A new suspected paedomorphic genus of net-winged beetles from the Atlantic Rainforest (Coleoptera, Elateroidea, Lycidae)

ARTICLE A new suspected paedomorphic genus of net‑winged beetles from the Atlantic Rainforest (Coleoptera, Elateroidea, Lycidae) Vinicius S. Ferreira¹ & Luiz Felipe Lima Silveira² ¹ Montana State University (MSU), Montana Entomology Collection (MTEC). Bozeman, Montana, United States. ORCID: http://orcid.org/0000-0001-8748-0358. E‑mail: (corresponding author) ² Western Carolina University (WCU), Biology Department. Cullowhee, North Caroline, United States. ORCID: http://orcid.org/0000-0002-0648-3993. E‑mail: Abstract. Lycidae are among the better studied groups in the superfamily Elateroidea, however despite the progress in the taxonomic understanding of the Neotropical fauna, much still remains unknown and undescribed in the region. The description of the new genus Xenolycus gen. nov., from Serra dos Órgãos, a subrange of the Serra do Mar mountain range, in the Atlantic Rainforest in Rio de Janeiro State, Brazil, contributes to the knowledge of the Neotropical Lycidae fauna. The new genus can be distinguished from all other known Calopterini and Neotropical Lycidae by the combination of a pronotum with a wide, deep and strongly visible longitudinal cell in the disc area, the filiform antennae, the dehiscent elytra with reticulation strongly reduced and bearing only two weakly developed elytral costae and the mouthparts partially reduced, with rudimentary, barely visible mandibles. The type species, Xenolycus costae sp. nov., is illustrated and diagnostic characters and a discussion on the tribal placement of the new genus are provided. Key-Words. Leptolycini; Neotropical Region; Neoteny; Elateroidea; Rio de Janeiro. INTRODUCTION When comparing the chaotic situation in the taxonomic knowledge of Elateroidea beetles in the Neotropical region (e.g., Lampyridae with Photinus Laporte, Phengodidae with Cenophengus LeConte, Omethidae with Telegeusis Barber, to mention a few), Lycidae are among the better studied groups in this superfamily. In the past two decades many of the most specious tribes found in the Neotropical region have been reviewed (Calopterini and Platerodini) (Bocakova, 2001, 2005), some genera have been revised (e.g., Bocakova et al., 2012; Ferreira, 2016; Ferreira & Ivie, 2018) and several new taxa described (e.g., Ferreira, 2015, 2016; Kazantsev, 2013, 2017), while several world level phylogenies and classifications have been proposed (Bocak & Bocakova, 2008; Kazantsev, 2013; Masek et al., 2018; Kusy et al., 2019) helping to slowly, but steadily, elucidate the huge gap in taxonomic knowledge in this diverse but still understudied family of beetles. Despite the progress, much still remains unknown and some of the most diverse and abundant and specious groups of Lycidae in the Neotropical region, such as Calopteron Guérin-Méneville, 1830 (Lycinae, Calopterini) and Plateros Bourgeois, 1879 (Lycinae, Platerodini), to mention two very emblematic cases, are almost impossible to be identified at species level. The majority of recent taxonomic works in Neotropical Lycidae focus in relatively small and less diverse genera of Lycidae (e.g., Nascimento & Bocakova, 2009; Ferreira & Ivie, 2016). Most of the challenges associated with the identification of previously described taxa in Lycidae are intimately related to the fact that most descriptions came from early entomologists from the 19th and 18th century, such as Maurice Pic (1866‑1957), Henry S. Gorham (1839‑1920), George R. Waterhouse (1815‑1898) and others, authors known to be very succinct and, in many cases, even misleading in their descriptions and works – Pic’s publications in particular (see Bocakova, 2001, p. 53). In addition, the taxonomic impediment plays a big role in this matter, as most type specimens and a significant portion of literature are currently inaccessible, lost or of difficult access in European collections, turning the identification of Lycidae a Herculean task. During the course of LFS’s doctoral research, VSF was approached to help with the identification of Lycidae present in his by-catch Malaise trap samples from the Serra dos Órgãos mountain Pap. Avulsos Zool., 2020; v.60.special-issue: e202060(s.i.).35 http://doi.org/10.11606/1807-0205/2020.60.special-issue.35 http://www.revistas.usp.br/paz http://www.scielo.br/paz Edited by: Sônia A. Casari / Gabriel Biffi Received: 26/12/2019 Accepted: 07/02/2020 Published: 04/03/2020 ISSN On-Line: 1807-0205 ISSN Printed: 0031-1049 ISNI: 0000-0004-0384-1825 http://zoobank.org/DFC62BE1-B7B6-47B9-AF4E-B694BE90AD50 Pap. Avulsos Zool., 2020; v.60.special-issue: e202060(s.i.).35 2/6 Ferreira, V.S. & Silveira, L.F.L.: A new Lycidae genus from Brazil MATERIAL AND METHODS Photos were taken using a JVC (DC Ky‑F75U) digital camera on a Leica® MS5 stereoscope and a Canon T3i DSLR with lenses MP‑E 65 mm using a Stackshot™ – automated macro rail for focus stacking. Images were stacked using the software Zerene Stacker® software version 1.04. Enhancements to digital images were made in Adobe Photoshop® CC 2019. Drawings were prepared based on photographs using the Adobe Illustrator® CC 2019. Morphological terminology follows Bocak & Bocakova (1990), Kazantsev (2003) and Lawrence et al. (2011). Transcription of label data from specimens follows Ivie (1985): the end of each line on a label is indicated by a “;” (semicolon); the individual labels are separated by a “/” (slash). Specimens were collected in the Parque Nacional da Serra dos Órgãos (PARNASO), located at the Serra do Mar mountain range, in the Atlantic Rainforest of Southeastern Brazil (Roza et al., 2017). The examined material is permanently deposited in the following collections (respective curators are indicated in parentheses): MNRJ: Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (Marcela Monné); MTEC: Montana Entomology Collection, Montana State University, Bozeman, USA (Michael A. Ivie); MZSP: Museu de Zoologia, Universidade de São Paulo, São Paulo, Brazil (Sônia Casari). Specimens were studied under a Leica® Wild M3C stereoscopic microscope with magnification up to 40×. RESULTS range in Rio de Janeiro state, Brazil. The initial examination to that material caught VSF’s attention, as among that material a single specimen, unique and completely unknown to him was spotted. An initial assessment indicated that the mysterious beetle was, indeed, an undescribed genus and species. However, because only one specimen of that beetle was available at the time, the author’s decided to not go ahead with the description of the new taxon and wait until more material could be found. In the last couple of years, with the re-examination of LFS’s samples by the authors and other colleagues, more specimens of the mysterious beetles were found, which motivated us to carry on with this description. Herein we take this opportunity to report a new monospecific Lycidae genus from the Atlantic Rainforest in Rio de Janeiro, Brazil, tentatively placed in the tribe Calopterini (...truncated)