Three new species of the genus Chilocorellus Miyatake (Coleoptera, Coccinellidae, Sticholotidini) from the Philippines

Abstract The genus Chilocorellus Miyatake, 1994 has been revised. Three new species (C. uncinacanthus Zhang & Wang, sp. nov., C. denspinulifer Zhang & Wang, sp. nov., and C. fistulachaetodontus Zhang & Wang, sp. nov.) from the Philippines are described and illustrated in the present paper. An updated key to the species of the genus Chilocorellus is provided. In addition, a list of all known species and their distributions is also provided.


Introduction
The subfamily Sticholotidinae was recognized by Weise (1887) in the modern sense as a peculiar group of the family Coccinellidae. It has been used to accommodate small or very small ladybird beetles in which the form of the terminal maxillary palpomere is not securiform and is elongate conical or apically acuminate (Gordon 1977(Gordon , Ślipiński 2004. Gordon (1977) and Hoàng (1982) used Sticholotidini after "Sticholotini" was first-used by Weise (Weise 1887(Weise , 1901. Miyatake (1994) revised the subfamily Sticholotidinae from Asia and established six new genera (Synonychimorpha, Chilocorellus, Sulcolotis, Filipinolotis, Mimoserangium, and Coelolotis) in the tribe Sticholotidini.
Chilocorellus Miyatake, 1994 was described from Luzon, Philippines with C. luzonicus as the type species. Subsequently three new species (C. quadrimaculatus, C. protuberans, and C. tenuous) from China were described by Wang and Ren (2010). In 2011, another species (C. seleuyensis) from Laos was added to this genus by Wang and Ren. The molecular phylogenetic analyses revealed no significant support for the tribe Sticholotidini (Giorgi et al. 2009;Magro et al. 2010;Seago et al. 2011;Robertson et al. 2015) and Sticholotidini was placed into an expanded concept of Coccinellinae (Escalona and Ślipiński, 2012;Ślipiński, 2007). The taxonomic status of the genus Chilocorellus has changed. Seago et al. (2011) investigated the phylogeny and evolution of the Coccinellidae based on the combination of molecular and morphological data. Their results showed that Chilocorellus was embedded in the tribe Chilocorini and recovered as the sister group of Chilocorus. They transferred Chilocorellus from Sticholotidini to Chilocorini. Recently, Li et al. (2020) reconstructed the phylogeny of the tribe Chilocorini. The results indicated that the two unidentified specimens of Chilocorellus were forming a single branch. However, they excluded Chilocorellus from Chilocorini as it was recovered far from this tribe based on combined molecular and morphological data analyses.
In this study, examination of ladybird specimens from the Australian National Insect Collection revealed that three species belong to this genus and they are described herein as new to science.

Materials and methods
The specimens of the new species were collected from Luzon, Philippines. All examined materials are preserved in the Australian National Insect Collection, CSIRO, Canberra, Australia (ANIC) and the Insect Collection of South China Agricultural University, Guangzhou, China (SCAU). External morphology was observed with a dissecting stereoscope (Zeiss Discovery. V20). The following measurements were made with an ocular micrometer following Wang et al. (2017): total length (TL), length from apical margin of clypeus to apex of elytra; total width (TW = EW), width across both elytra at widest part; height (TH), from the highest part of the beetle to elytral outer margins; head width (HW) in a frontal view, widest part including eyes; pronotal length (PL), from the middle of anterior margin to the base of pronotum; pronotal width (PW) at widest part; elytral length (EL), along the suture, from the apex to the base including the scutellar shield; eyes width (Eye W) in a frontal view.
Images were taken with digital cameras (ZEISS Imager M2 and Axiocam 506 Color) connected to a dissecting microscope. The software ZEN 2.3 was used to capture images from the cameras. And Adobe Photoshop CC was used to clean up images. The distribution map was downloaded from a free map website (http://alabamamaps.ua.edu).
Terminology follows Ślipiński (2007) and Ślipiński and Tomaszewska (2010). Type specimens designated in the present paper are deposited in ANIC.
Distribution. China, Indonesia, Laos, Philippines (Fig. 4). Diagnosis. This species is similar to C. protuberans, C. tenuous, and C. seleuyensis in general appearance (e.g., the elytra yellow without any spots and broad), but can be distinguished from them by the anterior part and apex of penis hatchet-shaped with irregularly serrated coupled teeth. In C. protuberans, the penis is long and slender, with a large penis capsule and apex of penis is curved, with many small teeth. In C. tenuous, penis is very long and slender and apex of penis has many large teeth. In C. seleuyensis, penis is longer than in other species and apex of penis is partly membranous, with many small teeth. Head yellow, with eyes silvery gray. Pronotum, scutellar shield, and elytra yellow, with small dense punctures. Underside yellow, except mesoventrite and metaventrite yellowish brown.

Distribution. Philippines (Davao).
Etymology. The name uncinacanthus is composed of the Latin word uncin, which refers to the anterior part of uncinate penis and acantha, referring to the anterior part and apex of the penis. Holotype. Philippines: 1 male, Puerto Princesa, Palawan Is, sea level, secondary growth forest, IV 47.

Chilocorellus denspinulifer
Paratype. 1 female, Philippines, Puerto Princesa, Palawan Baker. Diagnosis. This species is similar to C. uncinacanthus, C. protuberans, C. tenuous, and C. seleuyensis by the strongly convex, yellow elytra having no spots. But unlike these species, its body is small, the anterior and apex of the penis is tubular with irregular dense tiny teeth. In C. uncinacanthus, the apex of the penis is hatchet-shaped and bears large teeth; in C. protuberans, the apex of the penis is curved and membranous, with many small teeth; in C. tenuous, the apex of the penis is straight and membranous, with many asymmetrical large teeth. Head yellow, with eyes silver-gray. Pronotum, scutellar shield, and elytra uniformly yellow, with tiny dense punctures. Underside yellow; prosternum, mesoventrite, metaventrite, and legs yellowish brown. Body rounded, strongly convex (Fig. 2b, c). Head small, 0.32 times elytral width (HW/ TW = 1:3.2), with sparse pubescence. Eyes oval, widest interocular distance 0.37 times head width (eye W/HW = 1:2.7). Frons broad, punctures uniform and dense (Fig. 2c, d).
Distribution. Philippines (Puerto Princesa). Etymology. The name denspinulifer is composed of the Latin word dens, meaning dense, and spinulifer, which refers to the part of the penis with spinulose appendage. Diagnosis. This species can be distinguished from the other species of the Chilocorellus by following characters: body is small; elytra are black with just yellow margin; apex of penis guide with a membranous triangular prominence; penis long, anterior part and apex of penis with teeth, and apex of penis simple.

Distribution. Philippines (Luzon).
Etymology. The name fistulachaetodontus is composed of the word fistula, which refers to the penis shape, and chaetodontus, which refers to the anterior part and apex of penis with irregular short, dense teeth.
An updated key to the species of Chilocorellus Miyatake