The pelidnotine scarabs (Scarabaeidae: Rutelinae: Rutelini) are a speciose, paraphyletic assemblage of beetles that includes spectacular metallic species (“jewel scarabs”) as well as species that are ecologically important as herbivores, pollinators, and bioindicators. These beetles suffer from a complicated nomenclatural history, due primarily to 20^th century taxonomic and nomenclatural errors. We review the taxonomic history of the pelidnotine scarabs, present a provisional key to genera with overviews of all genera, and synthesize a catalog of all taxa with synonyms, distributional data, type specimen information, and 107 images of exemplar species. As a result of our research, the pelidnotine leaf chafers (a paraphyletic group) include 27 (26 extant and 1 extinct) genera and 420 valid species and subspecies (419 extant and 1 extinct). Our research makes biodiversity research on this group tractable and accessible, thus setting the stage for future studies that address evolutionary and ecological trends. Based on our research, 1 new species is described, 1 new generic synonym and 12 new species synonyms are proposed, 11 new lectotypes and 1 new neotype are designated, many new or revised nomenclatural combinations, and many unavailable names are presented. The following taxonomic changes are made:

New generic synonym: The genus Heteropelidnota Ohaus, 1912 is a new junior synonym of Pelidnota MacLeay, 1819.

New species synonyms: Plusiotis adelaida pavonacea Casey, 1915 is a syn. n. of Chrysina adelaida (Hope, 1841); Odontognathus gounellei Ohaus, 1908 is a revised synonym of Pelidnota ebenina (Blanchard, 1842); Pelidnota francoisgenieri Moore & Jameson, 2013 is a syn. n. of Pelidnota punctata (Linnaeus, 1758); Pelidnota genieri Soula, 2009 is a syn. n. of Pelidnota punctata (Linnaeus, 1758); Pelidnota lutea (Olivier, 1758) is a revised synonym of Pelidnota punctata (Linnaeus, 1758); Pelidnota (Pelidnota) texensis Casey, 1915 is a revised synonym of Pelidnota punctata (Linnaeus, 1758); Pelidnota (Strigidia) zikani (Ohaus, 1922) is a revised synonym of Pelidnota tibialis tibialis Burmeister, 1844; Pelidnota ludovici Ohaus, 1905 is a syn. n. of Pelidnota burmeisteri tricolor Nonfried, 1894; Rutela fulvipennis Germar, 1824 is syn. n. of Pelidnota cuprea (Germar, 1824); Pelidnota pulchella blanda Burmeister, 1844 is a syn. n. of Pelidnota pulchella pulchella (Kirby, 1819); Pelidnota pulchella scapularis Burmeister, 1844 is a syn. n. of Pelidnota pulchella pulchella (Kirby, 1819); Pelidnota xanthogramma Perty, 1830 is a syn. n. of Pelidnota pulchella pulchella (Kirby, 1819).

New or revised statuses: Pelidnota fabricelavalettei Soula, 2009, revised status, is considered a species; Pelidnota rioensis Soula, 2009, stat. n., is considered a species; Pelidnota semiaurata semiaurata Burmeister, 1844, stat. rev., is considered a subspecies.

New or comb. rev. and revised status: Plusiotis guaymi Curoe, 2001 is formally transferred to the genus Chrysina (C. guaymi (Curoe, 2001), comb. n.); Plusiotis transvolcanica Morón & Nogueira, 2016 is transferred to the genus Chrysina (C. transvolcanica (Morón & Nogueira, 2016), comb. n.). Heteropelidnota kuhnti Ohaus, 1912 is transferred to the genus Pelidnota (P. kuhnti (Ohaus, 1912), comb. n.); Odontognathus riedeli Ohaus, 1905 is considered a subspecies of Pelidnota rubripennis Burmeister, 1844 (Pelidnota rubripennis riedeli (Ohaus, 1905), revised status and comb. rev.); Pelidnota (Strigidia) acutipennis (F. Bates, 1904) is transferred to the genus Sorocha (Sorocha acutipennis (F. Bates, 1904), comb. rev.); Pelidnota (Odontognathus) nadiae Martínez, 1978 is transferred to the genus Sorocha (Sorocha nadiae (Martínez, 1978), comb. rev.); Pelidnota (Ganonota) plicipennis Ohaus, 1934 is transferred to the genus Sorocha (Sorocha plicipennis (Ohaus, 1934), comb. rev.); Pelidnota similis Ohaus, 1908 is transferred to the genus Sorocha (Sorocha similis (Ohaus, 1908), comb. rev.); Pelidnota (Ganonota) yungana Ohaus, 1934 is transferred to Sorocha (Sorocha yungana (Ohaus, 1934), comb. rev.); Pelidnota malyi Soula, 2010: 58, revised status; Xenopelidnota anomala porioni Chalumeau, 1985, revised subspecies status.

To stabilize the classification of the group, a neotype is designated for the following species: Pelidnota thiliezi Soula, 2009. Lectotypes are designated for the following names (given in their original combinations): Pelidnota brevicollis Casey, 1915, Pelidnota brevis Casey, 1915, Pelidnota debiliceps Casey, 1915, Pelidnota hudsonica Casey, 1915, Pelidnota oblonga Casey, 1915, Pelidnota pallidipes Casey, 1915, Pelidnota ponderella Casey, 1915, Pelidnota strenua Casey, 1915, Pelidnota tarsalis Casey, 1915, Pelidnota texensis Casey, 1915, and Scarabaeus punctatus Linnaeus, 1758.

The following published infrasubspecific names are unavailable per ICZN Article 45.6.1: Pelidnota (Odontognathus) cuprea var. coerulea Ohaus, 1913; Pelidnota (Odontognathus) cuprea var. rufoviolacea Ohaus, 1913; Pelidnota (Odontognathus) cuprea var. nigrocoerulea Ohaus, 1913; Pelidnota pulchella var. fulvopunctata Ohaus, 1913; Pelidnota pulchella var. sellata Ohaus, 1913; Pelidnota pulchella var. reducta Ohaus, 1913; Pelidnota unicolor var. infuscata Ohaus, 1913.

The following published species name is unavailable per ICZN Article 11.5: Neopatatra synonyma Moore & Jameson, 2013.

The following published species name is unavailable per application of ICZN Article 16.1: Parhoplognathus rubripennis Soula, 2008.

The following published species name is unavailable per application of ICZN Article 16.4.1: Strigidia testaceovirens argentinica Soula, 2006, Pelidnota (Strigidia) testaceovirens argentinica (Soula, 2006), and Pelidnota testaceovirens argentinica (Soula, 2006).

The following published species names are unavailable per application of ICZN Article 16.4.2: Homonyx digennaroi Soula, 2010; Homonyx lecourti Soula, 2010; Homonyx mulliei Soula, 2010; Homonyx simoensi Soula, 2010; Homonyx wagneri Soula, 2010; Homonyx zovii Demez & Soula, 2011; Pelidnota arnaudi Soula, 2009; Pelidnota brusteli Soula, 2010; Pelidnota chalcothorax septentrionalis Soula, 2009; Pelidnota degallieri Soula, 2010; Pelidnota lavalettei Soula, 2008; Pelidnota lavalettei Soula, 2009; Pelidnota dieteri Soula, 2011; Strigidia gracilis decaensi Soula, 2008, Pelidnota (Strigidia) gracilis decaensi (Soula, 2008), and Pelidnota gracilis decaensi (Soula, 2008); Pelidnota halleri Demez & Soula, 2011; Pelidnota injantepalominoi Demez & Soula, 2011; Pelidnota kucerai Soula, 2009; Pelidnota malyi Soula, 2010: 36-37; Pelidnota mezai Soula, 2009; Pelidnota polita darienensis Soula, 2009; Pelidnota polita orozcoi Soula, 2009; Pelidnota polita pittieri Soula, 2009; Pelidnota punctulata decolombia Soula, 2009; Pelidnota punctulata venezolana Soula, 2009; Pelidnota raingeardi Soula, 2009; Pelidnota schneideri Soula, 2010; Pelidnota simoensi Soula, 2009; Pelidnota unicolor subandina Soula, 2009; Sorocha carloti Demez & Soula, 2011; Sorocha castroi Soula, 2008; Sorocha fravali Soula, 2011; Sorocha jeanmaurettei Demez & Soula, 2011; Sorocha yelamosi Soula, 2011; Xenopelidnota bolivari Soula, 2009; Xenopelidnota pittieri pittieri Soula, 2009.

Due to unavailability of the name Pseudogeniates cordobaensis Soula 2009, we describe the species as intentionally new (Pseudogeniates cordobaensis Moore, Jameson, Garner, Audibert, Smith, and Seidel, sp. n.).

leaf chafers, jewel beetles, New World, taxonomy

The pelidnotine leaf chafers (Rutelinae: Rutelini) include the brilliantly metallic jewel scarabs (Chrysina spp.; e.g., Fig. 10), large, showy species that are used in ornamentation and jewelry (e.g., Chrysophora chrysochlora [Latreille]; Fig. 13), and species that exhibit dramatic sexual dimorphism (e.g., the bulging and dilated hind legs of male Pelidnota burmeisteri burmeisteri Burmeister; Fig. 56). The intensely lustrous, metallic colors of Chrysina Kirby species have been studied for their rare, cuticular reflection of circularly polarized light (Sharma et al. 2009, Pye 2010). Further studies have demonstrated that this may reduce predation by allowing for communication between conspecifics while remaining cryptic to avoid detection by predators (Brady and Cummings 2010). Ecologically, the leaf chafers have been proposed as valuable bioindicators of high-quality forest (Morón et al. 1997). The group is named for their leaf herbivory tendencies as adults, yet some species may also serve as pollinators of flowering plants (e.g., Pelidnota sumptuosa Vigors visits the flowers of Rourea induta Planch. and Stryphnodendron adstringens (Mart.) Coville in Brazil) (Gottsberger and Silberbauer-Gottsberger 2006). The extant pelidnotine leaf chafers are entirely distributed in the New World and include endemic genera such Pseudogeniates Ohaus (endemic to Argentina) and Homothermon Ohaus (endemic to Paulista center of endemism in Brazil), as well as widespread genera such as Pelidnota MacLeay (distributed from Canada to central Argentina).

Pelidnotine leaf chafers are a poorly studied group with a great need for systematics research. The lack of a taxonomic and phylogenetic framework remains an impediment to the circumscription of natural, monophyletic groups within the Rutelini. Lacking this essential foundation, we cannot understand the evolution of characters such as circular polarization of light in the cuticle of these beetles, the broad context of ecological services such as pollination that the species may provide, and we cannot reconstruct biogeographic patterns nor predict future distributional changes of genera and species of Rutelini.

The objective of this paper is to provide a foundation for understanding the taxonomy of 27 (26 extant and 1 extinct) genera and over 400 species of pelidnotine beetles, assist in stabilizing the classification and nomenclature of the genera, enable identification of genera, and provide a foundation for continued biodiversity research on leaf chafer scarabs. This work synthesizes the taxonomic and biodiversity literature for the pelidnotine scarabs, also encapsulating work that assisted in clarifying the nomenclature for the group (Moore and Jameson 2013, Moore et al. 2014). For the purposes of this research, we refer to this paraphyletic assemblage of taxa as the “pelidnotine scarabs,” and it is our aim that this work will set the stage for future research that addresses broad trends and patterns within the ruteline scarabs.

Legacy and history. Fredrick Bates (1829–1903, collection at BMNH), the younger brother of the well-known tropical biologist and coleopterist Henry Walter Bates (see O’Hara 1995), also had a love for taxonomy and entomology. He conducted research on the Heteromera (Tenebrionoidea) and the pelidnotine scarab beetles. Fredrick Bates died in 1903, and his single work on scarabs was published posthumously with the aid of Gilbert Arrow (The Natural History Museum). In the introduction, Arrow stated: “this revision of a difficult group of beetles represents many months of constant and strenuous investigation, continued to within a very few days of my friend’s death” (Arrow in Bates 1904: 249). Bates had intended the work to be more comprehensive, but his health did not allow further research. Upon Bates’s request, Arrow finished the work. Arrow stated that he confined himself to editorial functions with the exceptions of a few additions and modifications. Some of these modifications are clear within the text as evidenced by brackets and Arrow’s initials. For example, the commentary and diagnosis for the genus Mecopelidnota F. Bates and M. arrowi F. Bates were clearly added by Arrow.

Friedrich Ohaus (1864–1946, collection at ZMHB) was a student of coleopterist Edgar von Harold and a practicing medical doctor, which allowed him to travel to South America as a ship’s doctor. Ohaus provided the most comprehensive body of literature on world Rutelinae, and he developed the classification of the subfamily Rutelinae that is still used today. His work synthesized the body of knowledge on this highly biodiverse group, providing catalogs of species and their distributions, keys to higher-level groups, natural history, illustrations, and interpretation of characters. Ohaus’s classification of subtribes and genera is largely artificial, but this was a reflection of the state of systematics at the time. The Genera Insectorum on the Rutelini (Ohaus 1934b) was delayed for more than 20 years before publication. Instead of waiting for this larger, comprehensive catalog to be completed, Ohaus (1915b) published his concepts on some subtribal taxa within Rutelini and included descriptions of genera. In this work, he formalized the use of the subtribe Pelidnotina (as “Pelidnotinorum”) (Ohaus 1915b).

Johann W. Machatschke (1912–1975, collection at NHMB) continued Ohaus’s work, completing the Genera Insectorum volumes on Orthochilous Rutelinae (Anoplognathini, Adoretini, Anatistini) as well as Anomalini. He was the curator of the Coleoptera at Deutsche Entomologische Institut (DEI) in Berlin and later at the Museum G. Frey in Tutzing near Munich.

Marc Soula (1947–2012, collection at CCECL) was a mathematics teacher and naturalist who lived in Massat, France. He traveled broadly to South America and Thailand where he collected Rutelinae. At the Muséum National d’Histoire Naturelle in Paris, he began his life-long work on Rutelinae. Soula, in the fashion of Sciences Nat volumes, created guides to assorted rutelines, particularly the larger and showier groups. These volumes, which were published in parts, provide a preliminary effort to understand the diversity in the group. The benefit of these guides is that they provide color images of most species (dorsal habitus and often male genitalia) and species names that, in most cases, were verified by type examination. However, unlike monographic revisions, these guides suffer many shortfalls. They are based on a very limited number of specimens (often holotype specimens only), lack generalized distributional data and, prior to his death in 2012, most holotypes of species named by Soula were unavailable for general study because they were deposited in his personal collection. Soula’s works were written in an unusual style for scientific work. In effect, they were a “stream of consciousness” and lacked synthesis, analysis, and did not make meaningful interpretations or comparisons of characters. Rather than synthesizing his body of work, he published his work in disjunct parts. Sprinkled throughout the volumes (sometimes in red font, sometimes in bold font) he provided corrections to previous volumes such as amended taxonomic decisions, new combinations, new synonymies, and new distributions. These notes are very difficult to track and contributed to Soula’s numerous errors (synonyms, homonyms, lapsus calami, unavailable names, and transcriptional errors) (Moore and Jameson 2013, Moore et al. 2014). Soula’s guides provided an outlet for description of many new genera, species, and subspecies, but lacked unified species- or generic-level concepts. Additionally, Soula’s ruteline volumes were not peer-reviewed, were not widely available, and were expensive (thus reducing access). Because the volumes were not peer-reviewed, the data in them were not subjected to the objective scrutiny of other experts on phytophagous scarabs or agreed upon through scientific consensus. The volumes were not well edited, and they suffer from many misspellings (e.g., localities and scientific names), language that is not concise, and omissions (e.g., in the index and catalog). In addition, the lack of peer review and proper scientific editing for Soula’s volumes left numerous published names unavailable when the zoological rules of nomenclature (ICZN 1999) are applied due to various shortcomings and rule violations in the descriptions. Soula’s large collection of Rutelinae now resides in the Musée des Confluences, Lyon, France where it is databased, curated, and accessible for biodiversity research.

Higher-level nomenclature. Many of Soula’s descriptions of new genera within the Rutelini lack information regarding higher-level classification (e.g., Patatra Soula, Pachacama Soula, and Homeochlorota Soula were not clearly assigned to a subtribe of Rutelini at the time of their description). Because his work was published in parts, they included a mix of many genera from formerly accepted subtribes (Pelidnotina, Anticheirina) or accepted subtribes (Areodina, Lasiocalina), and they were not organized in a systematic manner. Thus, Soula’s tribal and subtribal classification within the Rutelinae was not clear. Soula recognized that his classification was not based on monophyletic groups (“La plupart des taxons supragénériques, n’étant pas monophylétiques...” [Soula 2011: 3]), but he maintained this classification pending further phylogenetic research. At the same time, however, he abandoned the subtribe Lasiocalina (Soula 2006) based on “dissimilarity” of the two genera included by Ohaus (1934b), but he failed to reclassify taxa in the group. Later, Soula (2011) revalidated the subtribe Lasiocalina without discussion. Soula’s classification (Soula 2011) omitted Rutelinae tribes (Alvarengiini and Adoretini) and included subtribes that are no longer accepted (e.g., Anticheirina, Pelidnotina) (Smith 2006, Bouchard et al. 2011). Additionally, Soula’s (2011) classification contradicted information in previous publications including the classification of Minilasiocala Soula (=Microogenius Gutiérrez) in the lasiocaline scarabs versus the pelidnotine scarabs (Soula 2006) and the classification of Pseudochlorota Ohaus and Lasiocala Blanchard as both pelidnotines and lasiocalines (Soula 2011). Two genera that were formerly included in the subtribe Pelidnotina were omitted by Soula (2011): Oogenius Solier and Eremophygus Ohaus. Because Soula provided no characters or justification for his higher classification and existing phylogenetic evidence demonstrates that Pelidnotina and Anticheirina are not monophyletic groups (Jameson 1998), we follow the classification of Bouchard et al. (2011) which lists these subtribes in synonymy under Rutelini.

Nomenclature. Pelidnota was placed on the Official List of Generic Names in Zoology (ICZN 2003) and included in the subtribe Rutelina (tribe Rutelini) by Bouchard et al. (2011). Although the subtribe Rutelina was hypothesized to be paraphyletic (Jameson 1998), it is the name-bearer for higher-level taxa (Rutelinae, Rutelini). The name has nomenclatural priority over the names Chasmodiidae Burmeister, Chrysophoridae Burmeister, Macraspididae Burmeister, Pelidnotidae Burmeister, Antichirides Lacordaire, Plusiotina Bates, and Fruhstorferina Ohaus (Bouchard et al. 2011).

The type species of Pelidnota is Scarabaeus punctatus Linnaeus, 1758. To ensure nomenclatural stability, the name was conserved due to homonymy with Scarabaeus punctatus Villers, 1789 (the dynastine scarab Pentodon bidens punctatus [Villers]) (ICZN 1999, Krell et al. 2012, Moore and Jameson 2013).

The name “Pelidnota” (from which the subtribe Pelidnotina takes its name) is derived from the blackish markings (“pelidnos” or “pelios” = Greek for black; “nota”=Latin for markings) that are common on the elytra of North American Pelidnota species.

Life history and biology. Immature life stages are known for only a handful of the pelidnotine genera including Homonyx Guérin-Méneville (Morelli 1996), Chrysina (Ritcher 1966, Morón 1976, 1985, Morón and Deloya 1991), Chrysophora Dejean (Pardo-Locarno and Morón 2007), and Pelidnota (Ritcher 1945, 1966, Morón 1976, Morón and Deloya 2002, Rodriguez et al. 2012, Garcia et al. 2013). Based on life history studies, life cycles are one to two years in duration (Ritcher 1966, Morón 1976, Morelli 1996). Larvae are sapro-xylophagous (Morón 1991) and feed on dry, rotten wood (Pelidnota virescens Burmeister; Morón and Deloya 2002), hollow trunks and tree stumps (P. punctata (Linnaeus) [Hoffman 1926]; Epichalcoplethis velutipes Arrow [Chalumeau 1985]), organic matter in the soil, and rotten roots (Morón 1991). One species, P. filippiniae Soula, is a significant defoliator and high numbers could contribute to plantation damage (Lunz et al. 2011).

Human cultural uses. The beauty, large size, and ease of collecting of many pelidnotine leaf chafers have promoted the cultural use of many species. For example, in Ecuador and Peru, the Jivaro and Sequoia Indians use the brilliant, metallic green elytra, pronota, or entire bodies of Chrysophora chrysochlora (Latreille) to make necklaces and headdresses (Ratcliffe 2006, Ratcliffe et al. 2015). In Guatemala, local people developed a cottage industry for tourists creating pendants, bracelets, and bola ties using local species of Chrysina (Woodruff 2009). The Yanomami people of Venezuela and Brazil extract and eat the larvae of Pelidnota sp. (known as “Makoia”) from logs in their gardens (Paoletti et al. 2000, Paoletti and Dufour 2005). Many attractive pelidnotine chafers are used in natural, artistic displays, including those of designer and photographer Christopher Marley (Marley 2008).

Fossil pelidnotines. Fossil organisms provide important information on ancestral character states, habitats, ecosystems, and adaptations. The only known leaf chafer fossil sets the minimum age of the subfamily Rutelinae at 50-42 mya (Krell 2006). The pelidnotine-like Pelidnotites atavus Cockerell is from the Eocene of England in the Bartonian Bagshot Beds of Bournemouth (Cockerell 1920, Carpenter 1992). Cockerell (1920) described the fossil belonging to the Rutelini and “in the vicinity of Pelidnota and Cotalpa” (Cockerell 1920: 463). This fossil should be examined to place the taxon within the Rutelini and to hypothesize sister-group relationships. No pelidnotine relatives are currently distributed in England or the Old World. Thus, this fossil revealed distributional patterns quite different from the current range of the pelidnotine Rutelini.

Identification of pelidnotine scarabs. Keys to the genera of “Pelidnotina” were created by F. Bates (1904) and Ohaus (1934b), and these provided a weak foundation for future work in the group. Bates’s (1904) posthumous work was based almost exclusively upon specimens available to him at the Natural History Museum (BMNH). Because this collection did not contain all described taxa in Pelidnotina, the revision and key were incomplete. Keys to genera and species groups that were provided by Ohaus (1934b) are not adequate for reliable identification of pelidnotine scarabs. Many of Ohaus’s (1934b) couplets are, in our estimation unclear, asymmetrical, and based on characters that vary widely across species and genera of Pelidnotina. Soula’s (2006) key to pelidnotine genera was based on Ohaus’s keys. Soula’s (2006) key omitted five genera that were newly described or elevated to generic status by Soula (Chipita Soula, Epichalcoplethis Burmeister, Pachacama, Patatra, and Sorocha Soula) and included genera that previously had been transferred out of Rutelini or synonymized (Pelidnotopsis Ohaus, Peltonotus Burmeister, and Plusiotis Burmeister) (see Moore and Jameson 2013). To date, there is no reliable, comprehensive key that facilitates accurate and repeatable identification of pelidnotine genera by non-experts. We think that consistent generic- and species-level identification of pelidnotine scarabs is not possible at this time. This lack of basic information is a great impediment to biodiversity and ecological research on pelidnotines

Classification and phylogeny. The leaf chafers (Rutelini) are members of the phytophagous scarab beetle clade (Melolonthinae, Cetoniinae, Dynastinae, Rutelinae, and a few minor subfamilies), a group that has been widely accepted as monophyletic for about 150 years and corroborated by molecular and morphological phylogenetic studies (Smith et al. 2006, Ahrens et al. 2011, McKenna et al. 2014). At the tribal- and subtribal-level morphological phylogenetic analyses demonstrated the inadequacies of the Rutelini classification sensu Machatschke (1972) (Jameson 1998). Based on this research, several subtribes (e.g., Pelidnotina, Anticheirina, and Rutelina) in the Rutelini were not monophyletic and, in fact, they were uninformative and logically inconsistent (Jameson 1998). Paraphyly of the ruteline subtribes has been a matter of discussion for well over a century. In his work on the pelidnotine scarabs, F. Bates (1904) noted the “close relationship” of Pelidnota and Rutela Latreille, and this idea was corroborated based on phylogenetic analyses of Rutelinae (Jameson 1998, Ahrens et al. 2011). Jameson (1998) provided the basis for elimination of the subtribe Pelidnotina and concluded that many genera were poorly characterized and not based on synapomorphic or autapomorphic characters.

Relationships among the pelidnotine scarabs need to be addressed by phylogenetic analyses. Pelidnotine genera, especially Pelidnota and the generic-level synonyms of Pelidnota (e.g., Strigidia Burmeister), should be re-structured into monophyletic groups with clear hypothesized synapomorphies. Based on phylogenetic analyses (Jameson 1998), Pelidnota and several related genera form a grade of taxa that are currently treated as genera or subgenera. Because of the poor understanding of the group and the lack of synapomorphies delimiting genera, past workers elevated distinctive species to the rank of genus, thus creating many monotypic genera (e.g., Pelidnotopsis [=Chrysina] and Ectinoplectron Ohaus). Hardy (1975) did not discuss relationships among the subgenera of Pelidnota, although he noted that the classification and subgeneric concept as proposed by Ohaus were in need of study. In our estimation, several of the current pelidnotine genera are probably not valid and Pelidnota, in particular, is likely to include several distinct, monophyletic groups (i.e., at the generic-level).

Research on specific pelidnotine genera has led to classification changes that affected the composition of pelidnotine scarabs. For example, Plusiotis and Chrysina were historically separate genera. As new species were described, our understanding of characters that circumscribe these groups was broadened and, as stated by Morón and Howden (1992: 208), the “characters that have been used to separate Plusiotis and Chrysina form a non-concordant mosaic.” Based on molecular and morphological data, Hawks (2001) synonymized Plusiotis as well as Pelidnotopsis within the genus Chrysina. Additionally, revisionary research on the genus Peltonotus, which was considered a member of the pelidnotine scarabs, provided sound evidence that the genus Peltonotus is closely related to members of the subfamily Dynastinae rather than the Rutelinae (Jameson and Wada 2004, 2009, Smith et al. 2006, Jameson and Drumont 2013). In spite of phylogenetic evidence that the subtribe Pelidnotina was paraphyletic, Soula (2006, 2008, 2009) maintained the subtribe, maintained the generic composition of the subtribe by including genera that had been transferred or synonymized, and he refrained from re-characterizing the group in any way.

We reiterate that Pelidnotina, as historically defined, is a paraphyletic grouping of disparate genera and species, and it should not be considered a valid taxon. We consider the subtribe a synonym of the subtribe Rutelina (Jameson 1998, Bouchard et al. 2011). We refer to “pelidnotine scarabs” in order to: 1) synthesize information on a group of genera that was chaotically treated by Soula, 2) incorporate genera new to the subfamily Rutelinae and previously of uncertain tribal placement (Peruquime Mondaca and Valencia and Neogutierrezia Martínez), 3) provide a mechanism for generic identification (in the form of a provisional dichotomous key), and 4) set the stage for future research that addresses broader trends within the Rutelini scarabs.

Specimens and taxonomic material. Specimens examined for this study were provided by many institutions and private collections. We include information on type specimens to provide a foundation for continued research in the leaf chafers. Type specimens are international standards for scientific names (Knapp et al. 2004) and are tied to species hypotheses. The type specimen provides the nomenclatural stability that assures that the name reflects the described species and is linked through history in the literature. Acronyms for loaning institutions follow Evenhuis (2016).

BIOG Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada (Renee Labbee)

BMNH The Natural History Museum, London, United Kingdom (Max Barclay, Beulah Garner)

CAS California Academy of Sciences, San Francisco, California, USA (Norman Penny)

CCECL Musée des Confluences, Lyon, France (Cédric Audibert)

CMNC Canadian Museum of Nature Collection, Ottawa, Canada (Robert Anderson, François Génier)

CNC Canadian National Collection of Insects, Arachnids, and Nematodes, Ottawa, Canada (Pat Bouchard)

CNIN Colección Nacional de Insectos, Instituto de Biología, Universidad Nacional Autónoma de México (UNAM), México D. F., México (Harry Alperowitz, Santiago Zaragoza Caballero)

DBPC Denis Bouchard Personal Collection, Autouillet, France

DEPC David Ebrard Personal Collection, Velars sur Ouche, France

DJCC Daniel Curoe Personal Collection, Palo Alto, California, USA

EAPZ Escuela Agrícola Panamericana, Tegucigalpa, Honduras (Ron Cave, Jesús Orozco)

EMEC Essig Museum of Entomology, University of California, Berkeley, California, USA (Cheryl Barr, Peter Oboyski)

FMNH Field Museum of Natural History, Chicago, Illinois, USA (Alfred Newton, Crystal Maier)

FSCA Florida State Collection of Arthropods, Gainesville, Florida, USA (Paul Skelley)

HNHM Hungarian Natural History Museum, Budapest, Hungary (Ottó Merkl)

IAZA Instituto Argentino de Investigaciones de las Zonas Áridas, Mendoza, Argentina (Adriana Marvaldi)

IEXA Colección Entomológica, Instituto de Ecología, A.C., Xalapa, México (Miguel Ángel Morón)

IFML Instituto Fundación Miguel Lillo, Tucumán, Argentina (Dominga Carolina Berta)

IRSNB Institute Royal des Sciences Naturelles de Belgique, Brussels (Alain Drumont)

INBC Instituto Nacional de Biodiversidad, San José, Costa Rica (Ángel Solís)

INPA National Institute for Amazonian Research, Manaus, Brazil (Marcio Luiz de Oliveira)

IREC Institut de Recherches Entomologique de la Caribe, Pointe-a-Pitre, Guadeloupe (also known as Centre de Recherches Agronomiques Antilles Guyana, Duclos, Petit-Bourg [CRAAG] (Girard Chovet, Fortuné Chalumeau)

JEMC José Mondaca E. Personal Collection, Peñaflor, Chile

JPBC Jean-Pierre Beraud Personal Collection, Cuernavaca, Morelos, México

LACM Los Angeles County Museum of Natural History, Los Angeles, California, USA (Brian Brown, Weiping Xie)

MACN Museo Argentino de Ciencias Naturales, Buenos Aires, Argentina (Arturo Roig)

MCZ Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA (Brian Farrell, Naomi Pierce)

MHNN Muséum d’Histoire Naturelle, Geneva, Switzerland (Peter Schwendinger)

MHNP Museo de Historia Natural, Universidad Nacional de San Antonio Abad, Cusco, Perú (Percy Yangue Yucra)

MIUP Museo de Invertebrados “G.B. Fairchild”, Universidad de Panamá, Panamá (Diomedes Quintero Arias)

MIZA Museo del Instituto de Zoología Agrícola, Maracay, Venezuela (José Clavijo)

MLJC Mary Liz Jameson Personal Collection, Wichita, Kansas, USA

MLPA Museo de la Plata, Universidad Nacional de la Plata, La Plata, Argentina (Analía Lanteri, Nora Cabrera)

MLUH Zentralmagazin Naturwissenschaftlicher Sammlungen, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany (Karla Scheider, Joachim Händel)

MNHN Muséum National d’Histoire Naturelle, Paris, France (Olivier Montreuil)

MNNC Coleccion Nacional de Insectos, Museo Nacional de Historia Natural, Santiago, Chile (Mario Elgueta)

MNCR Museo Nacional de Costa Rica, San José, Costa Rica (formerly INBC, Ángel Solís)

MSPC Matthias Seidel Personal Collection, Prague, Czech Republic

MTD Museum für Tierkunde, Dresden, Germany (Klaus-Dieter Klass, Olaf Jäger)

MXAL Miguel Ángel Morón Collection, Xalapa, México

NHMB Naturhistorisches Museum, Basel, Switzerland (Daniel H. Burckhardt)

NMPC Department of Entomology, National Museum (Natural History), Prague, Czech Republic (Jiří Hájek)

OUMNH University Museum of Natural History, Oxford, United Kingdom (Darren Mann, Amoret Spooner)

PAPC Patrick Arnaud Personal Collection, Saintry sur Seine, France

PMNH Peabody Museum of Natural History, Yale University, New Haven, Connecticut, USA (Leonard Munstermann)

PVGH Pedro Vidal Personal Collection, Santiago, Chile

SDEI Senckenberg Deutsches Entomologisches Institut, Müncheberg, Germany (Lothar Zerche, Konstantin Nadein)

STRI Smithsonian Tropical Research Institute, Balboa, Panama (Annette Aiello)

UAEH Universidad Autónoma del Estado Hidalgo, Pachuca, Hidalgo, México (Juan Marquez Luna)

UAG Escuela de Biología de la Universidad Autónoma de Guadalajara, México (Jose Luis Navarette)

UCCC Museo de Zoología, Universidad de Concepción, Concepción, Chile (Jorge Artigas)

UCRC Entomology Research Museum, Department of Entomology, University of California, Riverside, California, USA (Doug Yanega)

UFRJ Museu Nacional, São Cristóvão, Rio de Janeiro, Brazil (Miguel Monné, Marcela Monné)

UVGC Colección de Artrópodos, Universidad del Valle de Guatemala, Guatemala City, Guatemala (Jack Schuster, Enio Cano)

UNSM University of Nebraska State Museum, Lincoln, Nebraska, USA (Brett Ratcliffe, M. J. Paulsen)

USNM U.S. National Museum, Washington, D.C. (currently housed at the University of Nebraska State Museum for off-site enhancement) (Brett Ratcliffe, Floyd Shockley)

UUZM Zoological Institute, Uppsala University, Uppsala, Sweden (Hans Mejlon)

WBWC William B. Warner Personal Collection, Chandler, Arizona, USA

WSU Maurice T. James Entomological Collection, Washington State University, Pullman, Washington, USA (Richard Zack)

ZMHB Museum für Naturkunde der Humboldt-Universität, Berlin, Germany (Manfred Uhlig, Joachim Willers, Johannes Frisch)

ZSMC Zoologische Staatssammlung des Bayerischen Staates, Munich, Germany (Martin Baehr)

Images and terminology . Digital images of type specimens were taken over a 10-year period and were captured using several imaging applications including the Leica Application Suite V3.8. Images were edited in Adobe Photoshop CS2 (background removed, contrast manipulated). Figure legends for type specimens provide the valid, accepted name (as in the catalog) and the original combination of the species. We provide images of type specimen labels, but we largely defer from designating specimens as lectotypes. In our view, this is incumbent upon future revisionary scientists who will observe the best practices of systematics (ICZN 2003) and properly assign type status to specimens based on thorough review of all literature. Morphological terminology follows Hardy (1975) and Jameson (1998). Characters and specimens were observed with 6.3–50.0x magnification and fiber-optic illumination.

Literature reviewed. In compiling this work, we reviewed all available literature including major catalogs (Ohaus 1918, 1934b, Blackwelder 1944, Machatschke 1972, 1974, Smith 2009, Krajcik 2008, 2012, 2013). Some nomenclatural decisions were made by Krajcik (2012), but these were not indicated with “new synonymy” or “new combination,” and the rationale for these changes was not provided. For example, Krajcik did not accept Soula’s concepts of Epichalcoplethis, Chalcoplethis Burmeister, and Sorocha. Instead, he synonymized all names under Pelidnota. Also, Krajcik’s acceptance of names was not homogenous. He included some of Soula’s species and subspecies, but not all of them. For example, from the same publication (Soula 2009), Krajcik included Pelidnota estebanabadiei Soula (2009: 34), but he did not include Pelidnota equatoriana Soula (2009: 32). Krajcik included all of the following names: Pelidnota bondili Soula (2006: 10), Pelidnota castroi Soula (2008), and P. belti boyacaensis Soula (2006: 73), but he did not include any of the following names: Pseudogeniates cordobaensis Soula (2009), Pelidnota brusteli Soula (2010a), P. ohausi piurensis Soula (2006: 22), and P. sanctidomini caliensis Soula (2006: 79). Lacking his rationale, we did not follow Krajcik’s classification for the pelidnotine chafers. We discuss Krajcik’s (2008, 2012, 2013) catalogs to synthesize all available information for pelidnotine scarabs. However, we are agnostic about Krajcik’s listing of generic-, specific-, and subspecific-level synonyms amongst pelidnotine scarab taxa. Krajcik’s catalogs, in our opinion, are useful for tracking data on the proliferation of names in the hyper-diverse Scarabaeoidea, but should not be used to inform classifications. In our generic overviews and annotated catalog, we were forced in most cases to follow Soula’s generic- and species-level classifications (inadequate and uninformative though they are) because they are valid until addressed in broader systematic and revisionary works.

Soula’s descriptions of new taxa were often vague about the number, sex, and associated label data of type specimens. To rectify this lack of basic information, we report the verbatim label data of every pelidnotine scarab type specimen deposited in the Soula collection now housed at CCECL and CMNC. Due to the number of taxa that Soula named and described, both collections are rich in Rutelini type specimens. Among the pelidnotine scarabs, Soula’s material contains over 80 primary types (holotypes and neotypes) and nearly 700 secondary types (allotypes, paratypes, and paralectotypes) that are now all curated at CCECL. Additionally, examination of the CCECL collection revealed Soula specimens with type labels that had not been validly described. These “manuscript names” and the associated specimen data are listed in the appropriate genera (see “Annotated Catalog” below) as in litteris, and they are unavailable names. In a few instances, it appears that Soula omitted paratype data from the original published description or added paratype specimens to a type series after publication of a species description. For example, he added 17 “paratypes” collected in 2011 to Pseudochlorota peruana lecourti (described by Soula in 2005). Soula clearly knew that this violated nomenclatural rules, because he stated: “Répétons que de nombreux “cotypes” de cette Collection ne sont pas de “bons” types car ils ont été désignés et étiquetés après la description originale” (Soula 2005). We report these specimens as “invalid types” or “probable paratypes.” Soula also mislabeled type specimens (holotypes and paratypes), and we noted and corrected these mistakes when possible by referencing Soula’s original species descriptions.

During our study of the Soula collection at CCECL, we were able to return some primary type material to the institutions that had loaned specimens to Marc Soula (Garner and Audibert 2015). This type material had remained in his collection following his death. Additionally, we were able to gather information about what happened to the Soula collection after his passing, but before it was properly and legally accessioned by CCECL. Before CCECL acquired the Soula collection, it was briefly in control of his family. Unfortunately, the scientific value of some specimens was not recognized initially by the family and it seems likely that some material from the Soula collection or loaned specimens (possibly primary types) of an unknown species or several species (described only as a Pelidnota-like species with large legs [possibly some species similar to Pelidnota burmeisteri Burmeister or Chrysina species]) were lost in a sale to an antique collector (pers. comm. from Patrick Arnaud, June 2014) (Garner and Audibert 2015). Future systematists will have to deal with the uncertainty surrounding these possibly lost type specimens. Fortunately, it seems to us that this was an isolated and limited incident. We stress here that this is a cautionary tale that highlights the importance of properly maintaining loan records, providing temporary institutional labels on loaned specimens, and tracking the fate of personal collections that contain type material, regardless of taxonomic group.

Annotated Catalog. We list the author and date of the description of the species and genera, type species of genera (indicated with an asterisk), subspecies and forms, and transfer of species to other genera. This catalog builds on the work of Ohaus (1918, 1934b) and Machatschke (1972, 1974) with additions by Hardy (1975), Soula (1998, 2002a, 2002b, 2003, 2006, 2008, 2009, 2010a, 2010b, 2011), Krajcik (2008, 2012, 2013), and other authors. References to original descriptions of all species and genera are provided. Entries for species in the catalog provide: 1) the valid species name, author, date, and abbreviated citation, 2) original spelling and combination (if applicable), misspellings, new combinations, and invalid names in chronological order, 3) synonyms and the reference in which the synonym was designated, 4) general distribution data including the country (in capital letters) and states/provinces/departments/communes when they are known. Distributions are based on the literature and on specimens that we examined.

Rules of zoological nomenclature. Numerous nomenclatural changes within the pelidnotine scarabs are necessary due to misspellings, invalid type designations, and unavailability of infrasubspecific names (Moore and Jameson 2013, Moore et al. 2014). We follow the International Code of Zoological Nomenclature (ICZN 1999) as a means of stabilizing the taxonomy and classification of the pelidnotine scarabs.

Infrasubspecific names such as varieties and forms were widely used by authors such as Friedrich Ohaus and occasionally Marc Soula. These names are used to indicate unique color variants. Many of these names were treated as forms (forma; infrasubspecific entities) in catalogs (Machatschke 1972, 1974) as well as in works by Soula. According to ICZN Article 45.6.4: “A name is subspecific if first published before 1961 and its author expressly used one of the terms “variety” or “form” (including use of the terms “var.”, “forma”, “v.” and “f.”), unless its author also expressly gave it infrasubspecific rank, or the content of the work unambiguously reveals that the name was proposed for an infrasubspecific entity, in which case it is infrasubspecific” (see Lingafelter and Nearns 2013). Thus, named entities need to be interpreted within the context of the publication to discern if a name was unambiguously infrasubspecific. That is, if the author described or discussed both subspecies and varieties within a work, then it is clear that varieties can be treated as infrasubspecific, thus making the name unavailable unless further action was taken to correct the names prior to 1985 (ICZN Art. 45.6.4.1).

Species for which Soula designated type material but for which specimens are missing and presumed lost resulted in our neotype designations. The International Code of Zoological Nomenclature (ICZN 1999) requires that a neotype “is validly designated when there is an exceptional need and only when that need is stated expressly” (75.3). To be validly designated, Article 75.3.7 (ICZN 1999) requires a statement regarding the accessibility of the specimen. Upon publication, the specimen must be “the property of a recognized scientific or educational institution, cited by name.” Thus, some neotypes were invalidly designated by Soula. Designation of some neotype specimens was necessary for names proposed by Soula.

The lack of synthesis and attention to detail in Soula’s works resulted in some names that were not validly described (see Moore and Jameson 2013, Moore et al. 2014). For all new species-group names described after 1999, the holotype and the type depository must be explicitly stated for the name to be deemed available (ICZN Art. 16.4). Because Soula (2006, 2008, 2009, 2010a, 2011) did not explicitly state the location of holotypes for several species, these names are unavailable.

For groups that have dramatic sexual dimorphism, some taxonomists refer to the “alloréférent” or the “neallotype” specimen for the first specimen of the opposite sex that is described in a publication subsequent to the original description (Dechambre 2001). Unlike name-bearing type specimens (e.g., holotype, lectotype, neotype), these specimens have no formal nomenclatural status (Hawksworth 2010). Soula frequently made use of the term “alloréférent” in his collection and his published works. We stress that these specimens are not name-bearing type specimens.

Poor editing and many misspellings compromise the scientific value of Soula’s works (e.g., scientific names, localities, descriptive characters, figure legends, indices, and identification keys). These errors pose problems because they can be propagated by future researchers. And, in some cases, the error confuses or obscures Soula’s intended species name. We include these misspellings to limit confusion and promote future research.

Type specimens and lectotype designation. For purposes of nomenclatural stability, we designate lectotypes for some species (ICZN Art. 74). In these cases, a specimen was selected among a group of syntype specimens or cotype specimens. During this research (initiated by MLJ in the late 1990s) many type series were studied, lectotype labels added, and specimens returned to museum collections. However, when research on the group became intractable due to Soula’s concurrent work on the group, these lectotypes were not published. Soula also designated lectotypes. In some cases, he removed previous lectotype labels and he changed the collection depository. In other cases, we have reason to reject Soula’s attempted lectotypification. For example, Soula designated paralectotypes without first designating a lectotype (see P. laevissima Burmeister in Soula 2009), he stated that the type series consists of only a holotype but he provided an image of a lectotype (see Homothermon praemorsus (Burmeister) in Soula 2008) and, for a species named by Sharp in 1877, he designated a holotype and paratype (rather than a lectotype and paralectotype) (see P. prolixa Sharp in Soula 2009). All of these cases gave us reason to be cautious of Soula’s lectotypification. Thus, in instances where we have verified label data, we refer to types specifically (lectotype, paralectotype, holotype). In other instances, however, we refer to type specimens as “types,” and we leave lectotype designation to future systematists. We provide images of many type specimens, but it is not our purpose to nomenclaturally fix or designate types with these images.

Concepts for genera and species. In this work, we do not generally assess the validity of species, subspecies, or genera. In our view, this is best conducted as part of comprehensive, revisionary studies. Instead, we provide a taxonomic and nomenclatural framework for future research. Although we do not name new species within this work, we adhere to the phylogenetic species concept (Wheeler and Platnick 2000) in our interpretations: “A species is the smallest aggregation of (sexual) populations or (asexual) lineages diagnosable by a unique combination of character states.” New nomenclatural acts in this work, such as new synonyms and new homonyms, are based on examination of type specimens and in accordance with the rules of zoological nomenclature (International Code of Zoological Nomenclature, 1999).

Hardy’s standards for species circumscription provide a solid basis for ruteline systematics. Hardy’s (1975) classic work on Pelidnota from North and Central America provided the foundation for our knowledge of pelidnotine species as well as a rigorous foundation for interpretation of intraspecific variation. Hardy’s species concepts within the genus Pelidnota have endured for over four decades. Hardy (1975) considered species to be “variable entities” and he allowed for intraspecific variation in coloration, maculae, the degree of posterior coxal corner production, and even the form of male genitalia. Hardy allowed intraspecific variation in parameres in P. punctata (Hardy 1975; Figs 34–36) and P. costaricensis H. W. Bates (Hardy 1975; Figs 38, 39) just to name a few. Because all specimens of all populations of species cannot realistically be studied, actual distributions of characters must be theorized based on available specimens. Species-level lineages are hypothetically circumscribed and these hypotheses should be testable (i.e., subject to the consideration of additional data). Only by examining a large number of specimens and seeing continuity between populations was Hardy (1975) able to conclude that the observed variation was intraspecific rather than interspecific.

In our view, Hardy’s (1975) method of study provided a good test of historical species concepts in Pelidnota as additional specimens and populations were discovered and species boundaries could be critically evaluated (see Wheeler 2004). Critical evaluation of species boundaries is an important (but largely undiscussed) concept within pelidnotine leaf chafer taxonomy due to the elaborate male genital morphology (considered diagnostic for identification) present in many species. Pelidnotine scarab species, and Rutelini more generally, often have asymmetric parameres and ventral genital plates originating from the phallobase (e.g., in the genera Homothermon, Xenopelidnota F. Bates, and many Pelidnota). The cuticular generation of these asymmetric structures is certainly a complex and highly sensitive developmental process that we think gives rise to a great deal of intraspecific variation in male genital characters. Many historical Pelidnota workers, outside of Hardy (1975), have interpreted this type of genital shape variation to be interspecific and subsequently split species where we may have lumped them into broader, variable species.

In contrast to Hardy’s (1975) and our species concept, Soula’s species concept (1998, 2002a, b, 2003, 2006, 2008, 2009, 2010a, b, 2011) did not allow for intraspecific variation. In Soula’s works, slight differences in color, punctation, or form of male parameres equated to different species or subspecies. In fact, slight differences in male parameres could be attributed to minor deviation in the manner in which parameres were viewed. For example, Soula’s description of S. purpurea esperitosantensis was based on two male specimens from Espírito Santo, Brazil (Soula 2006). Soula’s line drawings of the male parameres are extremely similar to the nominate subspecies, and Soula remarked that parameres of both were “slightly different.” Both the nominate species and subspecies were known to Soula from fewer than five specimens in total, and only the nominate form of the species was included in Soula’s key (2006: 9-12).

In the pelidnotine scarabs, Soula (2006, 2008, 2009, 2010a, 2011) described over 150 new species and subspecies and ultimately classified approximately 100 new species and subspecies in Pelidnota. Quantifying the number of specimens that Soula’s pelidnotine species-group names were based upon illustrates the lack of intraspecific variation incorporated into his species concept. Forty-four percent (67 of 152) of Soula’s new species and subspecies of pelidnotine scarabs were described from two (minimum number for both sexes to be described) or one specimen. Approximately 33% (50 of 152) of Soula’s new pelidnotine names were based on descriptions of a single, male holotype specimen. In total, 41% (63 of 152) of Soula’s new pelidnotine names were based upon descriptions of only one sex. Soula’s species and subspecies concepts were almost singularly reliant on slight differences in male paramere morphology and/or broadly separated populations. These concepts, when paired with the limited number of specimens of some genera to which he had access, led to his inability to reliably diagnose species when either of these conditions was violated. For example, Soula stated that he could not diagnose the females of Sorocha Soula species when they are even narrowly sympatric. For example, for diagnosis of “S. yelamosi” Soula stated (2011: 82), “Là encore la femelle est à capturer et à repérer. Plusieurs espèces semblent cohabiter et il ne sera pas facile d’appareiller les couples”. In sum, adequate characters were not provided to circumscribe many of Soula’s species-level hypotheses. Soula’s guides provided the outlet for description of many new genera, species, and subspecies, but an adequate concept that guided his hypotheses was lacking. In our view, Soula’s species and subspecies concepts cast doubt on the validity of many of his taxa.

DNA barcode analysis for Pelidnota punctata. Cytochrome Oxidase 1 (CO1) DNA data were used to address genetic variation in Pelidnota punctata across the distributional range of the species. Using the Barcode of Life Database (BOLD: http://www.boldsystems.org), CO1 data were gathered for P. punctata (13 specimens) and 10 other species of Pelidnota (38 specimens). The distance model used the Kimura 2 parameter with a neighbor-joining tree building method in BOLD. Nodes are labeled by species name, BOLD ID number, and country and state/province where the specimen was collected (Fig. 4).

Overviews of genera. Biological and natural history data in the “Generic Overviews” were synthesized from the literature, specimens, and specimen labels from many institutions. Overviews do not summarize all literature and all specimens. Instead, they highlight: 1) potential complications such as paraphyly and nomenclatural issues, 2) potential synapomorphic characters and discuss possible sister-group relationships, 3) basic distribution and habitat affiliations, and 4) known larvae and natural history information.

Key to the genera of pelidnotine scarabs (Coleoptera, Scarabaeidae, Rutelinae, Rutelini)

Males: inner protarsal claw wider than the outer claw; may or may not possess a small, inner tubercle; sternites usually concave. Females: protarsal claws similar in width; lack a small, inner tubercle; sternites usually convex.

1	Claws on all legs simple and of similar size; protarsal claw (male) lacking apical or subapical tubercle, lacking apical split	Neogutierrezia Martínez
–	Claws on all legs with the inner claw different than the outer claw (wider or split apically); protarsal claw (male) wider than outer claw, with or without small, inner tubercle, and with or without apical incision	2
2	Labrum and clypeus fused anteriorly	Peruquime Mondaca and Valencia
–	Labrum and clypeus not fused anteriorly, free	3
3	Lateral edge of mandible lobe-like and flattened, without reflexed teeth (e.g., Fig. 1A)	4
–	Lateral edge of mandible not flattened, with 1 or 2 reflexed teeth (Fig. 1B, C, E, F)	8
4	Apex of labrum extends beyond clypeal apex, visible from dorsal view	5
–	Apex of labrum does not extend beyond clypeal apex, not visible from dorsal view	6
5	Metatarsomere 4 at apex with 4-6 spinules, medial spinules thickened	Oogenius Solier
–	Metatarsomere 4 at apex with 4-6 spinules, medial spinules seta-like (not thickened)	Microogenius Gutiérrez and Eremophygus Ohaus
6	Clypeus with apex quadrate or subquadrate (Fig. 1D); apex emarginated	7
–	Clypeus with apex rounded, parabolic, or trapezoidal; apex with or without emargination (Fig. 1A, B, C, E, F)	8
7	Lateral edge of protibia with 2 teeth	Chipita Soula
–	Lateral edge of protibia with 3 teeth	Parhoplognathus Ohaus
8	Apex of elytra in males with acute, spiniform projections (Fig. 3C, D)	9
–	Apex of elytra in males rounded	10
9	Males without acute process on posterior margin of mesofemur. Females with 2 deep emarginations near the apex of the terminal sternite; pygidial disc with a concavity. Dorsal color metallic green	Hoplopelidnota F. Bates
–	Males with acute process on posterior margin of mesofemur (Fig. 2E). Females lacking emarginations at apex of terminal sternite, instead apex is rounded; pygidial disc convex. Dorsal color testaceous or light-brown (with or without weak metallic-green reflections)	Mesomerodon Ohaus
10	Pronotum with apical bead obsolete or lacking medially (Fig. 1A)	Chrysina Kirby
–	Pronotum with apical bead complete medially (Fig. 1B, C, D, F)	11
11	Males with metatibia enlarged, curved, produced posteriorly at apex	Chrysophora Dejean
–	Males without metatibia enlarged, curved, produced posteriorly at apex	12
12	Metatarsomeres 1–5 longer than metatibia	Chalcoplethis Burmeister
–	Metatarsomeres 1–5 subequal to metatibia	13
13	Metatibia somewhat laterally flattened (Fig. 2A)	Epichalcoplethis F. Bates
–	Metatibia not laterally flattened (Fig. 2B)	14
14	Prosternal projection (between procoxae) produced to level of procoxae	15
–	Prosternal projection (between procoxae) shorter, not produced to level of procoxae Xenopelidnota F. Bates
15	Base of metatibia with semicircular notch (Fig. 2C)	Mecopelidnota F. Bates
–	Base of metatibia lacking semicircular notch, straight (Fig. 2D)	16
16	Apex of metatibia straight and with numerous spinules	Ectinoplectron Ohaus
–	Apex of metatibia not straight (biemarginate or with external apex produced), with 0–8 spinules	17
17	Metatibia lacking produced external apex, lacking apical spinules	18
–	Metatibia with external apex produced posteriorly and with apical spinules	26
18	Disc of frons with weak V-shaped depression (Fig. 1E)	Sorocha Soula
–	Disc of frons planar, smooth, lacking a V-shaped depression (Fig. 1A, B, C, D, F)	19
19	Metatibia laterally flattened	20
–	Metatibia not laterally flattened	21
20	Metatarsomeres 1-5 subequal to metatibia	Epichalcoplethis F. Bates
–	Metatarsomeres 1-5 longer than metatibia	Chalcoplethis Burmeister
21	Elytral shoulder rounded (not flat in ventral view), lacking bead	Homothermon Ohaus
–	Elytral shoulder flat in ventral view, with bead	22
22	Mesometasternal keel surpassing mesocoxae (Fig. 3B)	Pelidnota MacLeay
–	Mesometasternal keel not surpassing mesocoxae (Fig. 3A)	23
23	Lateral edge of mandible with two reflexed teeth (Fig. 1B, E, F)	24
–	Lateral edge of mandible with one reflexed tooth (Fig. 1C)	25
24	Metatarsomere 3 with apical setae (externally) of unequal length and width; color castaneous to black	Homonyx Guérin-Méneville
–	Metatarsomere 3 with apical setae (externally) of equal length and width; color metallic green	Catoclastus Solier
25	Fifth meso- and metatarsomeres without internal teeth, tarsomeres simple	Pseudogeniates Ohaus
–	Fifth meso- and metatarsomeres with one or two internal teeth (may be rounded)	Parhomonyx Ohaus
26	Protibia with 2 external teeth	Pachacama Soula
–	Protibia with 3 external teeth	27
27	Labrum with apex bilobed	Patatra Soula
–	Labrum with apex projecting anteriorly at middle, not bilobed	Homeochlorota Soula

Figure 1.

Clypeal shape varying from rounded, parabolic, trapezoidal, subquadrate (A–D), and emarginate (E–F). Lateral edge of mandibles with no reflexed teeth (lacking teeth in A, but the mandible is reflexed rather than flattened in A, two reflexed teeth (B, E, F), or one reflexed tooth (C)). Apical bead of pronotum varying from obsolete (A) to complete medially (B, C, D, F). Disc of frons with V-shaped depression (E) or frons planar, smooth, lacking V-shaped depression (A–D, F) A Chrysina beyeri Skinner B Epichalcoplethis velutipes velutipes (Arrow) C Parhomonyx fuscoaeneus (Ohaus) D Chipita mexicana (Ohaus) E Sorocha sp. F Homonyx elongatus (Blanchard).

Figure 2.

Characters of the mesofemora and metatibiae in pelidnotine genera. A Epichalcoplethis aciculata (F. Bates), metatibia somewhat flattened (dorsal view) B Pelidnota virescens, metatibia not flattened (dorsal view) C Mecopelidnota sp., metatibia at base with a semicircular notch D Pseudogeniates cordobaensis Moore et al., metatibia simple at base E Mesomerodon gilletti Soula male, acute production of posterior margin of mesotibia (ventral view).

Figure 3.

Characters of the thorax (ventral view) and elytral apex (dorsal and lateral views). Mesosternal keel not surpassing base of mesocoxae (A) or keel surpassing base of mesocoxae (B). Acute, spiniform projections at apex of elytra (C, D). A Homonyx elongatus B Pelidnota dobleri Frey C Mesomerodon gilletti, dorsal view D Mesomerodon gilletti, lateral view.

Pelidnota punctata (Linnaeus) species hypothesis and synonyms

Pelidnota punctata (Linnaeus) is a widespread species in North America occurring from Ontario and Quebec to Florida west to South Dakota and Texas. The host plant of this species is grape (Vitis Linnaeus; Vitaceae) foliage and fruit and the larvae develop in rotting stumps and logs of various deciduous trees.

The taxonomic history of this species dates back to the very beginning of zoological binomial nomenclature with a brief description by Linnaeus (1758) (as Scarabaeus punctatus), followed by more extensive (and quite sufficient) descriptions in later editions of Systema Naturae (Linnaeus 1764, 1767). The locality was erroneously given as “India” (Linnaeus 1758, 1764), but was later corrected to “Carolina” (Linnaeus 1767). The photograph of the Linnaeus lectotype specimen leaves no doubt about the identity of this species (Fig. 79). The lectotype is formerly of the Ludovicae Ulricae collection, which is now housed in the Zoological Institute in Uppsala University, Sweden (UUZM).

Melolontha lutea Olivier, 1789 was later described, but it has since been recognized that Olivier (1789) was describing the lighter colored and non-spotted southeastern United States version of this same species (see Hardy 1975 for a detailed discussion). Casey (1915) has the unfortunate notoriety of describing a further 10 synonyms of P. punctata based largely on intraspecific color variations in this species. Hardy (1974, 1975) synonymized all of these Casey names during the course of his taxonomic revision of the genus Pelidnota. Hardy (1975) gave a good account of the color variation of P. punctata and detailed a north-south cline of variation. We have observed that specimens from Canada and the northern United States always have dark legs and clearly defined spots (six on the elytra and two on the pronotum) while the legs and spots can be much lighter in specimens from the southern United States. We have observed that many specimens from Florida and Texas have light legs and little to no trace of spots on the pronotum or elytra. Considering the scope of the variation, even within smaller regions, we postulate that larval diet/nutrition, environmental conditions during development, and the length of time spent in the larval stage can have a significant impact on color patterns along with genetics for this particular species. Ritcher (1966) stated that in Lexington, Kentucky, P. punctata pass the winter in the larval stage and appear to have a two-year life cycle. It is possible that the life cycle of this species is accelerated in the southern part of the range. Pelidnota punctata may have an extended life cycle in the northern part of the range in response to decreased temperature and more extreme seasonal climate fluctuation.

Pelidnota genieri Soula was described as a purported species endemic to Ottawa, Ontario, Canada (Soula 2009). Soula’s (2009) description was based on color patterns and trivial structural characters without any detailed comparisons with P. punctata specimens from other parts of Canada and North America. We studied the holotype, allotype, and ten paratypes (five males, five females) from Soula’s type series and have concluded that the color patterns observed are well within the range of variation observed from specimens of P. punctata from other parts of Ontario, Quebec, and across the eastern half of the United States (over 500 specimens were examined). In fact, the holotype, allotype, and two paratypes were from a larger series of 51 specimens from the same collecting event (Ottawa, ONT. / 5. VIII.1971 / J.E.H. Martin) all in the Canadian Museum of Nature Collection. Having seen only four of the 51 specimens from this collecting event, Soula was unaware that the color variation observed in this series alone undermined many of the characters used to justify his new species (varying shades of dorsal coloration, different sizes of dark spots, different amounts of metallic green reflections around and between the eyes). Therefore, we are placing Pelidnota genieri in synonymy with Pelidnota punctata (syn. n.).

Soula’s (2009) motivation for describing such an obvious synonymy is unclear, but the quality of his work is highly suspect in our opinions after using his publications and examining material identified and described by him in the Canadian Museum of Nature collection and CCECL. Since Marc Soula’s death in 2012, his taxonomic work has come under increased scrutiny and criticism for poor quality (e.g., Moore and Jameson 2013, Garner and Audibert 2015). A case in point relevant to Pelidnota genieri was the fact that Soula (2006) had previously described Strigidia genieri Soula, 2006, and then he transferred this species to Pelidnota (in Soula 2009), creating a secondary homonym with the Pelidnota genieri in the very same paper where the former name was described! Moore and Jameson (2013) fixed this homonymy problem by erecting Pelidnota francoisgenieri Moore & Jameson, 2013 as a replacement name for Pelidnota genieri Soula, 2009 (not Pelidnota genieri [Soula, 2006]). As an objective synonym of Pelidnota genieri, Pelidnota francoisgenieri is also here placed in synonym with Pelidnota punctata (syn. n.).

Soula (2009) also re-validated the names Pelidnota lutea (Olivier) and Pelidnota texensis Casey from synonymy with Pelidnota punctata for the Florida and Texas populations, respectively. He discussed some morphological differences between these populations and pointed out some variations in the male genitalia but also remarked that a DNA analysis would be necessary to determine the classification of this group of species. While we acknowledge that there are some morphological differences, we do not see stable and consistent differences between the populations or forms of P. punctata enough to warrant splitting this species at this time. DNA barcoding data is available for specimens from Ontario, Florida, Arkansas, and Texas (Fig. 4). Based on the lack of consistent morphological differences and the virtually identical CO1 barcoding data for specimens from the northern and southern extremes of the distribution, we hereby reinstate the junior synonymy of both Pelidnota lutea and Pelidnota texensis with Pelidnota punctata.

Figure 4.

Neighbor-joining tree for individuals of P. punctata across the species’ distribution based on CO1 data. Between-species divergence is typically above 10% (e.g., P. punctulata and P. strigosa), whereas within species divergence is typically less than 1% (e.g., P. punctata and P. lugubris).

In the genus Pelidnota, analysis of the CO1 barcode data (Fig. 4) shows that between-species divergence is typically more than 10% (e.g., P. punctulata and P. strigosa). In contrast, the CO1 barcode region typically shows less than 1% divergence within species (e.g., P. lugubris), even when the individuals are separated by more than 200 miles (Sonora, Mexico to Arizona, USA). Similarly, individuals of P. punctata that were collected from across the species’s range (Florida, USA to Ontario, Canada) showed less than 1% CO1 divergence (mean: 0.24 % infraspecific divergence; max: 0.77 % infraspecific divergence). Individuals of Pelidnota punctata from Ontario, Canada (in the northern extent of the distribution) possess dark metallic green elytral spots, legs, and venter. Some individuals from Florida, USA (in the southern extent of the distribution) possess reduced elytral spots or no elytral spots and possess tan legs and venter. The CO1 data demonstrate that these phenotypic differences are not strong characters for species cohesion and provide support that all morphotypes of P. punctata are, in fact, conspecific (see “Annotated Catalog” for synthetic taxonomic information of P. punctata and synonyms).