Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery

A fundamental problem in biodiversity science is determining the number of species in any taxon, and there is a growing awareness that cryptic diversity contributes to this problem – even in well-studied groups. Discovering cryptic species requires several lines of evidence to elucidate congruent patterns across data-types, and distinguish unrecognized species. Tiger beetles are among the most well-studied insect groups; yet few new North American species have been described since the mid-20th century, suggesting that that the number of morphologically distinct species is reaching an asymptote. We explore the possibility that more species exist in the fauna as cryptic species, by analysing a broad geographic sample of all species in the genus Dromochorus. We employ a ‘taxonomic congruence’ approach, where we first generate species hypotheses from patterns of reciprocal monophyly across the mitochondrial and nuclear datasets, and test these hypotheses through congruence with population structure, morphological measures and ecological divergence. We find broad congruence that supports eight species of Dromochorus, more than doubling the known diversity. We also validate a previously ambiguous taxon, and re-describe previously named species. Lastly, we identify new diagnostic morphological characters, include an updated dichotomous key and provide updated natural history/ecological characteristics for the genus and individual species

Dromochorus pilatei

<p> <i>DROMOCHORUS PILATEI</i> GUÉRIN- MÉNEVILLE, 1845</p> <p>(FIG. 9H)</p> <i>Common name</i> <p>Cajun tiger beetle.</p> <i>Type locality</i> <p>‘Velasco, Texas’ (translation). Holotype probably in MHNP, Paris (Bousquet, 2012).</p> <i>Synonymy</i> <p> <i>Cicindela maga</i> LeConte, 1875: 161. Type locatity ‘near Lake Ponchartrain, Louisiana’. Syntypes (2) in MCZN. Synonymy established by Sallé (1877).</p> <i>Taxonomic history</i> <p> This is the type species for the genus <i>Dromochorus</i>, as described by Guérin-Méneville (1845). Two remarkably green specimens were collected by LeConte and described as <i>Cicindela maga</i> (1875) from the vicinity of Lake Ponchartrain, LA.</p> <i>Distribution</i> <p> <i>Dromochorus pilatei</i> is known from south-east Texas in the vicinity of the Brazos River east to the Mississippi River in Louisiana, north to Natchitoches, LA. The Lake Ponchartrain record is uncertain. This flightless beetle has otherwise never been found east of the Mississippi River except for LeConte’s specimens. There have been multiple attempts to find the beetle in this area (Graves & Pearson, 1973; D.P. Duran, pers. obs.), but these have been unsuccessful. We regard this record as a potential error until further verification.</p> <i>Diagnosis</i> <p> This species cannot be confused with any other <i>Dromochorus</i>. The distinctive body form, elytral coloration with bronze and green reflections, prominent green subsutural foveae and complex surface texturing are diagnostic. Some individuals have a strong green-bronze sheen over all surfaces, and this trait appears to be more prevalent towards the eastern part of the species range.</p> <i>Description</i> <p> Small- to medium-sized <i>Dromochorus</i>. Body length 10.5–14.7 mm, mean ♀ 13.3 mm, mean ♂ 12.4 mm. Head slightly wider than pronotum. <b>Head predominantly brown with cupreous to brassy reflections, green to blue to violet reflections mostly concentrated near the anterior margin and edges of the supraorbital region. In some specimens, bright green to green-blue reflections present throughout</b>. Fine rugosity often present on the frons and vertex. All head portions glabrous except for two supraorbital setae next to each eye. Frons concave in median area, especially in males, bulging towards slightly convex near anterior margin, clearly delimited from clypeus, gradually blending into vertex. Genae metallic blue to violet, with</p> <p> shallow, longitudinal striae gradually ending at border of vertex. Clypeus bronze with green to blue reflections throughout; female clypeus more extensively greenblue to blue-violet. Male labrum tridentate with 6–8 setae, entirely pale ochre-testaceous, with a thin darkbrown to black border; female labrum tridentate with 6–8 setae, entirely dark-brown to black with polished metallic cupreous to green reflections. <b>Maxillary palpi pale yellow-ochre; apical segment dark-brown to black, often with metallic purple and green reflections</b>. Labial palpi coloured similarly to maxillary palpi. Antennae normal length, reaching back to humerus and basal third of elytron, slightly longer in male than female; scape dark testaceous to black with metallic reflections of violet, cupreous and green, with 2–3 apical setae; pedicel dark testaceous with metallic reflections of violet, cupreous and green, lacking any setae; flagellum dark testaceous, antennomeres 3–4 with metallic violet and green reflections, densely clothed in short, white setae, antennomeres 5–11 dull-textured without metallic reflections and possessing erect setae in apical rings only, covered with fine pubescence throughout.</p> <p> <i>Thorax</i>: Pronotum 1.8–3.2 mm in length, mean ♀ 2.8 mm, mean ♂ 2.6 mm; width 2.3–3.4 mm, mean ♀ 2.9 mm, mean ♂ 2.7 mm. Pronotum brown with cupreous, brassy or violet reflections; some specimens with green to green-blue reflections throughout, slightly wider than long, widest near anterior margin, width to length ratio 1.0 to 1.2, setae sparse to regularly spaced, mostly present along lateral third of dorsal surface; disc finely rugose, with thin but distinct median line, with well-defined shallow sulci present anteriorly and posteriorly; notopleural sutures clearly defined, not visible from dorsal view; proepisternum black with weak to strong iridescent violet reflections, glabrous. Elytra elongate, dorsal surface convex, 6.4–9.0 mm length, mean ♀ 8.2 mm, mean ♂ 7.6 mm, shape similar in both sexes, but slightly wider in female, especially toward apical third; sutural spine absent, microserrations not present on elytral apices; elytral <b>surface dull with complex texturing and infuscations, with regular small pits present throughout disk, as well as larger foveae. Bright green or blue reflections generally present in most to all pits and foveae</b>.</p> <p> <i>Legs</i>: Pro-, meso- and metacoxae dark-brown to black, may have iridescent blue reflections, scattered setae on pro- and mesocoxae, fewer on metacoxae; pro- and mesotrochanters with a single erect seta, metatrochanter glabrous, trochanters dark brown-testaceous; femora dark-brown black with metallic violet and bronze reflections, densely clothed in decumbent white setae; tibiae testaceous brown, clothed with setae of two types: sparser brown-testaceous long setae and dense short decumbent white setae; two tibial spines present; tarsi brown-testaceous, first three dilated protarsomeres in male with dense greyish-white setal pad.</p> <p> <i>Abdomen</i>: Venter mostly dark-brown to black with faint violet reflections. Erect brown setae present on ventrite 1. Ventrites 2–6 have sparse short, brown, erect setae present throughout, but often abraded.</p> <p> <i>Ecology/natural history</i></p> <p> Adults appear to be active from mid-May to mid-July. <i>Dromochorus pilatei</i> can be found in significant numbers during peak adult activity (early to mid-June), along shaded, dark soil trails in riparian zones or near the banks of bayous, lakes and salt marshes. Of the <i>Dromochorus</i>, <i>pilatei</i> has the strongest affinity for heavily forested areas. The species is tightly associated with blackish, rich soils with high humus content, which are produced in the forest via decaying vegetation. In contrast, <i>D. pruininus</i> and <i>D. belfragei</i> are associated with disturbed clay deposits that contain less organic matter (red iron oxidized clays or black clay loam). In our observations, <i>D. pilatei</i> apparently avoids the lighter coloured soils that can also be present in its habitat.</p> <p> This species can be found foraging/mating along man-made trails, disturbances or semi-open vegetated areas of applicable forest. Beetles appear to be concentrated on the edges of trails, sometimes with moderate to thick vegetation. <i>Dromochorus pilatei</i> is the only member of the genus that has been collected at lights at night (J. Back, pers. comm.). However, it was collected in small numbers, and it is likely that its presence was due to a high density of prey in the area, created by the lights. Traditionally thought to be crepuscular and perhaps nocturnal (Graves & Pearson, 1973) in this habit, we now know this species is active throughout the day in well-shaded areas.</p>Published as part of <i>Duran, Daniel P., Herrmann, David P., Roman, Stephen J., Gwiazdowski, Rodger A., Drummond, Jennifer A., Hood, Glen R. & Egan, Scott P., 2019, Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery, pp. 250-285 in Zoological Journal of the Linnean Society 186</i> on pages 278-279, DOI: 10.1093/zoolinnean/zly035, <a href="http://zenodo.org/record/3089237">http://zenodo.org/record/3089237</a&gt

Dromochorus belfragei Duran & Herrmann & Roman & Gwiazdowski & Drummond & Hood & Egan 2019

DROMOCHORUS BELFRAGEI SALLÉ, 1877 (FIGS 7B, 9B) Common name Loamy-ground tiger beetle. Type locality ‘Texas–Dallas, Wasco (presumed to be a misspelling of Waco), etc., on the banks of the Trinity River’ (English translation). Syntypes unknown, probably in MHNP (Bousquet 2012). Synonymy Dromochorus bellefragei Heyne, 1893 (unjustified emendation). Dromochorus sericeus Casey, 1897: 294. Type locality ‘Texas’. Two syntypes in USNM, Washington DC (synonymy established by Leng, 1902). Taxonomic history Dromochorus belfragei has been a catch-all taxon, and many populations of Dromochorus were lumped under this name in the literature or in museum collections prior to this revision. Dromochorus pilatei and D. velutinigrens are the only nominal taxa that have never been considered conspecific with D. belfragei. Based on morphology, ecology, biogeography, mtDNA genealogy and multilocus genetic data, D. belfragei (sensu stricto) is circumscribed as a separate species from three other distinct species, D. pruininus, D. knisleyi sp. nov. and D. minimus sp. nov. Occasional hybridization with D. knisleyi has been observed where their ranges come in contact, and this is further supported by evidence of mtDNA introgression. Distribution Dromochorus belfragei is known to occur from the north-western panhandle of Texas and southern Oklahoma to south-eastern Texas. Previous literature described a more extensive range from south-eastern Colorado (Michels et al., 2008) to Tamaulipas, Mexico (Cazier, 1954). The former record now appears to be an error (Michels, pers. comm., 2015), and the latter would appear to belong to D. chaparralensis sp. nov. One specimen from the AMNH was labelled ‘St. George, Utah’, although this locality would not appear plausible. The range of D. belfragei comes close to several other species. In particular, D. belfragei is nearly sympatric with D. pruininus in several places (Fig. 3; see D. pruininus account). In eastern and southern Bexar County, TX, this species is found sympatrically with D. knisleyi, and possibly D. minimus. Diagnosis This species can be distinguished from all other similar Dromochorus by the presence of finely to coarsely pitted black elytra that are not frosted in texture, in conjunction with maxillary palpi that have the apical segment darkest, with dark yellow-ochre to dark amber coloration in other segments (Fig. 8). Most populations of D. belfragei possess at least small subsutural foveae, but these lack metallic reflections. Southern and eastern populations may have subtle dark infuscations on the elytra. Dromochorus belfragei is most likely to be confused with D. pruininus, knisleyi or welderensis. It can be separated from these taxa by the following: 1. Dromochorus pruininus has a frosted blue sheen on the elytra and the entire dorsal surface, and it lacks any pits or subsutural foveae. The maxillary palpi in D. pruininus are pale yellow-ochre with a dark apical segment, whereas D. belfragei has darker yellow-red to red testaceous palpi with a dark apical segment. 2. Dromochorus knisleyi is similar to D. belfragei, but has more prominent subsutural foveae, often with bright metallic blue, green or gold reflections. In D. knisleyi, the maxillary palpi are always dark in all segments, whereas in D. belfragei, the apical segment is darker than the preceding. Infuscations are always present in D. knisleyi and are usually absent in D. belfragei. Ecologically, D. knisleyi is found in upland juniper woodland in the Edwards Plateau, and D. belfragei is found outside of this region, in clay soils associated with larger riparian systems. The two species appear to hybridize along a narrow contact zone at the edge of the Balcones Escarpment in south-eastern and south-central Texas. Both species and their hybrids may be found in this area. The existence of a hybrid zone was further supported by mtDNA data (Fig. 2). 3. Dromochorus welderensis has a smooth velvety black elytral surface (may have metallic blue-violet reflections), and never has pitting or subsutural foveae. The maxillary palpi are always dark in all segments, whereas in D. belfragei, the apical segment is darker than the preceding. Description Medium- to large-sized Dromochorus. Body length 11.6–15.2 mm, mean ♀ 14.5 mm, mean ♂ 13.2 mm. Head slightly wider than pronotum. Head predominantly black with blue reflections mostly concentrated near the anterior margin and edges of the supraorbital region. Fine rugosity often present on the frons and vertex. All head portions glabrous except for two supraorbital setae next to each eye. Frons concave in median area, especially in male, bulging towards slightly convex near anterior margin, clearly delimited from clypeus, gradually blending into vertex. Genae bright polished metallic violet to blue, with shallow, longitudinal striae gradually ending at border of vertex. Clypeus mostly black, with patches of metallic blue or violet reflections; clypeus may be nearly entirely blue to violet in females. Male labrum tridentate with 6–8 setae, central area pale ochre-testaceous, with a thin dark-brown to black bor- der posteriorly and sometimes anteriorly, dark-brown to black laterally; in some populations, the pale central area of the labrum may exist as a small spot, in others the pale area may cover more than two-thirds of the total labrum surface; female labrum tridentate with 6–8 setae, entirely dark-brown to black with polished metallic cupreous to green reflections. Maxillary and labial palpi with apical segment darker than other segments; basal to penultimate segments yellow-ochre to dark red-amber, often with metallic purple and green reflections. Antennae normal length, reaching back to humerus and basal third of elytron, slightly longer in male than female; scape dark testaceous to black with metallic reflections of violet, cupreous and green, with 2–3 apical setae; pedicel dark testaceous with metallic reflections of violet, cupreous and green, lacking any setae; flagellum dark testaceous, antennomeres 3–4 with metallic violet and green reflections, densely clothed in short white setae, antennomeres 5–11 dulltextured without metallic reflections and possessing erect setae in apical rings only, covered with fine pubescence throughout. Thorax: Pronotum 2.5–3.4 mm in length, mean ♀ 3.1 mm, mean ♂ 2.8 mm; width 2.8–3.6 mm, mean ♀ 3.4 mm, mean ♂ 3.1 mm. Pronotum black, with some dark-blue reflections, especially in sulci, slightly wider than long, widest near anterior margin, width to length ratio 1.0 to 1.2, setae sparse to regularly spaced, mostly present along lateral third of dorsal surface; disc finely rugose, with thin but distinct median line, with well-defined shallow sulci present anteriorly and posteriorly; notopleural sutures clearly defined, not visible from dorsal view; proepisternum black with weak to strong iridescent blue reflections, glabrous. Elytra convex, elongate, 7.1–9.7 mm length, mean ♀ 8.8 mm, mean ♂ 8.2 mm, shape similar in both sexes, but slightly wider in female, especially toward apical third; sutural spine absent, microserrations not present on elytral apices; elytral texture dull, with regular small pits present throughout disk, elytral coloration black, often with blue reflections near humeral region; elytral maculations absent; infuscations rarely present; subsutural foveae, when present, only slightly more prominent than other pits on the elytral disk; subsutural foveae lacking bright metallic reflections, except rarely in basal area. Legs: Pro-, meso- and metacoxae dark testaceous to black with iridescent blue to violet and cupreous reflections, with numerous setae; pro- and meso- trochanters with a single erect seta, metatrochanter glabrous, trochanters dark brown-testaceous, dark brown-testaceous; femora black with metallic violet and green reflections, densely clothed in decumbent white setae; tibiae testaceous brown, clothed with setae of two types: sparser brown-testaceous long setae and dense short decumbent white setae; two tibial spines present; tarsi brown-testaceous, first three dilated protarsomeres in male with dense greyish-white setal pad. Abdomen: Venter mostly black with occasional metallic violet reflections. Decumbent white setae present on ventrite 1. Ventrites 2–6 have sparse, short, brown erect setae present throughout, but often abraded. Ecology/natural history Dromochorus belfragei adults are active between mid- May and early July in most of its range (e.g. central to north TX) and late June to late July in northern part of its range (e.g. OK to panhandle of TX). Dromochorus belfragei can be found in natural and managed forested and agricultural areas (e.g. pecan groves) that have semi-open shaded areas or trails beneath the canopy. Soils in these areas can be dark, red to black in color, clay to clay-loam, cracked and sometimes moist in low areas that are heavily trampled by cattle. Adult beetles tend to avoid the lighter coloured sandy areas that are exposed to full sunlight on the forest edges. Despite the common name, this species appears more closely associated with soils that possess high clay content, more so than loam. The preferred habitat of D. belfragei is generally associated with larger riparian systems, although the beetles are not typically found near the water’s edge and we have found them over 3 km from water. They appear to have a wider ecological niche than most Dromochorus; their habitat and geographic distribution encompass a larger number of ecoregions than other species (Fig. 3; Table 1). Dromochorus belfragei and D. pruininus have similar but non-overlapping ranges, and they may be separated by ecological barriers, at least in some areas. In the DFW area of North Texas, the species has been reported a few kilometers from D. pruininus (Pearson et al., 2006), but the two appear to be separated by a narrow extension of the EPA Level IV Eastern Cross Timbers ecoregion, which is not suitable for either species. The forested undergrowth of this area is extremely dense in many areas, and may not possess the necessary surface soil conditions for either species to persist. Dromochorus belfragei may be more susceptible to urbanization than D. pruininus, as none have been collected in the DFW area (Tarrant Co.) since the 1970s, whereas D. pruininus appear much more tolerant to these disturbances and may be abundant in semi-open grassy areas where trails have been established in riparian parks (Dallas, Collin Co.). Thought to be crepuscular, this species is active throughout the day in shady areas or when overcast. Similar in behaviour to D. pruininus and D. pilatei, this species has been observed using soil cracks for escape, especially during dry conditions when virtisolic cracks are pronounced. Like other Dromochorus, D. belfragei frequently moves to vegetated cover to escape when pursued.Published as part of Duran, Daniel P., Herrmann, David P., Roman, Stephen J., Gwiazdowski, Rodger A., Drummond, Jennifer A., Hood, Glen R. & Egan, Scott P., 2019, Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery, pp. 250-285 in Zoological Journal of the Linnean Society 186 on pages 269-271, DOI: 10.1093/zoolinnean/zly035, http://zenodo.org/record/308923

Dromochorus

GENUS DROMOCHORUS GUÉRIN- MÉNEVILLE, 1845 Type species Dromochorus pilatei Guérin-Méneville, 1845. By monotypy. Taxonomic history Dromochorus was described by Guérin-Méneville (1845) as a new genus, believed to be most closely related to ‘ Apteroessa and especially Dromica ’. This perceived relatedness was due to the remarkable similarity in gestalt, although several morphological differences were identified, especially with respect to the mouthparts, such as the maxillary and labial palpi, and labrum. Subsequent authors have not shared his view about the systematic placement of the genus within the larger tiger beetle clade. In his revision of the Cicindelinae, Horn (1908) placed Dromochorus in the subtribe Cicindelina, and Dromica in a separate subtribe, Prothymina (Horn 1910). More recent molecular phylogenies have supported Horn’s (1908) treatment, finding Dromochorus to be nested within a clade of other Nearctic Cicindelina (Vogler & Welsh, 1997; Barraclough & Vogler, 2002; Pons et al., 2004; Vogler et al., 2005), and Dromica to be more related to Prothyma (Galián, Hogan & Vogler, 2002). Any similarities between Dromochorus and Dromica must, therefore, be the result of convergent evolution owing to their similar habitats and microhabitats. The Dromochorus species have sometimes been treated as a distinct genus (Guérin-Méneville, 1845; Sallé, 1877; Fleutiaux, 1892; Casey, 1897; Rivalier, 1954, 1963, 1971; Johnson, 1991; Wiesner, 1992; Erwin & Pearson, 2008; Bousquet, 2012; Pearson et al., 2015); or viewed to be a synonym of Cicindela (e.g. LeConte, 1875; Leng, 1902; Harris, 1911; Horn, 1915; Harris & Leng, 1916; Cazier, 1954; Arnett, 1963; Willis, 1968; Bousquet & Larochelle, 1993; Arnett & Thomas, 2000), with some North American workers recognizing the taxon as a subgenus (Boyd, 1982; Freitag, 1999). Despite the variety of treatments, justifications for different taxonomic ranks were almost never given. Recent phylogenies have given support to many of the named clades within the Cicindela sensu lato (Pons et al., 2004; Vogler et al., 2005; Gough et al., in review), and these generally correspond to groups recognized in Rivalier’s revision (1954, 1963, 1971), including the Dromochorus. Based on the aforementioned research, and our own mtDNA tree (Fig. 2), Dromochorus was recovered as a well-supported monophyletic lineage, and sister to another clade of Nearctic tiger beetles. As such, we recognize the group as a distinct genus. Although Dromochorus may appear nested within Cylindera in our tree, this latter group is polyphyletic (Gough et al., 2018), as previously believed by many workers, and the sister clade to Dromochorus is being named as a new genus. Diagnosis Dromochorus are separable from all other North American tiger beetle genera by the following combination of characters, present in the adult stage. Beetles are flightless and lack flight wings, but the elytra are not fused. The elytra are oval shaped, and completely lacking pale maculations. The dorsum is dark, usually black or brown, but may also have a frosted blue, violet, grey or green sheen. The legs and tarsi are clothed in decumbent setae. In subsequent species descriptions, the most salient or diagnostic characters are indicated in bold. Rarely are any of these characters diagnostic by themselves, but the combination of these characters may be. Distribution Dromochorus are geographically restricted to the south-central United States and adjacent Mexico (Fig. 3). Texas is the centre of diversity, and all eight species are found there, at least in part of their ranges. Records from Mexico are few and imprecise. Historically, D. belfragei was the only species recorded from Mexico, although it would appear as if these populations belong to D. chaparralensis sp. nov., described in this treatment. In general, Dromochorus are found at low elevations; apparently, they do not occur in montane environments, such as the Ouachita Mountains of Arkansas and Oklahoma, which border a section of the eastern range of D. pruininus. Most Dromochorus are found below 500 m, with only the westernmost populations of D. belfragei occurring at elevations up to 1000 m. Ecology/natural history Dromochorus appear to have a 2-year life cycle, based on observations of D. pruininus (Herrmann & Duran, unpublished). Adult beetles are terrestrial predators of small invertebrates, and are generally believed to be crepuscular or active in the late afternoon, but we have found them at all hours of the day in more shaded microhabitats or when significant cloud cover is present. Dromochorus are extremely fast runners and may evade capture by darting into dense grasses, or in some species, hiding in cracks in the earth, especially D. belfragei and D. pruininus. Larvae are poorly known, and were only recently described (Spomer, Nabity & Brust, 2008). There are remarkably few specimens of these beetles in major museum collections, even though several species occur near major cities and universities in Texas and Oklahoma. Many species records are based on one or a few specimens, and as such, Dromochorus were reported to be rare, or at low densities. This is likely a consequence of their atypical natural history compared to other diurnal North American tiger beetles, and the fact that their habitats are not as commonly visited by collectors. We have found that Dromochorus can be remarkably abundant in the appropriate habitat during the ideal time of year, rivalling or exceeding densities observed in some common riparian tiger beetle species. These observations are unlikely to represent unusual population explosions, as we have witnessed similarly large numbers of beetles every year in areas that we visited each year between 2012 and 2016. KEY TO THE GENUS DROMOCHORUS 1a. Labial palps at least partly yellow to dark amber, with contrasting darker apical segment (Fig. 7A, B)......................................................................................................................................................2 1b. Labial palps consistently dark brown to black throughout (Fig. 7C)..........................................................4 2a. Elytral surface smooth and finely frosted in texture, without any pitting or subsutural foveae. Dorsum with strong blue to violet reflections throughout. Labial palps yellow, with contrasting darker apical seg- ment. Kansas and western Missouri, south to Central Texas.................................................. D. pruininus 2b. Elytra surface dull, textured with fine to deep pitting throughout. Distinct shallow pits running along elytra suture (subsutural foveae, Fig. 8A) may be present..........................................................................3 3a. Dorsum dark brown with prominent shallow subsutural foveae and irregular pitting throughout ely- tral surface. Foveae and smaller pits with metallic green reflections. Irregular green marbling may be present on elytra, head and pronotum. Labial palps yellow, with contrasting darker apical segment. Louisiana to East Texas.................................................................................................................... D. pilatei 3b. Dorsum black with shallow to deep pitting on elytral surface. Some metallic blue reflections may be pre- sent, especially on the supraorbital region of the head and humeral area of the elytra. Subsutural foveae may be present. Labial palps yellow to dark amber, with apical segment darkest. Oklahoma and Texas panhandle, south to East Central Texas...................................................................................... D. belfragei 4a. Elytral surface rough, with shallow to deep pitting. Subsutural foveae present (Fig. 8A), often with metallic green or blue reflections in pits. ‘Hill Country’ region of Central Texas........... D. knisleyi sp. nov. 4b. Elytral surface smooth, often with velvety or frosted texture. No subsutural foveae present (Fig. 8B)..........................................................................................................................................................5 5a. Pronotum glabrous or with few scattered long thin erect setae irregularly placed, rarely concentrated along margins.................................................................................................................................................6 5b. Pronotum with sparse to regular white decumbent setae, mostly in lateral third....................................7 6a. Dorsum finely velvety black, with strong violet, blue or green reflections, especially along margins. Male labrum entirely dark or very nearly so. Body form gracile. South Texas, coastal areas south of Corpus Christi and inland to vicinity of Dimmit County................................................................. D. velutinigrens 6b. Elytra dark ash-grey, sometimes with frosty blue reflections. South Texas in mesquite chaparral forest. Known only from Bexar, Frio and Atascosa Counties.................................................... D. minimus sp. nov. 7a. Elytra dull black, may have bluish reflections especially near margins. South Texas to Mexico, in mes- quite chaparral. Known from Dimmit, LaSalle, and Webb Counties in Texas, and the state of Tamaulipas, Mexico..................................................................................................................... D. chaparralensis sp. nov. 7b. Elytra finely velvety black, may have a faint dark blue sheen. Found in coastal prairie habitat near Gulf of Mexico...................................................................................................................... D. welderensis sp. nov.Published as part of Duran, Daniel P., Herrmann, David P., Roman, Stephen J., Gwiazdowski, Rodger A., Drummond, Jennifer A., Hood, Glen R. & Egan, Scott P., 2019, Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery, pp. 250-285 in Zoological Journal of the Linnean Society 186 on pages 263-265, DOI: 10.1093/zoolinnean/zly035, http://zenodo.org/record/308923

Dromochorus welderensis Duran & Herrmann & Roman & Gwiazdowski & Drummond & Hood & Egan 2019

<p> <i>DROMOCHORUS WELDERENSIS</i> DURAN, HERRMANN, ROMAN & EGAN <b>SP. NOV.</b></p> <p>(FIGS 8B, 9F)</p> <i>Common name</i> <p>Gulf prairie tiger beetle.</p> <i>Type locality</i> <p>Welder Wildlife Foundation, Sinton, TX. Holotype (deposited in NMNH): 1 ♂, Texas: San Patricio Co. / Welder Wildlife Foundation / 11-June-2013 /Coll: A. Mitchell. Paratypes: 18 ♂♂, 15 ♀♀, Texas: San Patricio Co./Welder Wildlife Foundation/11-June-2013/ Coll: A. Mitchell. 2 ♂, 2 ♀, Texas/Buckeye - Matagorda Co./6-8-17 // J.D. Mitchell collector (NMNH). 2 ♀, Texas: San Patricio Co./Sinton/14-V-1966 // leg. W.T. Murray (JSC). 2 ♂, Texas, Victoria/VI-2–06 // C.R. Jones collector. 1 ♀, Texas: Dickinson/May 29 // TAMU-ENTO X0898573 (TAMUIC).</p> <p>1 ♂, 1 ♀, Texas: Bee Co./Pettus/10.V.1964 // Leg. Pryor (SFASU). 4 ♂, 1 ♀, Texas: Nueces Co./Luetgens Coll. (AMNH). 1 ♀, Texas: Corpus Christi/VI-7-1969/ C.W. Griffin // Nueces River Park (NMNH).</p> <i>Distribution</i> <p>Found in the Gulf Prairie ecoregion of coastal Texas, from Houston area to Corpus Christi area.</p> <i>Diagnosis</i> <p> <i>Dromochorus welderensis</i> is diagnosable by having a black dorsum, often with a faint dark-blue sheen, and no pitting, subsutural foveae or infuscations, in conjunction with all dark maxillary palps and a pronotum with decumbent white setae.</p> <p> This species is most likely to be confused with <i>D. chaparralensis</i>, <i>belfragei</i>, <i>velutinigrens</i> or <i>minimus</i>.</p> <p> <i>Dromochorus chaparralensis</i> may be nearly indistinguishable from <i>D. welderensis</i> morphologically, but is ecologically differentiated. The habitat of <i>D. chaparralensis</i> is forested mesquite-chaparral, unlike the Gulf prairie habitat of <i>D. welderensis</i>.</p> <p> <i>Dromochorus belfragei</i> possesses regular pits on the elytra and often subsutural foveae. Maxillary palpi have a contrasting dark apical segment, with other segments dark yellow-testaceous to dark red-testaceous.</p> <p> <i>Dromochorus velutinigrens</i> has a very prominent green, blue, or violet dorsal sheen. The body is substantially more narrow and gracile, especially in males. Male <i>D. velutinigrens</i> have an all dark labrum, whereas <i>D. welderensis</i> males possess a pale central spot. <i>Dromochorus velutinigrens</i> have few to no setae on disk of pronotum.</p> <p> <i>Dromochorus mimimus</i> is generally smaller (Fig. 6; Table 2), and possesses sparse, thin, erect setae on the pronotum. This species also occurs further inland in forested mesquite-chaparral, unlike the Gulf Prairie grassland habitat of <i>D. welderensis</i>.</p> <i>Description</i> <p> Medium to large-sized <i>Dromochorus</i>. Body length 10.9– 14.7 mm, mean ♀ 13.7 mm, mean ♂ 12.6 mm. Head slightly wider than pronotum. <b>Head charcoal brownblack with metallic green, green-blue, or bronze</b></p> <p> <b>reflections mostly limited to the lateral ridge of the supraorbital region</b>. Fine to marked rugosity often present on the frons and vertex. All head portions glabrous except for two supraorbital setae next to each eye. Frons concave in median area, especially in male, bulging towards slightly convex near anterior margin, clearly delimited from clypeus, gradually blending into vertex. Genae black often with metallic green to violet reflections, with shallow longitudinal striae gradually ending at border of vertex. Clypeus black, with metallic violet to green-coloured reflections. Male labrum tridentate with 6–8 setae, central area pale ochre-testaceous, with a thin, dark-brown to black border posteriorly and sometimes anteriorly, dark-brown to black laterally; in some populations, the pale central area of the labrum may exist as a small spot, up to one-quarter of the total labrum surface; female labrum tridentate with 6–8 setae, entirely dark-brown to black with polished metallic cupreous to green reflections. <b>All segments of maxillary and labial palpi consistently darkbrown; apical segment is not darker than other segments</b>. Antennae normal length, reaching back to humerus and basal third of elytron, slightly longer in male than female; scape dark testaceous to black with metallic reflections of violet, cupreous and green, with 2–3 apical setae; pedicel dark testaceous with metallic reflections of violet, cupreous and green, lacking any setae; flagellum dark testaceous, antennomeres 3–4 with metallic violet and green reflections, densely clothed in short white setae, antennomeres 5–11 dulltextured without metallic reflections and possessing erect setae in apical rings only, covered with fine pubescence throughout.</p> <p> <i>Thorax</i>: Pronotum 2.6–3.3 mm in length, mean ♀ 3.1 mm, mean ♂ 2.9 mm; width 2.7–3.4 mm, mean ♀ 3.2 mm, mean ♂ 2.9 mm. Pronotum charcoal brown to black, slightly wider than long, widest near anterior margin, width to length ratio 0.9 to 1.1, setae sparse to regular, mostly present along lateral third of dorsal surface; disc finely rugose, with thin but distinct median line, with well-defined shallow sulci present anteriorly and posteriorly; notopleural sutures clearly defined, not visible from dorsal view; proepisternum black, with metallic violet reflections, glabrous. Elytra elongate, dorsal surface convex, 6.3–8.6 mm length, mean ♀ 8.1 mm, mean ♂ 7.4 mm, shape similar in both sexes, but slightly wider in female, especially toward apical third; sutural spine absent, microserrations not present on elytral apices; <b>elytral texture dull, with no pitting present, elytral coloration charcoal brown to black, often with faint blue reflections throughout elytral surface</b>; elytral maculations absent; subsutural foveae absent.</p> <p> <i>Legs</i>: Pro-, meso- and metacoxae brown to black, with metallic violet to blue reflections, numerous setae on pro- and mesocoxae, sparse on metacoxae; pro- and mesotrochanters with a single erect seta, metatrochanter glabrous, trochanters dark brown-testaceous; femora black with metallic violet reflections, densely clothed in decumbent white setae; tibiae brown, clothed with setae of two types: sparser brown-testaceous long setae and dense, short, decumbent white setae; two tibial spines present; tarsi brown-testaceous, first three dilated protarsomeres in male with dense greyish-white setal pad.</p> <p> <i>Abdomen</i>: Venter mostly black with metallic olive green and violet reflections. Decumbent setae present on ventrite 1. Ventrites 2–6 have sparse, short, brown erect setae present throughout, but often abraded.</p> <i>Etymology</i> <p>Named for the type locality,WelderWildlife Foundation, in Sinton, Texas, as well as the Foundation’s namesake, Robert H. Welder, who established the foundation with the mission to conduct research and education in wildlife management and conservation.</p> <i>Ecology/natural history</i> <p>Adults have a long activity period, from mid-May through early August (A. Mitchell, pers. comm.).</p> <p> <i>Dromochorus welderensis</i> occurs in the Gulf Prairie ecoregion of the Coastal Plain physiographic province of Texas. This <i>Dromochorus</i> is the least associated with tree cover, and <i>D. welderensis</i> is consistently found in tall grasses in upland prairie habitat. Beetles are often found near heavy clayloam or clay banks and hills.</p> <p> This shade-loving species can be observed in early cool mornings or early evenings, and will try to avoid more open areas on hot, clear days. Even when active, adults are particularly reclusive and tend to stay hidden in tall grasses. They are more reluctant to forage in wide open loam areas, in contrast to <i>D. pruininus</i> and <i>D. velutinigrens</i>. Beetles can also be found on thick grass mats as they forage, mate or disperse. When disturbed, they use these dead grass mats as cover.</p>Published as part of <i>Duran, Daniel P., Herrmann, David P., Roman, Stephen J., Gwiazdowski, Rodger A., Drummond, Jennifer A., Hood, Glen R. & Egan, Scott P., 2019, Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery, pp. 250-285 in Zoological Journal of the Linnean Society 186</i> on pages 275-276, DOI: 10.1093/zoolinnean/zly035, <a href="http://zenodo.org/record/3089237">http://zenodo.org/record/3089237</a&gt

Dromochorus minimus Duran & Herrmann & Roman & Gwiazdowski & Drummond & Hood & Egan 2019

<i>DROMOCHORUS MINIMUS</i> DURAN, ROMAN, HERRMANN & EGAN SP. NOV. <p>(FIG. 9D)</p> <i>Common name</i> <p>Pygmy dromo tiger beetle.</p> <i>Type locality</i> <p> SE of Pleasanton, TX. Holotype (deposited in U S N M): 1 ♂, U S A: Te x a s: A t a s c o s a C o./S E o f Pleasanton / 19-VI-2014 /leg D. Duran. Paratypes: 3 ♂ ♂, 3 ♀ ♀, U S A: Te x a s: A t a s c o s a C o./S E o f Pleasanton/19-VI-2014/leg D. Duran. 3 ♂, 4 ♀♀, USA: Texas: Atascosa Co./SE. of Pleasanton/30-V- 2014 <b>/</b> leg D. Sunberg. 1 ♂, 1 ♀, USA: Texas: Atascosa Co./SE. of Pleasanton/02-VI-2015/leg S.J. Roman. 17 ♂♂, 7 ♀♀, USA: Texas: Atascosa Co./SE. of Pleasanton/29-VI-2014/leg D. Brzoska. 1 ♂, USA, Texas: Bexar Co./7 miles S. San Antonio/06-VI-2010/ leg G. Waldren. 1 ♂, USA: Texas: Bexar Co./Loop 1604 Hwy/12-VI-2016/leg J. Back.</p> <i>Distribution</i> <p>Central/south Texas, south of the Balcones Escarpment. Currently known only from Bexar, Atascosa and Frio Counties.</p> <i>Diagnosis</i> <p> <i>Dromochorus minimus</i> can be separated from all other species, by the presence of a frosted or ashy grey to beige dorsum, sometimes with blue reflections, in conjunction with labial palpi that are all dark (apical segment is not darker than other segments), and sparse erect setae on the pronotum, often irregularly placed throughout.</p> <p> This species is most likely to be confused with <i>D. pruininus</i>, <i>chaparralensis</i> or <i>welderensis</i>.</p> <p> <i>Dromochorus pruininus</i> is generally larger (Fig. 6; Table 2), has pale maxillary palps with a contrasting dark apical segment and is also separable by geographic range.</p> <p> <i>Dromochorus chaparralensis</i> is usually larger (Fig. 6; Table 2), and lacks any prominent frosted texturing on the dorsal surface. The pronotum of <i>D. chaparralensis</i> has setae more regularly arranged, mostly along lateral third.</p> <p> <i>Dromochorus welderensis</i> is usually larger (Fig. 6; Table 2), and its pronotum has decumbent white setae, mostly along lateral third. The habitat of <i>D. welderensis</i> is Gulf Coast Prairie.</p> <i>Description</i> <p> Small- to medium-sized <i>Dromochorus</i>. Body length 10.5–13.7 mm, mean ♀ 12.7 mm, mean ♂ 11.7 mm. Head slightly wider than pronotum. Head predominantly charcoal black with blue to green reflections mostly concentrated near the anterior margin and edges of the supraorbital region. Fine rugosity often present on the frons and vertex. All head portions glabrous except for two supraorbital setae next to each eye. Frons concave in median area, especially in male, bulging towards slightly convex near anterior margin, clearly delimited from clypeus, gradually blending into vertex. Genae black with bright polished metallic green to violet reflections, with shallow longitudinal striae gradually ending at border of vertex. Clypeus shining black with blue to violet reflections throughout. Male labrum tridentate with 6–8 setae, central area pale ochre-testaceous,</p> <p> with a thin dark-brown to black border posteriorly and sometimes anteriorly, dark-brown to black laterally; in some populations, the pale central area of the labrum may exist as a small spot, up to one-third of the total labrum surface; female labrum tridentate with 6–8 setae, entirely dark brown to black with polished metallic cupreous to green reflections. <b>All segments of maxillary and labial palpi consistently darkbrown; apical segment is not darker than other segments</b>. Antennae normal length, reaching back to humerus and basal third of elytron, slightly longer in male than female; scape dark testaceous to black with metallic reflections of violet, cupreous and green, with 2–3 apical setae; pedicel dark testaceous with metallic reflections of violet, cupreous and green, lacking any setae; flagellum dark testaceous, antennomeres 3–4 with metallic violet and green reflections, densely clothed in short white setae, antennomeres 5–11 dull-textured without metallic reflections and possessing erect setae in apical rings only, covered with fine pubescence throughout.</p> <p> <i>Thorax</i>: Pronotum 2.4–3.1 mm in length, mean ♀ 2.8 mm, mean ♂ 2.7 mm; width 2.5–3.3 mm, mean ♀ 3.0 mm, mean ♂ 2.7 mm. Pronotum charcoal black, typically with frosty pale grey to brown, or blue to violet sheen, especially along lateral margins, slightly wider than long, widest near anterior margin, width to length ratio 1.0 to 1.1, <b>thin erect setae sparse to irregularly spaced on pronotum</b>; disc finely rugose, with thin but distinct median line, with well-defined shallow sulci present anteriorly and posteriorly; notopleural sutures clearly defined, not visible from dorsal view; proepisternum black with iridescent olive green to violet reflections, glabrous. Elytra elongate, dorsal surface convex, 6.4–8.0 mm length, mean ♀ 7.6 mm, mean ♂ 7.1 mm, shape similar in both sexes, but slightly wider in female, especially toward apical third; sutural spine absent, microserrations not present on elytral apices; elytral texture dull, with no pitting present, <b>elytral coloration charcoal black, typically with grey, brown or blue-grey frosted texture along lateral margins, apex with blue or grey frosted texture</b>; elytral maculations absent; <b>subsutural foveae absent</b>.</p> <p> <i>Legs</i>: Pro-, meso- and metacoxae dark brown with iridescent violet and cupreous reflections, numerous setae on pro- and mesocoxae, sparse on metacoxae; pro- and mesotrochanters with a single erect seta, metatrochanter glabrous, trochanters dark brown-testaceous; femora black with metallic violet and green reflections, densely clothed in decumbent white setae; tibiae testaceous brown, clothed with setae of two types: sparser brown-testaceous long setae and dense short decumbent white setae; two tibial spines present; tarsi brown-testaceous, first three dilated protarsomeres in male with dense greyish-white setal pad.</p> <p> <i>Abdomen</i>: Venter black with metallic olive green and violet reflections. Decumbent white setae present on ventrite 1. Ventrites 2–6 have sparse short brown erect setae present throughout, but often abraded.</p> <i>Etymology</i> <p> <i>Dromochorus minimus</i> is named for its smaller size. On average, this species is the smallest in the genus (Table 2).</p> <i>Ecology/natural history</i> <p>Little is known about this species’ natural history. Adults have been collected from mid-May until late June, but it is possible that the species may be active outside of this window.</p> <p> <i>Dromochorus minimus</i> occurs in mesquite-chaparral savannah in central/south Texas, just south of the Edwards Plateau, part of the larger Gulf Coastal Plains physiographic province. It has been found in open grassy areas interspersed between mesquite trees and clumps of <i>Opuntia</i> cactus. Adult beetles may be found venturing into the open spaces between clumps of grass, and will rapidly run into vegetation if pursued. <i>Dromochorus minimus</i> appears to be remarkably swift, even compared to other species of <i>Dromochorus</i>.</p> <p>In direct sunlight, live specimens appear beige-grey to smoky blue-grey.</p>Published as part of <i>Duran, Daniel P., Herrmann, David P., Roman, Stephen J., Gwiazdowski, Rodger A., Drummond, Jennifer A., Hood, Glen R. & Egan, Scott P., 2019, Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery, pp. 250-285 in Zoological Journal of the Linnean Society 186</i> on pages 272-274, DOI: 10.1093/zoolinnean/zly035, <a href="http://zenodo.org/record/3089237">http://zenodo.org/record/3089237</a&gt