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JOHN D. OSWALD Department of Entomology, Texas A&M University, College Station, TX, U.S.A. REVIEW OF THE BROWN LACEWING GENUS BIRAMUS (NEUROPTERA: HEMEROBIIDAE: HEMEROBIINAE), WITH THE DESCRIPTION OF A NEW SPECIES FROM COSTA RICA AND PANAMA Oswald, J. D., 2004. Review of the brown lacewing genus Biramus (Neuroptera: Hemerobi- idae: Hemerobiinae), with the description of a new species from Costa Rica and Panama. – Tijdschrift voor Entomologie 147: 41-48, figs. 1-7. [ISSN 0040-7496]. Published 1 June 2004. The brown lacewing genus Biramus is reviewed and a new species, B. aggregatus, is described. The neotropical range of this genus is extended northwesterly from Venezuela to now include Costa Rica and Panama. The new species is differentiated on the basis of male terminalic char- acters, primarily structures of the ectoproct and gonarcus/mediuncus complex. Synapomor- phies previously identified for the formerly monobasic genus Biramus are reviewed and differ- entiated from autapomorphies now attributable to its two included species. Dr. John D. Oswald, Department of Entomology, Texas A&M University, College Station, TX 77843-2475 USA. E-mail: [email protected] Key Words. – brown lacewings; systematics; taxonomy; Neotropical region The family Hemerobiidae, brown lacewings, is a the conclusion that many of the exceptional morpho- cosmopolitan clade of approximately 600 extant logical features previously identified in Biramus luna- species of small predaceous insects in the order Neu- tus now support the monophyly of the genus Biramus. roptera. The phylogeny, taxonomy, and biogeogra- This result further strengthens the interpretation of phy of the world genera of this family have been Biramus as the sister-group to all other extant hemero- broadly treated by Oswald (1993a, 1993b, 1994). biine brown lacewings. The taxonomic review below The species were last comprehensively catalogued by reassesses the distributions of Biramus character states Monserrat (1990). and represents the first opportunity to distinguish be- The genus Biramus and its single originally includ- tween intraspecific autapomorphic (‘species-level’) ed species B. lunatus were described by Oswald and interspecific synapomorphic (‘genus-level’) traits (1993a) on the basis of eight specimens collected at within this clade. several sites in Venezuela. This new genus proved to be of particular phylogenetic interest as cladistic evi- MATERIALS AND METHODS dence suggested that its type species constituted the sister-group of the relatively speciose subfamily Heme- Abbreviations and Symbols robiinae (sensu Oswald, 1993b), which contains ca. *, in synonymical listings indicates one or more fig- 200 species, or approximately one-third of the species- ures pertaining to the annotation it follows, in de- level diversity of extant brown lacewings. scriptive text indicates a putative synapomorphy of This paper reports the discovery of a second species the relevant taxon; dst, distribution; FT, female termi- of Biramus from Costa Rica and Panama. This finding nalia; MT, male terminalia; OD, original description; extends the known range of the genus northwesterly TAMU, Texas A&M University Insect Collection, Col- into southern North America. The discovery of this lege Station, TX, USA; W, wing; UCV, Universidad new species provides an opportunity to reassess the Central de Venezuela, Maracay, Venezuela; USNM, universality of characters previously identified as joint United States National Museum of Natural History, synapomorphies of Biramus and its single originally Washington, DC, USA. For morphological abbrevia- included species. Investigations in this regard support tions see the caption to figs. 1-7. 41 Downloaded from Brill.com09/29/2021 12:17:21PM via free access T E, 147, 2004 Illustrations ly falcate; marginal trichosores prominent proximally Drawings were prepared with the aid of drawing and distally; proximal humeral trace recurrent and tubes attached to compound and dissecting micro- pectinately branched; costal space broad proximally, scopes. Terminalic figures were drawn from elements narrowed distally; stigmal region distinct; 1 proximal macerated in KOH and stained with Chlorazol Black. Sc-R crossvein present (=1sc-r), crossvein 2sc-r absent (Oswald 1993b:170, character 28); anterior radial Terminology trace bearing only 2 oblique radial branches (no varia- Morphological terminology, particularly for wing tion observed in 22 wings from 11 specimens), distal venation and male and female terminalia, follows that ORB (=ORB2) forked proximal to first fork of proximal of Oswald (1993a, b). ORB (=ORB1); precubital portion of 4th (=outer) gra- date series nearly absent (lost?), limited to crossveins 4m-cu and 4ir1; most wings with a crescentic hyaline Genus Biramus Oswald region located at site of forewing falcation. Biramus Oswald, 1993a: 363. Type species: Biramus lunatus Hind wing (Oswald 1993a: 365, fig. 2). CuP ab- Oswald, 1993, by original designation. sent or vestigial. Etymology: Bi- (< L. bi-, two) + -ramus (< L. ramus [masc.], branch), in reference to the two oblique radial Male terminalia (figs. 1-5). Tergite 9 (fig. 1, 9t): branches of the forewing radius of its type species, see Os- Entire (not divided sagittally), narrow dorsally, broad- wald 1993a: 364. Gender: masculine, from the gender of ened ventrolaterally; posterior margin slightly flared the L. noun ramus, Art. 30.1.1.): Monserrat 2002:238 (dst outward in region of articulation with ectoproct; Ster- [Costa Rica]). nite 9 (9s): prominent, shield-shaped in ventral view, i.e., broad proximally, tapered posteriorly, posterior Diagnosis margin entire; Ectoproct (ect): narrow dorsally; pos- Differentiated from all other hemerobiid genera by teroventral angle produced as a long, slender pos- the following combination of forewing characters (see teroventral lobe (pvl); proximoventral angle giving rise Oswald 1993a: 365, fig. 1b): (1) radius bearing two to a linear depression (area of cuticular weakness), the oblique radial branches [=ORB’s, =’radial-sectors’], (2) ventral cleft (vc), that runs longitudinally onto base of subcosta and anterior radial trace well separated in posteroventral lobe (*); callus cercus (cc) and tri- basal half of wing [closely adjacent in Notiobiella, chobothria present, trichobothrial alveoli rosettiform; pantropical], (3) first (most proximal) fork of ORB1 lo- dorsomedial margin of ectoproct opposite callus cer- cated distal to most proximal fork of ORB2 [the relative cus bearing a small peninsulate lobe (fig. 2, pl) (*), positions of these forks are reversed in most other lobe joined to main body of ectoproct by a narrowed hemerobiid genera with only two ORB’s, e.g., Nomero- isthmus that inserts on ectoproct at posterior end of a bius, Neosympherobius, Psectra, Sympherobius, Zacho- shallow, asetose, furrow that traverses ectoproct above biella], and (4) crossvein linking base of ORB1 to ante- callus cercus; distal margin of peninsulate lobe bearing rior radial trace absent [present in Carobius, Australia]. a densely packed field of specialized (shortened and See also the putative synapomorphies identified in the thickened) setae; adjacent margin of inner process description below by an asterisk (*). (ipe) also bearing a field of specialized (shortened and thickened) setae (*); Gonarcus (fig. 5): intragonarcus Description (igps + ihgs) present, variable in extent; extrahemigo- Medium-sized hemerobiids, forewing length from narcus absent (its structural function replaced by neo- base of tegula to wing apex 6.9—8.5 mm (mean=8.0, hemigonarcus); gonosaccal membrane attached to n=11 wings). hemigonarcus along its inner face at junction of intra- Head. Temporal costae poorly developed; epicra- hemigonarcus (ihgs) and neohemigonarcus (nhgs); ex- nial suture absent; clypeus bearing paired dorsomedi- tragonopons (Oswald 1993a: 365, fig. 6, egps) limited al, dorsolateral, ventromedial, and ventrolateral setae, to a pair of small triangular sclerotized lobes that issue unpaired dorsomedian seta absent; maxillary palp from antextragonarcal commissure and (at least ple- with five primary palpomeres, ultimate (5th) palpo- siomorphically) support proximolateral angles of mere with a small apical subsegment; labial palp with mediuncus; gonofenestra present in region between three primary palpomeres, ultimate (3rd) palpomere extragonopontal lobes and proximal margin of medi- with a small apical subsegment. uncus; mediuncus (med) a slender membrane-mar- Thorax. Some specimens exhibit a pale dorsolongi- gined plate proximally, distally bearing a pair of dis- tudinal vitta extending from head vertex to meso- or similar sagittal teeth; neogonopons (ngps) metascutellum, but this is lacking in other specimens well-developed, overlying extragonopontal lobes (postmortem loss?); pronotum transverse, lateral mar- (when present) and proximal portion of gonofenestra, gins produced as prominent lateral lobes. dorsomedial neogonopontal carina present or absent; Forewing (Oswald 1993a: 365, fig. 1). Very slight- neohemigonarcus well developed but weakly sclero- 42 Downloaded from Brill.com09/29/2021 12:17:21PM via free access O: Review of Biramus tized, neogonarcal commissure often indistinct due to sonal’ forest sites in Venezuela. Adults of B. lunatus gradual transition between sclerotized neogonarcus appear to be present for much of the year in Venezuela and associated paragonosaccal membrane; Parabacu- (the eight known specimens were collected in January, lum (figs. 3-4): parabacular apophysis (pa)