ant species, the colony was released at the end of our observation time on a tree bromeliad nearby the Canandé lodge.

Discussion
We here formally described the species Odontomachus davidsoni. It is morphologically and genetically different from any other of the New World Odontomachus species. It rivals in size O. mormo, the largest known Odontomachus in the Americas, but the dark brown color, more sessile and robust petiole, mostly smooth cephalic dorsum, and lack of a metasternal process in O. mormo will easily permit the distinction between the two species. Unfortunately, there are few measurements available for gauging the dimensions of O. mormo (Brown 1976: 118;Rodriguez 2008: 156) but it seems safe to affirm that together with O. chelifer these species share the position as the largest known Odontomachus in the Americas.
Sequence similarities of COI barcodes suggested that O. davidsoni might be most closely related to O. hastatus, O. mormo, and O. chelifer. However, more informative phylogenetics/-genomics analyses are necessary to draw robust conclusions. This is because a single mitochondrial locus does not allow us to reliably infer phylogenetic relationships and because our species coverage is incomplete (ten Neotropical Odontomachus species do not possess published barcodes). Morphological characters suggest that Odontomachus davidsoni is most closely related to Odontomachus hastatus, which shares the arboreal and nocturnal foraging lifestyle (Camargo and Oliveira 2011;Rodrigues and Oliveira 2014 Our species description is accompanied by 3D scans of three workers and a queen (Fig. 3, Suppl. material 8). This offers morphological details of the new species to the reader and the ability to take exact trait measurements. 3D imaging techniques, and in particular micro-computed X-ray tomography (µCT), are becoming more frequently used in taxonomy and functional morphology, including studies on ants (Faulwetter et al. 2013;Akkari et al. 2015;Garcia et al. 2017;Sarnat et al. 2017;Staab et al. 2018). Garcia et al. (2017) provided a comprehensive overview of the benefits and caveats of µCT scans for such purposes. The 3D scans used in our study were produced via photogrammetry. This technique has some advantages as well as disadvantages over µCT scans, e.g., it is comparatively inexpensive and requires little manual work, but it provides no internal structure and has a comparatively low spatial resolution (Ströbel et al. 2018). The resulting surface model can thus lack taxonomically important structural features such as the head striation in the case of O. davidsoni. On the other hand, the resulting 3D surface models are texturized, thus also providing information on specimen color, which is lacking in µCT scans. A further disadvantage of DISC3D scans is that structures that are obscured in the physical specimen, e.g., through leg positioning or characters laying underneath the glue, are not recovered in a resulting 3D model. Overall, we argue that the 3D scans are a good addition to the traditional morphological description and stacking images by providing valuable 3D models that everyone can easily access and use for reliable trait measurements. Additionally, the 398 EDOF images, that the 3D models are based on, allow for an even more detailed inspection of the specimens in comparison to the texture on the 3D model.
The new species was discovered in the Chocó-Darién bioregion in Ecuador, probably one of the most biodiverse regions on earth, and at the same time one of the most threatened ones (Dinerstein et al. 1995;Olson and Dinerstein 1998;Myers et al. 2000). Research in this region is scarce, with many undescribed endemic species still awaiting scientific discovery and description ). The fact that a large and conspicuous ant like the herein described trap-jaw ant O. davidsoni remained unknown to science until now suggests that a hidden diversity remains to be discovered in this region. Similar to other biodiversity hotspots, increasing deforestation and conversion of forests to agriculture threatens the biodiversity of the Chocó-Darién bioregion, bearing the risk that many endemic and even yet undescribed species become extinct before being detected. With the description of a new, conspicuous trap-jaw ant, probably endemic to the region, we hope to provide additional reasons to protect this threatened biodiversity hotspot.

Conclusion
Odontomachus davidsoni is a noteworthy discovery in a vastly understudied and highly threatened area, the Chocó-Darién region of Ecuador. We sincerely hope that conservation efforts will continue and expand to protect this unique and important biodiversity hotspot. local support from the park staff in the Canandé and Tesoro Escondido reserve, that made the field collection easier and made two great field stays possible: Bryan Amayo, Alcides Zombrano, Roberto de la Cruz, Jorge Zambrano, Amado de la Cruz, Yadria Giler, Patricio Encarnación, and Vanessa Moreira.
The species name was auctioned for a good cause at the anniversary of the Rainforest Trust, and we like to thank them and the highest bidder for this opportunity to aid in the conservation efforts and research in the Chocó area.
We would like to thank Brian L. Fisher as well as three reviewers for helpful comments on the manuscript. We acknowledge support by the German Research Foundation and the Open Access Publishing Fund of Technische Universität Darmstadt. PH was supported by a scholarship from the German National Academic Foundation. CvB received funding from the German Research Foundation (DFG: BE 5177/4-1 & BE 5177/4-2). SS was funded by the German Federal Ministry of Education and Research (BMBF), project NOVA (05K2016 / 05K16RDD).