First report of the Euconnus Thomson subgenusCladoconnus Reitter in the New World, represented by thirteen new Appalachian species (Coleoptera, Staphylinidae, Scydmaeninae)

Michael S. Caterino

doi:10.3897/zookeys.1137.97068

Monograph

First report of the Euconnus Thomson subgenus Cladoconnus Reitter in the New World, represented by thirteen new Appalachian species (Coleoptera, Staphylinidae, Scydmaeninae)

Michael S. Caterino^‡

‡ Clemson University, Clemson, United States of America

Corresponding author: Michael S. Caterino ( mcateri@clemson.edu )

Academic editor: Jan Klimaszewski

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: Caterino MS (2022) First report of the Euconnus Thomson subgenus Cladoconnus Reitter in the New World, represented by thirteen new Appalachian species (Coleoptera, Staphylinidae, Scydmaeninae). ZooKeys 1137: 133-175. https://doi.org/10.3897/zookeys.1137.97068

ZooBank: urn:lsid:zoobank.org:pub:DFA4D0BD-CBA6-49D4-87AC-C741E6C216E9

Abstract

Thirteen new species of Euconnus Thomson (Staphylinidae: Scydmaeninae: Glandulariini) are described from the southern Appalachian Mts, USA: Euconnus megalops sp. nov., E. vexillus sp. nov., E. cumberlandus sp. nov., E. vetustus sp. nov., E. adversus sp. nov., E. astrus sp. nov., E. cultellus sp. nov., E. falcatus sp. nov., E. cataloochee sp. nov., E. kilmeri sp. nov., E. draco sp. nov., E. tusquitee sp. nov., and E. attritus sp. nov. These share a number of morphological characters with the Old World subgenus Cladoconnus Reitter, representing a diversification of species distinct from anything previously known from the western hemisphere. Most of the species occur at higher elevations, some at the tops of the region’s highest mountains, and a few are single-peak endemics. No females of these species are winged, and in several species neither sex is winged. A preliminary phylogeny suggests the wingless species represent a clade within a clade of wing-dimorphic species.

Keywords

Biodiversity, dark taxa, leaf litter, metabarcoding

Introduction

Following a century of near neglect, the hyperdiverse scydmaenine (Staphylinidae) genus Euconnus Thomson has seen something of a resurgence of interest. With over 2500 described species, the genus ranks as one of the most species-rich genera of organisms on the planet. Pawel Jałoszyński (2012 and others) has recently attempted to bring some order to the classification of these species on a global scale, revising the types of most of the 30+ subgenera, elevating, synonymizing, or validating the species of most, motivated by and also acknowledging the fact that many hundreds of undescribed species exist, many of uncertain placement in the cumbersome and inconsistent intrageneric taxonomy.

On the North American front, Stephan et al. (2021) recently revised the ‘then’-valid subgenus Napochus, describing and redescribing more than 100 species in the group. Jałoszyński’s (2021) subgeneric revision subsequently demoted Napochus to synonymy with the nominate Euconnus s. str., finding no consistent characters to distinguish them. Synonymizing the monotypic Pycnophus in the same paper, following several other changes (e.g. Jałoszyński 2017) leaves Euconnus with only three valid subgenera in the Nearctic, Psomophus Casey, Tetramelus Motschulsky, and Euconnus s. str., compared with 10 subgenera recognized in American Beetles (O’Keefe 2001). Apart from those formerly contained in Napochus, none of these has been revised since the foundational treatment of Casey (1897), with few species even having been described in the interim.

Recent work in the higher parts of the southern Appalachian mountains of the southeastern USA revealed numerous new Euconnus species. This on its own was not particularly surprising, but the difficulty of assigning all of them to subgenus was. Several of these species exhibit a sexual dimorphism that turns out to be known from only a single subgenus, Cladoconnus Reitter, hitherto known only from the Palaearctic region (Hlaváč and Stevanović 2013; Jałoszyński 2018), the males having longitudinal carinae on the inner edges of the 8^th and 9^th antennomeres. Careful comparison of these species with the other defining characters of the group in Jałoszyński (2018, 2019) suggest that this subgenus is, in fact a member of the North American fauna.

The subgenus Cladoconnus comprises thirty-seven extant species distributed predominantly in the Western Palaearctic region (although recent discoveries by Hoshina and colleagues (Hoshina 2004; Hoshina et al. 2018; Hoshina and Park 2020) suggest that the east Asian diversity is considerable as well) and one fossil species from ~ 40 MY Baltic amber (Jałoszyński and Perkovsky 2021). Here I report this subgenus for the first time from the western hemisphere, represented by 13 previously undescribed species. At the same time, these species require a redefinition of the subgenus, because they exhibit considerable variability in morphology, notably not all having the most conspicuous defining character of the subgenus, the carinae of the male 8^th and 9^th antennomeres.

This group also has significance from a regional, faunistic perspective, as it seems to represent a wholly undocumented high Appalachian radiation. Such endemic radiations are known in numerous other taxa, both arthropods (Barr 1979; Gusarov 2002; Miller and Wheeler 2005; Wheeler and Miller 2005) and other organisms. Cladoconnus are somewhat unusual among even these, however, in having no other close relatives (at least as far as currently documented) elsewhere in North America. Other regional species of Euconnus sensu stricto (where these species might otherwise have keyed out, in e.g., O’Keefe 2001) do not appear to be closely related, most in the southeastern US exhibiting a distinct suite of sexual dimorphisms, particularly on the male abdominal ventrites. On a regional scale, these separate lineages show no geographical overlap, with Euconnus s. str. records coming mainly from low-lying areas in the coastal plain. Most records of the species assigned to Cladoconnus are from ~ 1000 m or above, and some subgroups primarily above 1500 m in the highly restricted spruce-fir habitats of the highest peaks.

In addition to describing these species, I report COI barcode sequences for most of them, several being represented by sequences from multiple localities, allowing a preliminary assessment of their internal phylogenetic relationships, as well as an even more preliminary exploration of their possible relationships among Euconnus species on a broader scale.

Materials and methods

Specimens used in this paper originated in or are deposited in the following collections:

AMNH The American Museum of Natural History, New York;

FMNH The Field Museum, Chicago;

CNCI The Canadian National Collection of Insects, Ottawa;

CUAC The Clemson University Arthropod Collection, Clemson;

UNHC The University of New Hampshire Collection, Durham.

Most of the 679 specimens used in this study were collected as part of a larger inventory of leaf litter inhabiting arthropods. Litter samples were obtained from numerous high elevation localities (> 3300 ft or 1000 m) across five states (Virginia, North Carolina, Tennessee, South Carolina, Georgia) during the years 2015–2021, visiting most sites on two different dates, roughly in spring and fall timeframes, and collecting at least three separate litter samples on each visit. Many of the highest elevation samples come from spruce-fir forest, where litter consists of deep decomposing needles, with minor components of deciduous leaves and fine woody debris. But at lower sites, deciduous leaf litter or Rhododendron litters were often sampled. Litter was sifted down to the soil surface (or to a depth where litter was so decayed as to be indistinguishable from soil, where the interface was not a hard boundary), over an area of ca. 1 m², through an 8-mm mesh, until a bag of ~ 6 L was filled. Samples were processed in the lab using Berlese-Tullgren funnels, running subsamples until thoroughly dry, ~ 12 hours per batch. Specimens were collected directly into 100% ethanol, and moved to -20 °C storage after each subsample was complete.

Conventions

Despite availability of many more specimens of most species, type series are generally restricted to single localities, acknowledging the possibility of cryptic diversity within some of these species. Type specimens are all dissected males or specimens that we’ve been able to associate with dissected males through DNA sequences. Label data for primary and secondary types are quoted; data for non-type specimens are summarized. Full specimen-level data for all material examined, along with voucher codes, extraction codes, and GenBank accession numbers are detailed in an Excel supplement.

Following Hlavác and Stevanović (2013), measurements conform with the following conventions:

BL – total body length is a sum of the lengths of head (anterior labral margin to summit of vertex), pronotum and elytra measured separately;
HW – width of head is measured across eyes;
PW & PL – pronotal width and length are the maximum widths and lengths;
EW – elytral width is the maximum width;
EL – length of elytra along suture.

Sequencing

Many specimens reported here were processed through a voucher-based high-throughput sequencing protocol in an attempt to generate a barcode database for the high Appalachian litter arthropod fauna. Subsequently, I also selected additional specimens, many dry, from older collections to complement these, representing additional localities and potential species. Most barcoded specimens were imaged prior to extraction, with images archived on a Flickr page: https://www.flickr.com/search/?user_id=183480085%40N02&text=Cladoconnus. The supplementary specimens were not imaged, but other sequencing procedures were similar. Dry specimens were removed from points by soaking in 100% ethanol. Every specimen was subdivided or punctured to permit tissue digestion, and placed in a separate well in a 96-well plate. Tissues were digested with lysis buffer and proteinase K (Omega BioTek, Norcross, GA). The liquid fraction was removed to a new plate, leaving behind the voucher remains for further dissection and archiving. Following digestion, remains of extracted specimens were recombined with any non-extracted body parts, labelled, assigned unique CUAC (Clemson University Arthropod Collection) identifiers, and curated into the CUAC. The digested tissue mixture was purified using Omega BioTek’s MagBind HDQ Blood and Tissue kit on a Hamilton Microlab Star automated liquid handling system, eluting with 150 μL elution buffer.

Analyses reported here include sequences from two separate sequencing approaches, both based on a ‘mini-barcode’, a 421 bp fragment of the mitochondrial COI gene amplified using the primers BF2-BR2 (GCHCCHGAYATRGCHTTYCC & TCDGGRTGNCCRAARAAYCA, respectively; Elbrecht and Leese 2017), corresponding to the downstream two-thirds of the standard barcoding region. Primer pairs for each well were tagged with a unique combination of forward and reverse 9 bp indexes to allow multiplexing, synthesized as part of the primer by Eurofins Genomics (Louisville, KY). These indexes were derived from a list provided by Meier et al. (2016). All PCRs were conducted in 12.5 μL volumes (5.6 μL water, 1.25 μL Taq buffer, 1.25 μL dNTP mix [2.5 mM each], 0.4 μL MgCl [50 mM], 1.5 μL each primer, 0.05–0.09 μL Platinum Taq polymerase, 1–2 μL DNA template, with a 95 °C initial denaturation for 5 minutes, followed by 35–45 cycles of 94 °C (30 sec), 50 °C (30 sec), 72 °C (30 sec), and a 5 minute 72 °C final extension on an Eppendorf Gradient Mastercycler.

Earlier barcodes (pre-2022) were generated on an Illumina MiSeq, later ones on an Oxford Nanopore MinION sequencer. For Illumina library preparation, PCR products were combined and purified using Omega Bio-Tek’s Mag-Bind Total Pure NGS Kit, in a ratio of 0.7:1 (enriching for fragments >300 bp). Illumina adapters and sequencing primers were ligated to PCR products using New England BioLab’s Blunt/TA Ligase Master Mix. The amplicon+adapter library was again purified using Mag-Bind Total Pure NGS, and quantified using a Qubit fluorometer. This library was sequenced on an Illumina MiSeq using a v.3 2×300 paired-end kit. Nanopore libraries were prepared using the ligation sequencing kit LSK-112 (Oxford Nanopore Technologies, Oxford, UK) and sequenced using a v10.4 flowcell.

Illumina reads were processed with bbtools software package (https://jgi.doe.gov/data-and-tools/bbtools/; v38.87, Bushnell et al. 2017) to merge paired read ends, remove PhiX reads, trim Illumina adapters, filter reads for the correct size, remove reads with quality score<30, cluster sequences by similarity allowing 5 mismatches (~1%), and generate a final matrix in FASTA format. Nanopore reads were basecalled using the ‘super-accurate’ algorithm of Guppy (v6.1.2), then demultiplexed using ONTbarcoder v0.1.9 (Srivathsan et al. 2021), with minimum coverage set at 5. Final barcode sequences were submitted to GenBank, under accession numbers OP779401–OP779518 (see Suppl. material 1 for details).

Phylogeny

FASTA files from all sequencing methods were combined and aligned with the online version of Mafft v7 (Katoh et al. 2017) using the ‘auto’ strategy. To attempt to determine the placement of putative Appalachian Cladoconnus species among global Euconnus diversity, sequences were combined with other barcode-region sequences for Euconnus available on BOLD and GenBank, making a combined matrix of 389 sequences. These include 117 American putative Cladoconnus, two European Cladoconnus, 265 other Euconnus sequences (multiple individuals for many species, as well as many unidentified) representing other subgenera (Neonapochus, Tetramelus, Napochus, and Euconnus s. str., Old World and New), and five outgroups from the also-Glandulariini genus Brachycepsis Brendel. Phylogenetic reconstructions were performed using maximum likelihood (ML) with W-IQ-TREE v. 2.0 (Trifinopoulos et al. 2016), available at http://iqtree.cibiv.univie.ac.at. This program was used also to determine the best substitution model for the data. Analyses used a perturbation strength of 0.4. and an IQ-TREE stopping rule value at 200. Branch support is based on an ultrafast bootstrap analysis (Minh et al. 2013), run with 1,000 bootstrap replicates with a minimum correlation coefficient of 0.99.

Results

Taxonomy

Genus Euconnus Thomson, 1859

Subgenus Cladoconnus Reitter, 1909

Cladoconnus Reitter, 1909: 226, as subgenus of Euconnus Thomson. Type species: Scydmaenus motschulskii Motschulsky, 1837 (subsequent designation by Newton and Franz 1998: 145).

Euconnus (Cladoconnus) Reitter: Hlavác and Stevanović 2013 (diagnosis); Jałoszyński 2018 (diagnosis).

Diagnosis

Previous diagnoses of Palaearctic Cladoconnus have focused primarily on the presence in males of serrulate carinae on the inner margins of antennomeres VIII and IX, a character not known elsewhere in Euconnus. Jałoszyński (2018) further noted the unique presence of a bell-shaped, setose pronotum with 3 basal foveae in an inward-pointing triangular arrangement on each side of a short median basal pronotal carina, straddling short sublateral carinae. He also noted a unique mandibular shape in which the outer margin is interrupted where the apical portion narrows abruptly. The species described here do not entirely conform to this diagnosis, showing variability in most of these characters among them. All are small, with total body lengths ranging from 1.3 to 1.7 mm, not differing much between the sexes (Table 1). The highly distinctive male antennal carinae are evident in most of these species (Figs 4E, 6, 9E, 14C, 16C), but are completely absent in a couple that otherwise seem to be related by other morphological characters and by DNA sequences (Figs 1E, 8A, 13E). Most are consistent in having a bell-shaped pronotum, narrowed basally in some, with the triangle pattern of posterior foveae and at least short sublateral carinae (Figs 4F, 9F). A median basal pronotal carina is evident in several (e.g., Fig. 4F), but in others it is so weak as to be essentially absent (e.g., Fig. 9F). Only one species (E. vetustus) exhibits the distinctive bi-arcuate mandible, the others appearing to have simply arcuate mandibles. Similar to all Palaearctic species, American Cladoconnus have male genitalia with complex, asymmetrical endophallic armature. Metathoracic wings have not been described for European species, but illustrations and descriptions of body and metathoracic shape suggest that most described species are fully winged in both sexes. Hoshina et al. (2018) notes apparent sexual dimorphism in wingedness in three Asian species. Several of the new American species are flightless in both sexes, and some appear to be flightless in females only. Females associated by sequencing show reduced eyes relative to males, and have smaller, unmodified antennomeres, in several species having the club reduced to only three antennomeres (e.g., Fig. 9D). Due to this variability, it is likely that future revision of Cladoconnus will be necessary, but for now these new species seem to have clear relationships to those in the Old World, and are relatively easy to recognize among New World Euconnus.

Table 1.

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XLSX

Measurements of E. (Cladoconnus) species, in mm. Each cell has separate averages for males / females, with total number measured in the last column.

	HL	HW	PL	PW	EL	EW	BL	n
E. megalops	0.4/0.4	0.3/0.3	0.4/0.4	0.3/0.4	0.9/0.9	0.6/0.6	1.7/1.7	3 / 3
E. falcatus	0.3/0.3	0.2/0.2	0.3/0.3	0.3/0.3	0.7/0.7	0.5/0.5	1.3/1.3	3 / 3
E. cataloochee	0.3/0.3	0.2/0.2	0.3/0.3	0.3/0.3	0.7/0.7	0.5/0.5	1.4/1.3	3 / 3
E. tusquitee	0.3	0.3	0.3	0.3	0.7	0.4	1.3	1 / 0
E. kilmeri	0.3	0.3	0.3	0.3	0.7	0.4	1.3	1 / 0
E. draco	0.3/0.3	0.2/0.2	0.3/0.3	0.3/0.3	0.7/0.7	0.5/0.5	1.3/1.3	3 /2
E. vetustus	0.3/0.4	0.3/0.3	0.3/0.4	0.4/0.4	0.9/0.8	0.6/0.6	1.5/1.5	3 / 3
E. attritus	0.3/0.3	0.3/0.3	0.4/0.4	0.3/0.3	0.8/0.8	0.5/0.5	1.5/1.5	3 / 3
E. astrus	0.4/0.4	0.3/0.3	0.3/0.4	0.3/0.3	0.8/0.9	0.6/0.6	1.5/1.6	3 / 3
E. vexillus	0.4/0.4	0.3/0.3	0.4/0.4	0.4/0.4	0.9/0.9	0.7/0.7	1.7/1.7	3 / 3
E. adversus	0.4/0.4	0.3/0.3	0.4/0.4	0.3/0.4	0.9/0.9	0.6/0.6	1.6/1.6	3 / 3
E. cumberlandus	0.4/0.4	0.3/0.3	0.4/0.4	0.4/0.4	0.9/0.9	0.6/0.6	1.7/1.7	3 / 3
E. cultellus	0.3/0.3	0.3/0.2	0.3/0.3	0.3/0.3	0.7/0.7	0.5/0.5	1.3/1.3	3 / 3

There is little point writing a key to these species because most can only definitely be identified by male genitalia, with a few externally similar species even sympatric in a few places. There are three main morphotypes, dark and stout (Euconnus vexillus and E. vetustus), dark with rufescent highlights, more gracile (Euconnus megalops), and small and pale (flightless), with a mix of modified and non-modified male antennomeres (all remaining species). All share a generally similar form of male genitalia: the basal bulb is large and voluminous, narrowing at the shoulders to a variously tapered median lobe (sensu Stephan et al. 2021; equivalent to the dorsal apical projection of Jałoszyński 2012. The opposite side (morphologically ventral) exhibits a thin, weakly sclerotized compressor plate (sensu Stephan et al. 2021; equivalent to the ventral apical projection of Jałoszyński 2012). They all have a crescent-shaped diaphragm plate sclerite, and relatively thin, weakly curving parameres, bearing a small number of apical setae. They vary much more, however, in the sclerites of the endophallus, which are always asymmetrical, including two or more long, curving, often opposing hooks or spikes. These may bear secondary hook-like processes, or other variously acute projections. In descriptions ‘upper’ and ‘lower’ are used to refer to the diaphragm and foramen sides, respectively, and ‘left’ and ‘right’ referring to the structures as drawn (upper side up), not to true morphological position.

Euconnus (Cladoconnus) megalopssp. nov.

https://zoobank.org/92355F93-458D-455B-B19E-CFE0D3DFE12E

Figs 1, 2A, 3

Type material

Holotype ♂, deposited in FMNH: “USA: NC: Haywood Co., 35.6721°N, 83.1760°W, Smoky Mts NP, 6150’, Big Cataloochee Mt., xi.5.2020, sifted litter, M.Caterino & F.Etzler” / “[QR code] CLEMSON-ENT CUAC000135174” / “Caterino DNA Voucher Extraction MSC6486, Morphosp. BCat.B.316”. Paratypes (33, CUAC, FMNH, CNCI, UNHC) – 3 ♀, 6 ♂: same data as type; 1 ♀, 3 ♂: “USA: NC: Haywood Co., 35.6686°N, 83.1749°W, Smoky Mts NP, 5725’, Big Cataloochee Mt., vii.14.2020, sifted litter, M.Caterino, F.Etzler”; 3 ♀: “USA: NC: Haywood Co., 35.6722°N, 83.1758°W, Smoky Mts NP, 6155’, Big Cataloochee Mt., vii.14.2020, sifted litter, M.Caterino, F.Etzler”; 2 ♀: “USA: NC: Haywood Co., 35.6414°N, 83.1958°W, SmokyMtsNP, Balsam Mt.Tr., 4752’, xi.5.2020, M.Caterino & F.Etzler, Sifted litter”; 3 ♀: “USA: NC: Haywood Co., 35.6425°N, 83.2007°W, SmokyMtsNP, Balsam Mt.Tr., 5167’, xi.5.2020, M.Caterino & F.Etzler, Sifted litter”; 9 ♀, 3 ♂: “USA: NC: Haywood Co., 35.6453°N, 83.2025°W, SmokyMtsNP, Balsam Mt.Tr., 5086’, xi.5.2020, M.Caterino & F.Etzler, Sifted litter”.

Other material

(229 adults, 7 larvae) GA: Rabun Co., Chattahoochee NF, Rabun Cliffs, 4082 ft., 11-May-2021 (7 ♀, 3 ♂); Towns Co., Chattahoochee NF, Brasstown Bald, 4495 ft., 17-Nov-2020 (1 ♀, 1 ♂); NC: Buncombe Co. Co., Pisgah National Forest, Big Butt Trail, 5190 ft., 19-Mar-2016 (1 ♀, 2 ♂); Cherokee Co., Nantahala National Forest, Hickory Branch trail, 4156 ft., 26-Jul-2015 (1 ♀); Clay Co., Nantahala National Forest, Riley Knob, 4330 ft., 11-May-2020 (1 ♀); Clay Co., Nantahala National Forest, Shooting Creek Bald, 4809 ft., 11-May-2020 (1 ♀); Clay Co., Nantahala National Forest, Tusquitee Bald, 4656–5015ft, 1-Sep-2020 (4 ♀, 2 ♂); Clay Co., Nantahala National Forest, Chunky Gal Trail, 4014 ft., 1-Sep-2020 (2 ♀, 1 ♂); Graham Co., Nantahala National Forest, Teyahalee Bald, 4060–4663ft., 12-Apr-2022 (2 ♀, 3 ♂); Graham Co., Nantahala National Forest, Cherohala Skyway – Wright Ck., 4702 ft., 4-May-2020 (2 ♀, 3 ♂); Graham Co., Nantahala National Forest, Huckleberry Knob, 5491–5522 ft., 4-May-2020 & 13-Oct-2020 (10 ♀, 5 ♂); Graham Co., Nantahala National Forest, jct. Indian & Santeetlah Cks., 2770–2833 ft., 24-Jun-2015 (11 ♀, 10 ♂); Graham Co., Nantahala National Forest, Joyce Kilmer Forest, 2696–2942 ft., 20-Jul-2015 (2 ♀, 5 ♂); Haywood Co., Blue Ridge Parkway National Park, Mt. Hardy, 6110 ft., 8-Sep-2020 (9 ♀, 6 ♂); Haywood Co., Pisgah National Forest, Mountains to Sea Trail, 5540 ft., 8-Sep-2020 (1 ♀); Haywood Co., Pisgah National Forest, Black Balsam Knob, 6072 ft., 7-May-2018 (1 ♀); Haywood Co., Blue Ridge Parkway National Park, Richland Balsam Mt., 6207 ft., 11-Sep-2019 (1 ♀); Haywood Co., Blue Ridge Parkway National Park, Pisgah Mt., 5245 ft., 10-Aug-2021 (1 ♀, 1 ♂); Jackson Co., Sumter National Forest, Ellicott Rock Wilderness, Bad Creek trail, 2397 ft., 3-Jun-2015 (1 ♀, 2 ♂); Jackson Co., Nantahala National Forest, Whiteside Mt., 4740 ft., 22-Jun-2022 (1 ♀); Jackson Co., Cashiers, Hwy 64, 3700 ft., 1-Feb-2020 & 16-Feb-2020 (6 ♀, 2 ♂); Jackson Co., Nantahala National Forest, Toxaway Mt., 4770 ft., 5-Aug-2020 (2 ♀, 1 ♂); Jackson Co., Blue Ridge Parkway National Park, along Blue Ridge Pkwy, 5572 ft., 11-Sep-2019 (2 ♀); Jackson Co., Balsam Mountain Preserve, Doubletop Mountain, 4839 ft., 17-Jun-2015 (3 ♀, 2 ♂); Jackson Co., Balsam Mountain Preserve, Sugarloaf Mountain, 4484 ft., 15-Jun-2015 (2 ♀); Jackson Co., Balsam Mountain Preserve, Boar ridge, 4040 ft., 16-Jun-2015 (4 ♀, 1 ♂); Jackson Co., Balsam Mountain Preserve, Dark ridge, 3290 ft., 20-Jun-2015 (2 ♀, 7 ♂); Jackson Co., Blue Ridge Parkway National Park, Waterrock Knob, 6281 ft., 29-May-2018 (1 ♀, 1 ♂); Macon Co., E Highlands, Hwy 64, 3880–3990 ft., 1-Mar-2020 (6 ♀, 2 ♂); Macon Co., Nantahala National Forest, Jones Gap, 4447 ft., 16-Jul-2015 (1 ♀); Macon Co., Nantahala National Forest, Jones Knob, 4237 ft., 28-Jul-2015 (1 ♀); Macon Co., nr. Wayah Bald, 5280 ft., 16-Mar-2016 (2 ♀); Macon Co., Nantahala National Forest, Copper Ridge Bald, 5144 ft., 9-Jul-2019 (1 ♀, 1 ♂); Macon Co., Nantahala National Forest, Cowee Bald, 4839–4942ft., 9-Jul-2019 (5 ♀, 5 ♂); Macon Co., Hwy. 64, nr. Dry Falls, 16-May-1986 (1 ♂); Madison Co., Pisgah National Forest, Camp Creek Bald, 4741 ft., 1-Mar-2022 (1 ♂); McDowell, Pisgah National Forest, Snooks Nose Trail, 2219 ft., 25-Aug-2015 (1 ♀, 2 ♂); Polk, Melrose Falls (lower), 1103 ft., 10-Aug-2021 (1 ♀, 3 ♂); Polk, Green River Game Lands, Lower Bradley Falls Tr., 1620 ft., 19-Mar-2018 (3 ♀, 1 ♂); Polk, Green River Game Lands, Green River Cove Tr., 1070 ft., 18-Mar-2018 (1 ♀); Polk, Green River Game Lands, 1740, 18-Mar-2018 Polk, Green River Game Lands, 1740 ft., 18-Mar-2018 (1 ♀, 1 ♂); Buncombe Co. Co., Blue Ridge Parkway National Park, Bull Gap, 3100 ft., 1-May-1990 (1 ♂); Swain Co., Great Smoky Mountains National Park, Clingmans Dome, 6264–6500 ft., 4-Jun-2018 & 14-Sep-2021 (4 ♂); Swain Co., Great Smoky Mountains National Park, Lakeshore Tr., Payne Ck., 1816 ft., 12-Apr-2022 (1 ♀, 2 ♂); Transylvania Co., Pisgah National Forest, Hwy 215, 1 mi. S. Blue Ridge Pkwy, 5122 ft., 7-May-2018 (1 ♀); Yancey Co., Pisgah National Forest, Woody Ridge Tr., 5086–5301ft., 15-Jun-2020 & 19-Oct-2021 (1 ♀, 2 ♂); SC: Greenville Co., Chestnut Ridge Heritage Preserve, 1090 ft., 8-Apr-2018 (1 ♀); Pickens Co., Eastatoe Creek Heritage Preserve, 1421 ft., 30-Apr-2015 (1 ♂); Pickens Co., Sassafras Mountain summit, 3347 ft., 10-Jun-2015 (1 ♂); Oconee Co., Sumter National Forest, Ellicott Rock Wilderness, 2113–2679 ft., 3-Jun-2015 & 4-May-2015 (5 ♀, 4 ♂); Oconee Co., Sumter National Forest, Riley Moore Falls, 900 ft., 3-Mar-2018 (2 ♀); Oconee Co., Coon Branch Nat. Area, 1950 ft., 28-Feb-2016 (3 ♀, 1 ♂); TN: Unicoi, Cherokee Co. National Forest, Big Bald, 5346–5430 ft., 5-Aug-2020 & 21-May-2021 (5 ♀); Blount Co., Great Smoky Mountains National Park, Whiteoak Sink, 1724 ft., 27-Oct-2021 (1 ♂); Sevier Co., Great Smoky Mountains National Park, Alum Cave Bluff Trail, 5196 ft., 25-Jun-2019 (3 ♀, 1 ♂); Sevier Co., Great Smoky Mountains National Park, Appalachian Trail nr. Newfound Gap, 5456 ft., 4-Jun-2018 (4 ♀, 1 ♂); Sevier Co., Great Smoky Mountains National Park, Off Hwy 441, 4575 ft., 12-Mar-2020 (2 ♀). LARVAE: NC: Swain Co., Great Smoky Mountains National Park, Clingmans Dome, 14-Sep-2021; Haywood Co., Great Smoky Mountains National Park, Big Cataloochee Mt., 5-Nov-2020; Haywood Co., Great Smoky Mountains National Park, Balsam Mt. Trail, 5-Nov-2020; Jackson Co., Blue Ridge Parkway National Park, Browning Knob, 22-Sep-2020; TN: Sevier Co., Great Smoky Mountains National Park, Alum Cave Bluff Tr., 28-Sep-2021; GA: Rabun Co., Chattahoochee NF, Rabun Cliffs, 25-Nov-2019.

Description

Males winged, females lacking fully developed flight wings; large, elongate, generally dark but elytra reddish at humeri and often along elytral suture (Fig. 1C), female generally darker (Fig. 1D); male eyes large, protuberant, with ~ 30 large ommatidia (Fig. 1A, E); female eyes smaller, flush with side of head, comprising ~ 12 ommatidia (Fig. 1B, F); scape and pedicel similar in length, ca. as long as width of eye, antennomeres 3–6 uniformly shorter, ca. as long as wide, male antennomere VII weakly asymmetrical, slightly narrowed anterad, male antennomeres VIII-XI enlarged and elongate (longer than wide) but none carinate on anterior edges (Fig. 1E); female with antennal club tetramerous, antennomeres shorter than width (Fig. 1F). Frons and vertex with long, erect setae, each ca. as long as scape; vertex narrowed to a broadly rounded point; neck ca. one-half maximum head width; frons shallowly depressed between antennal bases; epistoma deeply depressed below antennae; labrum with anterior margin evenly rounded, with comb of short setae at middle. Pronotum densely setose at sides and anteriorly, more sparsely posterad, ‘bell-shaped’, widest just beyond middle, narrowed anterad and posterad, posterior margin slightly widening; pronotum depressed along posterior margin with very short median longitudinal carina and stronger lateral longitudinal carinae, a distinct fovea on either side between these carinae; a weak sublateral carina merging with lateral one at posterior pronotal corner, a distinct fovea between them (apparently the anterior-most of the two shown for E. (C.) motschulskii in Jałoszyński [2018]), and an additional shallow fovea below, on the side; prosternum rather short in front of procoxae, lacking median carina, with dense fringe of setae along anterior margin; elytron sparsely covered with fine setae, with pair of deep foveae at base, longitudinally weakly depressed behind these; elytral apices rounded; mesoscutellar shield hidden; mesoventrite with strong carina, setose along its crest, separating mesocoxae, extending anterad to separate apices of procoxae, posteriorly merging with metaventrite immediately behind mesocoxae; mesepimera densely setose, produced laterad mesocoxa; metacoxae narrowly separated by metaventral process; abdominal ventrites unmodified; legs generally slender, setose; protibia with only weakly expanded adhesive setae along inner margin of apical third. Aedeagus (Fig. 2A) with median lobe broadly truncate, parameres thin, rather short, straight, tapered to apex, each with three or four setae extending to or just beyond apex of median lobe; compressor plate asymmetrical, with apex obliquely truncate to weakly lobed off center; endophallus with asymmetrical armature; upper armature comprising two long curved sclerites, one longer, nearly reaching apex of median lobe at rest, abruptly curved near apex with thin inner blade bridging the apex, its inner edge concave, the other upper sclerite curving opposite, thinner, bluntly rounded at apex; lower armature comprising three separate processes: one basal, short, strongly curved, and with a bifid or trifid apex; one longer, medial, broadly hooked; the third lateral and more slender, elongate, apex acute and variously straight or bending mediad.

Figure 1.

Habitus and character photos of Euconnus megalops A male, lateral view B female, lateral view C male, dorsal view D female, dorsal view (BgBld.B.349) E SEM of male head, lateral F SEM of female head, lateral.

Figure 2.

Aedeagus A Euconnus megalops B Euconnus vexillus C Euconnus cumberlandus D Euconnus vetustus.

Figure 3.

Map of collecting records for Euconnus (Cladoconnus) megalops.

Distribution

This species is the most abundant and widespread of the Appalachian Cladoconnus species, occurring from Brasstown Bald in the southwest, northeast to Celo Knob in the Black Mts. It also exhibits the widest elevational range of the species, from ca. 900 ft in upstate South Carolina, all the way to the top of Clingmans Dome at 6500 ft.

Remarks

This species’ morphology is relatively invariant across its broad range. The upper sclerites of the endophallic armature vary slightly in apical curvature and shape, but without obvious geographic trends. Similarly, none of these variants correspond to a geographically dispersed, divergent genetic subclade within the broader species, a peculiar result that merits further investigation.

This species name refers to the conspicuously enlarged eyes of the males.