Aroid scarabs in the genus Peltonotus Burmeister (Coleoptera, Scarabaeidae, Dynastinae): key to species and new distributional data

Abstract The southeast Asian scarab beetle genus Peltonotus Burmeister (Scarabaeidae, Dynastinae, Cyclocephalini) is reviewed. New country records for Peltonotus morio Burmeister (Myanmar and Vietnam), Peltonotus nasutus Arrow (southern China and Cambodia), and Peltonotus favonius Jameson and Wada (Myanmar) are reported, including a new record in the Palearctic/Sino-Japanese biogeographic region. The first female specimen of Peltonotus favonius is described. Biological associations with aroid inflorescences are reviewed, and human consumption of Peltonotus beetles is reported. A key to all species, paralectotype designations for Peltonotus nasutus, diagnoses, and distributions using dynamic mapping tools are included.


Introduction
The scarab beetle genus Peltonotus Burmeister (Scarabaeidae, Dynastinae) includes 25 species that are distributed in forest habitats in Southeast Asia and that are associated with aroid inflorescences (Araceae) . Adult beetles use inflorescences as sites for mating and feeding, and they serve as pol-linators (Moore and Jameson in press, Maia et al. 2012). Species in the genus are intimately tied to host aroids and their forest habitats, and we predict that many species await discovery. Members of the genus form a natural group based on a unique, articulated maxillary tooth. The first monograph for the genus  included 19 species; since this time, six additional species have been described (Jameson andWada 2009, Jameson andJakl 2010), a 30% increase in species diversity.
Identification of species in the genus Peltonotus is hampered by sexual dimorphism that makes association of conspecific sexes difficult, absence of male or female specimens for some species, rarity of some species (perhaps due to brief activity patterns and host plant phenology), and color variability within species. For this reason, we amalgamate existing keys into one identification guide for males and females and provide diagnoses.
Species of Peltonotus are associated with aroid inflorescences (Araceae) . However, in comparison to the abundant research on aroid and scarab beetle interactions in the New World tropics (e.g., Gibernau et al. 2010;Maia et al. 2012;Young 1988), little research is being conducted on Peltonotus and aroids in the Old World. Peltonotus malayensis Arrow is associated with inflorescences of the climbing aroid, Epipremnum falcifolium Engl. (Araceae) . Male and female beetles (as well as many small beetles and arthropods) have been reported around the base of the spathe where adult P. malayensis were observed mating and feeding. Inflorescences of the cultivated aroid, Amorphophallus paeoniifolius (Dennst.) Nicolson (Araceae), attract aggregations of Peltonotus nasutus Arrow (Grimm 2009). This plant (also called the elephant foot yam or corpse plant) grows on the forest floor in dappled shade or in the open sun in secondary forest or highly disturbed areas. The large flower (up to 40 cm) smells like a rotting dead animal and deceptively attracts insects that may serve as pollinators (Schiestl and Dötterl 2012) including the carrion scarabs Phaeochrous dissimilis Arrow, Ph. emarginatus Laporte, and Ph. intermedius Pic (all Scarabaeoidea, Hybosoridae), and the aroid scarab P. nasutus (Grimm 2009). Additional research on aroids and Peltonotus species is needed in order to clarify plant-insect interactions including evolution, ecology, and pollination.
In addition to being associated with aroid inflorescences, adults are attracted to lights at night, and some have been collected in malaise traps. Adults may have short seasonal activity patterns. Some adults have been recorded for only two nights during season-long, intensive collecting efforts. Larvae are not known for any species in the genus.
Survey efforts and collecting in Southeast Asia have provided new distributional data for species in the genus, thus yielding a clearer understanding of distribution patterns. Herein, we report new distributional data for three species of Peltonotus. Because identification of species requires use of three publications , Jameson and Wada 2009, Jameson and Jakl 2010, we provide a comprehensive key to all species in the genus, short diagnoses, new paralectotype designations for P. nasutus, and maps with associated files for dynamic mapping capabilities.

New distributional records, human consumption, and paralectotype designations for Peltonotus nasutus
Peltonotus nasutus ) is the most distinctive species within the genus Peltonotus due to its large body size (~20 mm), tubercle at the apex of the clypeus in the male (Fig. 23), and greatly enlarged protibial claw in the male (Fig. 52).
Large aggregations of adults (over 100) have been found in association with the large, fetid-smelling aroids in the genus Amorphophallus (Grimm 2009; label data at BMNH). In Thailand, the stench of flowering A. paeoniifolius attracts a profusion of P. nasutus individuals that serve to pollinate the inflorescence. Seventy eight specimens were recorded in one flower, and these were collected, fried with fish sauce and salt, and then consumed by the Karen-speaking tribe in the Tak province in northern Thailand (Danell 2010). Thai people consume more insects per capita than other people and cultures (Chen et al. 1998), and this beetle species is a new record for human consumption.
The species is distributed in Myanmar, Thailand, Laos, and Vietnam (Jameson and Wada 2004;Li et al. 2012) (Fig. 92). Adults inhabit deciduous dipterocarp forests between 100-800 m elevation and have been collected at mercury vapor light traps. Examination of additional specimens provided new country records for P. nasutus in Cambodia and China. This species was not previously recorded as occurring in the Palaearctic region (as defined by Löbl and Smetana 2003). These records demonstrate that the species occurs in the Guangxi and Guizhou provinces of southern portion of China in what is considered the Palaearctic biogeographic region (Löbl and Smetana 2003) or the Sino-Japanese biogeographic region (Holt et al. 2013). New Country Record: CHINA (6 males, 2 females deposited in Drumont Collection; AREC): Guangxi Zhuang Autonomous Region (Guangxi), Guizhou (Weining, Mt. Ping-Qing-Liang-Zi), Yunnan (Jinggu, Mt. Longtanshan; Menglian, Mt. Daheishan). Specimens were collected from May to July: May (1), June (3), July (4). New Country Record: CAMBODIA (9 males, 12 females deposited at IRSNB): Pursat (Phnom Samkos Wildlife Sanctuary), Ratanakiri (Phumi Kalai Thum), Pailin (Pailin). Specimens were collected from April to June and November: April (3), May (2), June (3), November (13). The new country record in Weining, China extends the known range of the species over 600 km north.

New distributional records and description of first female specimen for Peltonotus favonius
Peltonotus favonius Jameson and Wada (Fig. 4) was previously known based only on one male specimen from Vietnam (Jameson and Wada 2009). This species is most similar to P. pruinosus, a species for which only the female holotype is known. The discovery of additional male specimens and the first female specimens facilitates identification of the species, expands the characteristics of the species, and broadens our understanding of the distribution of the species. New Country Record (2 male and 2 female specimens deposited in MLJC): MYANMAR, Mt. Nweezin, ~750m, 10 km NNE of Puta-o, North Kachin, June 16-21, 1998. The new record extends the known range of the species over 2000 km from Vietnam to Myanmar. Specimens were provided by Shinji Nagai. Male specimens from Myanmar (n=2) possess black and reddish-brown elytra (the holotype specimen from Vietnam possessed black elytra). Female specimens (n=2) differ from the male specimens in the following respects: Color: Head, pronotum, scutellum, propygidium, pygidium, and venter shining black; elytra black or dark reddish-brown with iridescent bloom. Elytron: Epipleuron in ventral view (Fig. 75) broadly expanded from base to apex of metacoxa, weakly convex, not incised at apex, with sparse, setose punctures, setae reddish, moderately long; in dorsal view expansion not developed (lacking dorsal pillow), instead with concave groove adjacent to epipleuron. Propygidium: Surface moderately densely punctate; punctures simple and ocellate, mixed, not setigerous. Pygidium: Surface moderately densely punctate; punctures simple and ocellate, not setigerous. Legs: Protibia tridentate. Proclaws of female 3/4 length of protarsomere 5, claw angled ventrally.

New distributional records for Peltonotus morio
Peltonotus morio Burmeister (Fig. 12) is the type species for the genus Peltonotus and is one of the most wide-spread species in the genus (Fig. 92). It is distinguished from its close congener, P. nasutus Arrow (Figs 14-15), by its incomplete pronotal basal bead (complete in P. nasutus), form of the male parameres (Figs 65-66), lack of a small tubercle at the apex of the clypeus in the male ( The species is found in northeastern India, Nepal, Bhutan, and Thailand (Jameson and Wada 2004). It can be collected at lights (Dhoj et al. 2009). Within the Palearctic region (Löbl and Smetana 2003) or Sino-Japanese region (Holt et al. 2013), it is the only recorded species of Cyclocephalini (Dynastinae), and it was recorded from Bhutan, Nepal, and Sikkim (Krell 2006). Examination of additional specimens provided new country records for P. morio in Myanmar and Vietnam. New Country Record: MYANMAR (2 specimens deposited in FUJI): Tanintharyi (near Tenasserim), May-1992, 1 male; Mt. Dawna, May-1992, 763 m elevation, 1 female. New Country Record: VIETNAM (1 specimen deposited in IRSNB): Lào Cai Province, June 10, 1917, 1 male. Despite the antiquity of the specimen (nearly 100 years old), the new record in Vietnam extends the known range of the species over 600 km from northern Thailand to northern Vietnam. Based on these distributional data, P. morio and P. nasutus may be narrowly sympatric in southern Myanmar and Thailand.

Distribution. Vietnam and Myanmar.
Remarks. This species is most similar to P. pruinosus, a species for which only the female holotype is known. Previously, this species was only known from the male holotype specimen from Vietnam.

Remarks.
Peltonotus mushiyaus is the smallest species in the genus. We hypothesize that males of this species will possess orangish-tan elytra with castaneous maculae, similar to males of P. vittatus.

Distribution. Malaysia (Peninsular Malaysia).
Remarks. Peltonotus podocrassus and P. gracilipodus (distributed in Sumatra) are similar with respect to the male parameres and female epipleura. This may be indicative of recent divergence from a common ancestor.