﻿Two new species of Metapocyrtus (Orthocyrtus) Heller, 1912 (Coleoptera, Curculionidae, Entiminae) from southern Mindanao, Philippines, with ecological notes

﻿Abstract Two new species of the genus MetapocyrtusHeller, 1912,subgenusOrthocyrtus Heller, 1912 are described and illustrated from southern Mindanao, Philippines: M. (O.) melibengoysp. nov. and M. (O.) flomloksp. nov. Another two species were transferred from the subgenus Artapocyrtus Heller, 1912 to Orthocyrtus, namely, M. (O.) willietorresi Cabras & Medina, 2018 and M. (O.) villalobosaePatano et al., 2021. Ecological notes are provided.


Introduction
Members of the subgenus Orthocyrtus Heller, 1912(genus Metapocyrtus Heller, 1912 are among the most notable of the tribe Pachyrhynchini for their conspicuously large size. The subgenus is currently recognized as endemic to the Philippines and is distributed all over the archipelago. Up to the present, the subgeneric division of Metapocyrtus is uncertain and badly needs revision. However, members of Orthocyrtus have distinct and stable characters that distinguish them from other subgenera: 1) large species, with a few exceptions; 2) rostrum of medium length, dorsally straight, mostly in a plane with the front (exceptionally slightly concave) and at the base, the sides are rectangularly declined; 3) female, with a few exceptions, without any secondary sexual structural characters aside from a stouter form, and similar to the male; (Schultze 1925;Cabras et al. 2018). The biology and ecology of the genus remain understudied; however, members of the subgenus can be found in a range of habitats which include lowland coconut farmlands, mid-elevation between 300-800 m in mixed secondary forest, as well as old-growth primary and secondary forests (Cabras et al. 2018;Cabras and Medina 2019;Cabras et al. 2021a, b).
In the past two years, two species belonging to Orthocyrtus were collected from southern Mindanao and found to be new to science. In this paper, the two new species are described and illustrated. Short notes on their ecology are provided. Another two species from the subgenus Artapocyrtus Heller, 1912 were transferred to Orthocyrtus,

Materials and methods
The specimens deposited in the University of Mindanao Coleoptera Research Center were collected by sheet beating and handpicking and killed in vials with ethyl acetate. Morphological characters were observed under Luxeo 4D and Nikon SMZ745T stereomicroscopes. The treatment of the genitals follows Yoshitake (2011). Anatomical parts of the female genitalia are not illustrated as very little of the chitinous structures are used to identify and characterize different species of Pachyrhynchini (Cabras et al. 2021a). Images of the habitus were taken using a Nikon D5300 digital camera with a Sigma 18-250 macro lens. Images were stacked and processed using a licensed version of Helicon Focus 6.7.0, then contrast adjusted in Photoshop CS6 Portable software. Label data are indicated verbatim.
Abbreviations and symbols mentioned in this paper are abbreviated as follows:  Schultze, 1922 but differs in its pronotal and elytral scaly markings. Metapocyrtus (Orthocyrtus) melibengoy sp. nov. has two small spots on each side of the disc of its pronotum, and each elytron with one small subbasal spot near the suture, one median stripe from the suture to the lateral side, two subapical spots, a short post-median stripe at stria III, and a long stripe along the lateral margin, confluent with the post-median stripe.
Integument black. Body surface, rostrum, head, and underside moderately shiny. Head finely punctured on dorsum with sparse and very minute pubescence, dorsal surface with a scaly patch of metallic pale-yellow ochre and turquoise round scales near the transverse groove; lateroventral side below the eye with a semi-elliptical scaly patch of metallic pale-yellow-ochre and turquoise round scales interspersed with adpressed metallic bluish piliform scales; forehead between eyes slightly depressed; eyes mediumsized and feebly convex. Rostrum weakly rugose and coarsely punctured on basal 2/3 and finely punctured on apical third, longer than wide (LR/WR:2/1.4mm), dorsum covered with sub-adpressed brownish setae, with large subelongate scaly patch of overlapping light-yellow-ochre, turquoise and bluish round scales on basal half, lateral sur-face with minute subadpressed brownish setae interspersed with long suberect whitish setae, ventral surface with long suberect whitish setae; transverse basal groove distinct; longitudinal groove along midline distinct and forms a shallow concavity; dorsum almost flattish dorsally and apex weakly convex; lateral sides with moderately widened apicad. Antennal scape and funicle almost the same length, scape reaching slightly behind the hind margin of eye, covered with subadpressed fine light-colored setae, and funicle with suberect brownish setae. Funicular segments I and II are almost of the same length, three times longer than wide; segments III-VII nearly as long as wide; club sub-ellipsoidal, nearly 3 times longer than wide. Prothorax subglobular, wider than long (LP/WP:3.1/3.6 mm), finely punctured with minute pubescence, widest at middle, weakly convex on dorsal surface, dorsal contour highest point on basal ¼. Prothorax with the following scaly markings of metallic, light-yellow ochre and turquoise, round scales: a) stripe at the anterior margin, b) two small subcircular spots on each side of discs, c) stripe at the posterior margin, and d) slightly broader stripe before the coxa confluent with the anterior and posterior marginal stripes. Elytra ovate (LE/ WE:6.1/5.7 mm), moderately wider and nearly twice longer than prothorax (WE/ WP: 5.7/3.6 mm, LE/LP: 6.1/3.1 mm), distinctly and randomly punctured with very minute pubescence, dorsum strongly convex, dorsal contour highest before the middle, lateral contour evenly arcuate, widest at middle, apex quite rounded with sparse, white, fine setae. Each elytron with the following scaly markings of pale-yellow-ochre, turquoise and bluish round scales: a) one subbasal spot between stria II and III, b) one median interrupted stripe from suture towards but not reaching lateral margin, c) two subapical spots on dorsolateral surface, d) a short longitudinal post-median stripe at stria III, and e) one long stripe along lateral margin from base to apex, interrupted before middle. Post-median, and lateral marginal stripe confluent at the apex. Legs with moderately clavate femora. Femora black covered with subadpressed bluish piliform scales which tend to get longer towards apex and with yellow-ochre, turquoise and bluish oval scales near apical margin. Tibiae covered with suberect long white setae, weakly serrate along inner edge with few protruding teeth. Fore tibiae and midtibiae bear a mucro at apex. Tarsomeres pubescent. Forecoxae covered with colored piliform scales and with pale-yellow-ochre to bluish round scales; mesocoxae and metacoxae covered with setae. Mesoventrite covered with light-colored setae and with light-yellow and turquoise rounds scales on distal ends. Metaventrite densely covered with white setae and with light-yellow ochre and turquoise elliptical scales on distal ends. Ventrite I slightly depressed on disc, densely covered with white setae and with light-yellow to turquoise elliptical scales towards lateral margin. Ventrite II to V sparsely covered with whitish setae. Ventrite V flattened, apical half finely densely punctured, with minute setae.
Male aedeagus as shown in Habitus as shown in Figs 2 and 4. Females differ from males in the following: a) pronotum slightly wider, and longer than in male; b) base of pronotum slightly widened on sides, c) elytra longer and mod-erately wider, lateral contour widest before the middle; and d) ventrite I slightly convex on disc. Otherwise, the female is similar to the male.
Etymology. The new species is named after its type locality, Mt. Melibengoy, which is the local name of Mt. Parker.
Distribution. Metapocyrtus (Orthocyrtus) melibengoy sp. nov. is known from Tboli Municipality, South Cotabato. Diagnosis. Metapocyrtus (Orthocyrtus) flomlok sp. nov. is closely related to Metapocyrtus (Orthocyrtus) lanusinus Schultze, 1922 but differs in the following: shorter and stouter body, pronotal scaly marks of two huge round spots on each side of disc, distinct and continuous thick longitudinal stripes from the base to the apex of the elytra, and the stouter and shorter aedeagal body. Meanwhile, M. (O.) lanusinus has a thin transverse band at mid-length, and elytral marks having four interrupted longitudinal stripes distinctly short and oftentimes with short spots in between each longitudinal stripe in the mid-length.
Integument black. Body surface, rostrum, head, and underside with weak luster. Head finely punctured on dorsum with sparse and very minute setae, frons covered with metallic golden orange, round scales, lateroventral parts below the eye with a semi-elliptical scaly patch of pale-yellow and turquoise round scales, latero-ventral parts with adpressed metallic bluish piliform scales, forehead between eyes nearly flattish. Eyes medium-sized and feebly convex. Rostrum coarsely rugose on basal 2/3 and finely punctured on apical third, slightly longer than wide (LR/WR:2.1/1.8 mm), dorsum with sparse and adpressed brownish setae, lateral surface with sparse minute subadpressed bluish piliform scales interspersed with brownish and whitish, long suberect setae especially towards the apical margin, ventral surface with long suberect whitish setae; transverse basal groove distinct; longitudinal groove along midline distinct and forms a shallow concavity filled with metallic golden orange with a tinge of green, round scales; dorsum almost flattish dorsally and apex weakly convex; lateral sides with strongly expanded apicad. Antennal scape and funicle of almost the same length, scape reaching the hind margin of eye, covered with subadpressed metallic fine light-colored hairs, and funicle with suberect brownish hairs. Funicular segments I and II almost of the same length, three times longer than wide; segments III-VII nearly as long as wide; club sub-ellipsoidal, nearly 3 times longer than wide. Prothorax subglobular, wider than long (LP/WP:3.8/4.4 mm), finely punctured especially near anterior margin, widest before middle, weakly convex on dorsal surface, dorsal contour highest point before the middle. Prothorax with the following scaly markings of metallic, light-yellow and turquoise round scales: a) thin stripe at the anterior margin, b) two large subcircular spots on each side of disc, c) thin stripe at the posterior margin, and d) slightly broader stripe before the coxa confluent with the anterior and posterior marginal bands. Elytra ovate (LE/ WE:7.0/6.0 mm), slightly wider and moderately longer than prothorax (WE/WP: 6.0/4.4 mm, LE/LP: 7.0/3.8 mm), finely and distinctly punctured with very minute pubescence, strongly convex, dorsal contour highest before the middle, lateral contour evenly arcuate, widest at middle, apex rounded with sparse, colored, fine setae. Each elytron with the following scaly markings of pale-yellow-ochre, turquoise and bluish round scales: a) three continuous longitudinal scaly stripes from basal margin towards apex of the elytron, b) one long stripe along lateral margin from base to apex, c) one premedian longitudinal stripe along suture, and d) very minute and at times negligible spots in the midle of each scaly stripe at the median portion. Legs with moderately clavate femora. Femora black covered with subadpressed light blue and turquoise piliform scales and turquoise elliptical scales near the apical margin. Tibiae covered with suberect long white setae, weakly serrate along inner edge with few protruding teeth. Fore and midtibiae bear a mucro at apex. Tarsomeres pubescent. Forecoxae covered with colored piliform scales and with turquoise elliptical scales; mesocoxae and metacoxae covered with setae. Mesoventrite covered with lightcolored setae and with turquoise rounds scales on distal ends. Metaventrite sparsely covered with light-colored piliform scales and with turquoise round scales on distal ends. Ventrite I slightly depressed on disc, covered with light-colored piliform scales and with light-yellow to turquoise round scales towards lateral margin. Ventrite II to V sparsely covered with whitish setae and piliform scales which tends to get denser at distal ends. Ventrite V flattened, apical half finely coarsely rugose, with minute setae. Male aedeagus as shown in Figs 12-14.
Habitus as shown in Figs 6 and 8. Females differ from males in the following: a) base of pronotum slightly widened on sides, b) elytra longer and moderately wider, lateral contour widest before the middle, c) the three stripes from base to apex in the elytra are interrupted before the middle, and d) ventrite I slightly convex on disc. Otherwise female similar to the male.
Etymology. The new species is named after "flomlok" the old B'laan name of its type locality Polomolok. The term flomlok means hunting ground due to the abundance of wildlife in the area prior to the settlement of lowlanders and agricultural companies.

Remarks. Cabras and Medina (2019) placed the species under the subgenus
Artapocyrtus. However, based on additional materials and further evidence, the authors obviously made some errors, and the species should be placed in the subgenus Orthocyrtus based on the characters mentioned by Cabras et al. (2018). In addition, Cabras and Medina (2019) described the species based on two specimens from Mt. Apo and declared it a new species due to the uniqueness of its elytral and pronotal markings consisting of circular patterns. The shape of the aedeagus of the newly acquired materials (Figs 15-17) further confirms membership of the species in Orthocyrtus and its relationship to the Orthocyrtus lanusinus species group. One of the defining characteristics of Orthocyrtus is the shape of its rostrum. Oriental at an elevation of 400 m. Based on the images of the male and female habitus described in the original paper (Patano et al. 2021: 285, fig. 3) with a size ranging from 13.2-14.5 mm and a holotype of 14.5 mm, it doubtlessly belongs to Orthocyrtus based on its size, shape of the rostrum, as well as the general shape of the male and female habitus. In 2021, specimens that appeared to belong to Metapocyrtus (Artapocyrtus) villalobosae from San Isidro, Davao Oriental, which is part of the range of Mt. Hamiguitan, were donated to UMCRC. Upon examination, the said specimens were found to be very similar to the male holotype, and female paratype in the paper of Patano et al. (2021). The only difference is the short longitudinal subbasal stripes which we believe are simply part of the variability of the species. We believe it was wrongly placed in the subgenus Artapocyrtus and thus, we are proposing that it be transferred to the subgenus Orthocyrtus based on the characters mentioned by Cabras et al. (2018) including the shape of its rostrum (Fig. 21). Furthermore, while the species elytral patterns may have a superficial resemblance to M. (Sclerocyrtus) chamissoi Schultze, 1925, it is actually more closely related to M. (Orthocyrtus) davaoensis Cabras, Medina & Bollino, 2021 described from Davao City and Bukidnon. The general habitus of the male and female, the elytral and pronotal patterns as well as the genitalia are also very similar. Molecular data and/or eversion of the endophallus in the near future can be used in delineating the davaoensis species group which seems to have a widespread form and distribution throughout Mindanao. Eversion of the endophallus in the tribe Pachyrhynchini is quite challenging to accomplish and needs alot of specimens as mentioned by Bollino and Sandel (2017) and Cabras et al. (2018). Notes on the habitat of Metapocyrtus (Orthocyrtus) melibengoy sp. nov. and Metapocyrtus (Orthocyrtus) flomlok sp. nov.
Metapocyrtus (Orthocyrtus) melibengoy sp. nov. was collected from forest vegetation along the Salacafe trail leading to Lake Holon, at an elevation of 1200 m (Fig. 22). Lake Holon is a caldera of Mt. Parker, a potentially active stratovolcano in southern Mindanao. The specimens were collected on leaves of a  (Fig. 23). It was found on the leaves of buyo-buyo (Piper aduncum) and avocado (Persea americana). During personal correspondence with Stan Cabigas, he mentioned and showed photos of the same species from Mt. Matutum together with its possible model/mimic -Pachyrhynchus gilvomaculatus Yoshitake, 2016. Thus, we believe that the population near the pineapple plantation is the remnant population that survived the degradation of the forested habitats and conversion of land in Polomolok. A similar scenario has been observed with M. (Orthocyrtus) davaoensis described based on a limited number of specimens near the lowland of Carmen, Davao City. In our recent surveys of the higher elevation and more forested part of Carmen, a huge thriving population of M. (O.) davaoensis was found.

Discussion
The genus Metapocyrtus is one of the most taxonomically complex genera of the tribe Pachyrhynchini. The genus is characterized by mimicry with other members of Pachyrhynchini (i.e., Pachyrhynchus Germar, 1824, Trichomacrocyrtus Yoshitake, 2018, Eumacrocyrtus Schultze, 1923 as well as other weevil groups (i.e., Alcidodes Marshall, 1939, Eupyrgops Berg, 1898, Polycatus Heller, 1912, Calidiopsis Heller, 1913, and even with the family Cerambycidae as exemplified by the genus Doliops Waterhouse, 1841. For the genus Metapocyrtus, elytral patterns alone or color variation of the scaly markings should not be used as a basis in delineating species since intersubgeneric mimicry among its members as well as color polymorphism is quite a common occurrence (Schultze 1925;Cabras et al. 2021a). In addition, the shape and general profile of the rostrum, pronotum, and body should be considered in identifying species and not only the elytral patterns. Two almost identical species, in terms of elytral patterns or coloration, could turn out to be two species from different subgenera or even tribes. Such mistakes seem common in the Philippines as evidenced by several online materials as well as specimens housed in some museums, and collections that are erroneously identified.
Another problem with this genus is the subgeneric delineation which remains unresolved and requires a thorough revision. As for the subgenus Orthocyrtus, the large body size, shape of its rostrum, and body make this taxon quite straightforward to identify. Despite recent publications on this subgenus, many species remain unknown and some species may even be cryptic; only eversion of the endophallus or molecular data could help in species delineation. However, because of the unabated loss of forest cover in the Philippines due to illegal logging, conversion of forest lands for commercial or agricultural purposes, as well as mining activities, these species are at a high risk of extinction. Thus, discoveries of new species and research on species biology, ecology, and threats are very important as they may provide the International Union of Conservation of Nature Red List and local stakeholders with evidence to be used for their assessment and conservation initiatives.