DOI: 10.5061/dryad.w3r2280s7
title: Haplocauda, a new genus of fireflies endemic to the Amazon Rainforest (Coleoptera: Lampyridae)

description: Most firefly genera have poorly defined taxonomic boundaries, especially
 in the Neotropics, where they are more diverse and more difficult to
 identify. Recent advances that shed light on the diversity of fireflies in
 South America have focused mainly on Atlantic Rainforest taxa, whereas
 lampyrids in other biomes remained largely unstudied. We found three new
 firefly species endemic to the Amazon basin that share unique traits of
 the male abdomen where sternum VIII and the pygidium are modified and
 likely work as a copulation clamp. Here we test and confirm the hypothesis
 that these three species form a monophyletic lineage and propose
 Haplocauda gen. nov. to accommodate the three new species. Both Maximum
 Parsimony and probabilistic (Bayesian and Maximum Likelihood) phylogenetic
 analyses confirmed Haplocauda gen. nov. monophyly, and consistently
 recovered it as the sister group to Scissicauda, fireflies endemic to the
 Atlantic Rainforest that also feature a copulation clamp on abdominal
 segment VIII, although with a different configuration. We provide
 illustrations, diagnostic descriptions, and keys to species based on males
 and females. The three new species were sampled from different regions,
 and are likely allopatric, a common pattern among Amazonian taxa.
description: <strong>Morphology, terminology, and
 map</strong> Specimens of these distinctive new
 species were located at two institutions: the Brazilian National Institute
 of Amazonian Research (INPA) and University of Georgia Collection of
 Arthropods (UGCA). The abdomen was removed from 2 male and 1–2 female
 specimens per species and soaked in 10% KOH for 24–36h. This clearing
 procedure was also applied to two entire specimens representing one of the
 three new species. The morphology was examined under a Leica M205 C
 stereomicroscope, and photographs were made with the Leica Application
 Suite X Auto-montage Software. We follow the classification of Martin et
 al. (2019), and the anatomical terminology of Silveira et al. (2016a).
 Distribution maps of the species were made using QGIS 3.10.14 (QGIS 2021).
 We recorded label data for all type specimens using the following
 conventions: double quotes (“ ”) for label data quoted verbatim; double
 forward slashes (// ) separate labels; double comma (,,) for line breaks;
 brackets [ ] enclose our comments or notes. All labels are typed, unless
 otherwise noted. <strong>Phylogenetic
 analyses</strong> We ran phylogenetic analyses
 with two goals: (i) test the hypothesis that the three new species bearing
 the distinctive abdominal morphology constituted a monophyletic group;
 and, if so, (ii) explore the placement of that group within Lampyridae. Of
 particular interest were the phylogenetic relationships of the new species
 with Lampyrinae Rafinesque, 1815, a subfamily that includes several taxa
 sharing similar anatomical features with the new species (see
 below). Lampyrid classification remains unstable
 despite recent advances (e.g., Martin et al., 2019) and relationships
 among genera, as well as their monophyly, remain largely unexplored
 outside Luciolinae (Ballantyne et al., 2019; but see Vaz et al., 2020; Vaz
 et al., 2021; and Silveira et al., 2021). In order to determine the
 placement of these new species in Lampyridae, we included in our taxon
 sampling representatives of the four subfamilies that are known to occur
 in South America, namely: Psilocladinae (Psilocladus miltoderus Blanchard,
 1846), Amydetinae (Amydetes fastigiata Illiger, 1807), Cladodinae
 (Cladodes flabellatus Solier, 1849; Bocakova et al., in press), and
 Lampyrinae, in addition to taxa incertae sedis (Araucariocladus hiems
 Silveira & Mermudes, 2017, and Vesta thoracica Olivier, 1790). We
 included a denser sampling of Lampyrinae because the new species shared
 many similarities with the lampyrine Costalampys Silveira, Roza, Vaz
 & Mermudes, 2021 and Scissicauda McDermott, 1964, which was
 transferred to Lampyrinae in Martin et al. (2019). A summary of the
 classification adopted here is given in Table 1. Data for the material
 examined of the new species is given below (see Results), and additional
 material used in the phylogenetic analyses is provided in Supp. Mat.
 1.  Using MESQUITE (Maddison & Maddison, 2017),
 we built a matrix with 20 taxa scored for 76 characters following the
 guidelines of Sereno (2007). The data include 55 characters reanalyzed
 from Silveira et al. (2021) combined with 21 new characters (see Results;
 Supp. Mat. 2). Measurement-based characters are taken at the longest or
 the widest point ​​of the respective structure. Key character states are
 labeled in figures, abbreviated as C:S, where C and S indicates character
 and state number, respectively, followed by the numbers of
 interest. In order to compare the outcomes of multiple
 phylogenetic approaches, we performed Maximum Parsimony (MP) analyses in
 TNT (Goloboff et al., 2016), Bayesian inference (BI) in MrBayes 3.2.7a
 (Huelsenbeck et al., 2001; Ronquist et al., 2012) (available at The CIPRES
 Science Gateway V. 3.3 [phylo.org] – Miller et al., 2010), and Maximum
 Likelihood inference in IQTREE 1.6.12 (Minh et al., 2020).
 We ran the MP analyses using New Technology heuristic searches
 with Tree Bisection and Reconnection, with equal and implied weights (EW
 and IW, respectively), scaling the k parameter from 0.5–50 to investigate
 how homoplasy impacts tree topology (Goloboff, 2008; Mirande, 2009). Node
 support was assessed using the Bremer Index and standard bootstrapping
 (for MP–EW), and symmetric resampling (for MP–IW) with 1000 replicates.
 Character evolution was optimized using WINCLADA (Nixon, 2002). 
 The BI analysis implemented the MKV model, modified from MK to
 account for ascertainment bias due to the prior exclusion of invariant
 characters in our matrix (Lewis, 2001), in addition to among-character
 rate variation with 8 rate categories for tractability (Wright, 2019). We
 ran 50,000,000 generations, saving trees each 2000 generations, and
 discarding the first 25% as burn-in. We checked for convergence using
 Tracer v1.6 (Rambaut et al., 2014). We compared the fit and the topologies
 of the BIMKV with gamma and lognormal rate distribution, since each was
 found to provide dataset-specific improvements to evolutionary models by
 Harrison & Larsson (2015). For the ML, we obtained estimates of
 branch support with Ultrafast bootstrapping with 1000 replicates, in
 IQTREE. To compare the three main topologies obtained (i.e. MLG [shared
 with MPEQ], BIG, and BILN), we performed pairwise comparisons in IQTREE,
 and applied the SH (Shimodaira and Hasegawa, 1999) and AU (Shimodaira,
 2002) statistical tests. Trees were read in FigTree
 version 1.4.4 (obtained at https://github.com/rambaut/figtree/releases),
 and the different measures of node support obtained (Bremer index,
 Bootstrap, Ultrafast Bootstrap, and posterior probabilities) were placed
 on the preferred topology (see below) using Adobe Photoshop
 2021. 
description: Captions: Haplocauda_BI_Mk_Gamma.con.tre –
 Consensus Bayesian tree file with node probabilities, MKV model with
 ascertainment bias, with gamma distribution (eight categories).
 Haplocauda_BI_Mk_lnorm_ncat8.con.tre – Consensus Bayesian tree
 file with node probabilities, MKV model with ascertainment bias, with
 lognormal distribution (eight categories).
 Haplocauda_BI_Mk.con.tre – Consensus Bayesian tree file with node
 probabilities, MKV model with ascertainment bias, with fixed
 rates. Haplocauda_ML_MK_G.treefile – Maximum Likelihood
 tree file with three measurements of node support (aLRT, Bayesian aLRT,
 UFBOOT2), MKV model with ascertainment bias, with gamma distribution
 (eight categories). Haplocauda_ML_MK.treefile – Maximum
 Likelihood tree file with three measurements of node support (aLRT,
 Bayesian aLRT, UFBOOT2), MKV model with ascertainment bias, with fixed
 rates. Haplocauda_Parsimony_equal_weight.nex –
 Parsimony consensus tree after equal weights, with Bremer support and
 bootstrap values.
 Haplocauda_Parsimony_implied_weights_1.nex – Parsimony consensus
 tree after implied weighing (k=1), with symmetric resampling
 values. Haplocauda_Supp_Mat_2_SimpNEX_Dec_2021.nex –
 Morphological data matrix as simplified nexus