Biodiversity Data Journal : Taxonomy & Inventories
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Taxonomy & Inventories
A new species and two newly-recorded species of the genus Micrencaustes (Coleoptera, Erotylidae) from China
expand article infoYuhang Yang‡, Xiaoxiao Zhang‡, Jing Liu‡, Jing Li‡
‡ College of Plant Protection, Hebei Agricultural University, Baoding, China
Corresponding author: Jing Li (lijing1976416514@163.com)
Academic editor: Cheng-Bin Wang
Received: 09 Aug 2024 | Accepted: 29 Oct 2024 | Published: 07 Nov 2024
© 2024 Yuhang Yang, Xiaoxiao Zhang, Jing Liu, Jing Li
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Yang Y, Zhang X, Liu J, Li J (2024) A new species and two newly-recorded species of the genus Micrencaustes (Coleoptera, Erotylidae) from China. Biodiversity Data Journal 12: e134304. https://doi.org/10.3897/BDJ.12.e134304
ZooBank: urn:lsid:zoobank.org:pub:0D724FD0-9180-4E14-A8FE-9ECC1B590ECA
 Open Access

Abstract

Background

The genus Micrencaustes Crotch, 1876 (Coleoptera, Cucujoidea, Erotylidae, Erotylinae, Encaustini) includes 44 known species worldwide, 11 species having been reported to occur in China. In recent years, species of genus Micrencaustes in China are constantly being discovered, mainly distributed in southern China.

New information

A new species, Micrencaustes (Mimencaustes) occulta sp. nov., is described and illustrated. Two species, Micrencaustes (Mimencaustes) divisa Arrow, 1925 and Micrencaustes (Micrencaustes) navicularis Arrow, 1921 are recorded from China for the first time. The morphological characteristics of adults of new species are re-described in detail and illustrated. A key to Chinese species of the genus Micrencaustes is provided. The specimens of new species was collected from Yunnan Province and the specimens of Micrencaustes (Mimencaustes) divisa Arrow, 1925 and Micrencaustes (Micrencaustes) navicularis Arrow, 1921 were collected from Hainan Province and Guangdong Province and deposited in the Museum of Hebei University and Institute of Zoology, Chinese Academy of Sciences.

Keywords

Encaustini, beetle, description, key, taxonomy

Introduction

The genus Micrencaustes Crotch, 1876 (Coleoptera, Cucujoidea, Erotylidae, Erotylinae, Encaustini) was established by Crotch (1876) with Encaustes lunulata (MacLeay, 1825) as the type species. In this genus, 44 species have been reported (Chûjô and Chûjô 1989, Chûjô and Chûjô 1990, Li 2006, Li and Ren 2006, Wegrzynowicz 2007, Li et al. 2017) which are mainly distributed in Palearctic, Oriental, Afrotropical and Australasian realms. So far, 11 species have been reported to occur in China: Taiwan, Hainan, Guangxi and Yunnan (Araki 1941, Chûjô 1968, Chûjô and Chûjô 1989, Chûjô and Chûjô 1990, Osawa and Chûjô 1990, Li 2006, Li and Ren 2006, Wegrzynowicz 2007, Meng et al. 2014). Micrencaustes can be distinguished from other genera by the following characters: body size medium to large, non-parallel at both sides; base of elytra and pronotum subequal in width; lacinia with two teeth at apex, maxillary terminal palpomere extremely transverse; submentum with ridges at both sides; with expressed marginal border on each side, prosternal lines present, postmesocoxal lines and postmetacoxal lines present or absent (Crotch 1876, Li 2006). This genus includes two subgenera, the subgenus Mimencaustes having mesocoxal lines, whereas subgenus Micrencaustes does not. In this article, Micrencaustes (Mimencaustes) occulta sp. nov. and Micrencaustes (Mimencaustes) divisa Arrow, 1925 belong to the subgenus Mimencaustes and Micrencaustes (Micrencaustes) navicularis Arrow, 1921 belongs to the subgenus Micrencaustes.

During our examination of the specimens of Micrencaustes from southern China, a new species and two newly-recorded species for China were discovered. A key to the species of Micrencaustes from China is provided.

Materials and methods

Specimens were softened in warm water for 12 hours. Then, the whole abdomen and genitalia were detached from the body. Male and female genitalia were placed in 5% sodium hydroxide (NaOH) solution for 5 minutes, then cleaned with distilled water. Morphological characters were observed using a Motic SMZ-168 stereomicroscope and a detailed description was provide. Photographs were taken with Olympus E-M5 II camera and processed with Adobe Photoshop 2021. Morphological terminology follows Lawrence (Lawrence et al. 2010, Lawrence et al. 2011).

All specimens of this study were deposited in the Museum of Hebei University (MHBU) and Institute of Zoology, Chinese Academy of Sciences (IZAS).

Taxon treatments

Micrencaustes (Mimencaustes) occulta Yang & Li, sp. nov.

Material   Download as CSV 
Holotype:
  1. country:
    China
    ; stateProvince:
    Yunnan
    ; county:
    Yingjiang
    ; verbatimCoordinates:
    24.691355°N, 97.943483°E
    ; year:
    2012
    ; month:
    8
    ; individualCount:
    1
    ; sex:
    1 male
    ; identifiedBy:
    Yibing Ba
    ; occurrenceID:
    E26B1B82-1138-5DBE-BCC0-4B69A840C898

Diagnosis

Body elongate-oval, convex dorsally, black, moderately lustrous. Each elytron with two orange marks and with seven distinct striae. Clypeofrontal sulcus incomplete. Interocular distance about 0.47 times width of head. Antennae long, almost extending to the posterior edge of pronotum, antennomere 3 long and apex slightly swollen, 1.6 times as long as antennomere 4, antennomere 9 almost equal in length and width; antennomere 10 transverse, 2.1 times as wide as long. Maxillary terminal palpomere transverse, nearly semicircular, 2.8 times as wide as long. Lacinia with two teeth at apex. Pronotum with three indistinct teardrop-shaped orange marks and with a few coarse punctures on each side of base. Postmesocoxal lines absent.

Description

Body length: 13.2 mm; width: 6.2 mm, elongate-oval, convex in lateral view, general colour black, moderately lustrous. Pronotum with three indistinct teardrop-shaped orange marks. Each elytron with two orange marks, the first mark reaching the basal edge and with a wave at posterior edge; the second mark at basal three fourths, transverse and curved, with a wave at anterior edge (Fig. 1). Head (Fig. 2a) coarsely punctured on vertex. Clypeus finely punctured, anterior edge straight. Clypeofrontal sulcus incomplete. Eyes large, coarsely facetted; interocular distance about 0.47 times width of head. Antennae (Fig. 2b) long, almost extending to posterior edge of pronotum, covered with golden setae; antennomere 1 swollen, barrel-shaped; antennomere 2 spherical; antennomere 3 long, slightly swollen at apex, 1.6 times as long as antennomere 4; antennomere 9-11 transverse and compact, forming the antennal club, antennomere 9 expanded apically; antennomere 10 crescent-shaped, 2.0 times as wide as long; antennomere 11 nearly fan-shaped; relative lengths of antennomeres 2-11: 1.5: 3.6: 2.1: 2.2: 2.3: 2.2: 2.2: 2.8: 2.0: 2.2. Maxillary terminal palpomere (Fig. 2c) transverse, strongly expanded, nearly triangular, 2.8 times as wide as long. Labial terminal palpomere (Fig. 2d) dolabriform. Mentum (Fig. 2e) small, nearly pentagonal, with middle area triangularly depressed; submentum (Fig. 2e) nearly trapezoidal, with a few coarse punctures in the middle and two extremely coarse punctures at the base.

Figure 1.  

Micrencaustes (Mimencaustes) occulta sp. nov., Yunnan, China.

Figure 2.  

Morphological characters of Micrencaustes (Mimencaustes) occulta sp. nov. a head; b antenna; c maxillary palpus; d labial palpus; e mentum and submentum; f pronotum; g prosternum; h mesoventrite; i protibia and protarsus; j aedeagus. Scale bars: 1.0 mm (a-b, e-j), 0.5 mm (c-d).

Pronotum (Fig. 2f) 2.2 times as wide as long, nearly trapezoidal, convex dorsally, with extremely sparse punctures. Anterior edge curved opposite the head; lateral edge curved, with expressed border and slightly narrowing apically; basal edge weakly sinuate, with a few coarse punctures on each side of base. Anterior angles blunt and slightly protruded, posterior angles almost rectangular. Scutellar shield sparsely punctured, nearly heart-shaped, 1.6 times as wide as long. Each elytron with seven distinct striae, intervals sparsely punctured.

Prosternum (Fig. 2g) finely and sparsely punctured, covered with fine and short setae, anterior edge narrow, posterior edge emarginated. Prosternal process nearly long bell-shaped, prosternal process distinctly and abruptly expanded apically, apical edge of prosternal process emarginated, only slightly extending beyond anterior edge of mesoventrite. Mesoventrite (Fig. 2h) sparsely punctured, with a triangular depression in middle of posterior edge . Metaventrite finely and sparsely punctured and two elongated transverse depressions at posterior edge. Abdomen sparsely punctured, covered with short setae.

Legs (Fig. 2i) with tibiae gradually widening to apices, tibiae and tarsus covered with golden setae.

Male genitalia (Fig. 2j) with median lobe slightly curved, median strut straight, apex slightly wide, 2.3 times as long as median lobe.

Etymology

The species is named for the three indistinct teardrop-shaped orange marks on the pronotum, the marks seen when strong light shines on the pronotum.

Distribution

Micrencaustes (Mimencaustes) occulta Yang & Li sp. nov. is recorded in Yingjiang County, Yunnan Province, China.

Notes

Micrencaustes (Mimencaustes) occulta sp. nov. is similar to Micrencaustes (Micrencaustes) lunulata (Macleay, 1825) due to the body and colour. We examined type specimens of Micrencaustes (Micrencaustes) lunulata (Macleay, 1825) and laboratory collected specimens, these two species being distinguished by the combination of the following characters: Micrencaustes (Mimencaustes) occulta sp. nov. without postmesocoxal lines, each elytron with seven distinct striae, pronotum with a few coarse punctures on each side of the base, body moderately lustrous; Micrencaustes (Micrencaustes) lunulata (Macleay, 1825) with postmesocoxal lines, each elytron with eight distinct striae, pronotum with evenly fine punctures, body shiny.

Micrencaustes (Mimencaustes) divisa Arrow, 1925

Nomenclature

Micrencaustes (Mimencaustes) divisa Arrow, 1925 - Arrow 1925: 79

Material   Download as CSV 
  1. country:
    China
    ; stateProvince:
    Hainan
    ; county:
    Baisha
    ; locality:
    Yuanmen Town
    ; verbatimCoordinates:
    19.158191°N, 109.486479°E
    ; year:
    2007
    ; month:
    5
    ; individualCount:
    1
    ; sex:
    1 female
    ; recordedBy:
    Yibin Ba and Juntong Lang
    ; occurrenceID:
    73A9E8EC-433E-50B9-9FD7-13AA98C4F963

Distribution

Micrencaustes (Mimencaustes) divisa Arrow, 1925 (Fig. 3) is recorded in Yuanmen Town, Baisha County, Hainan Province, China and is also distributed in Myanmar (Arrow 1925, Chûjô and Chûjô 1989).

Figure 3.  

Micrencaustes (Mimencaustes) divisa Arrow, 1925. Specimen from Hainan, China.

Micrencaustes (Micrencaustes) navicularis Arrow, 1922

Nomenclature

Micrencaustes (Micrencaustes) navicularis Arrow,1922 - Arrow 1922: 297

Material   Download as CSV 
  1. country:
    China
    ; stateProvince:
    Guangdong
    ; county:
    Wengyuan
    ; locality:
    Chebaling National Nature Reserve
    ; verbatimCoordinates:
    24.7025°N, 114.2550°E
    ; year:
    2022
    ; month:
    8
    ; individualCount:
    32
    ; sex:
    14 males, 18 females
    ; recordedBy:
    Ming Bai and Panpan Li
    ; occurrenceID:
    4F310F7A-F939-509A-B7FD-FC2CD45FFE53

Distribution

Micrencaustes (Micrencaustes) navicularis Arrow, 1922 (Fig. 4) is recorded in Chebaling National Nature Reserve in Wengyuan County, Shaoguan City, Guangdong Province, China and is also distributed in Laos and Vietnam (Arrow 1922, Chûjô and Chûjô 1989).

Figure 4.  

Micrencaustes (Micrencaustes) navicularis Arrow, 1922. Specimen from Guangdong, China.

Identification keys

The key to species of the genus Micrencaustes from China
1 Postmesocoxal lines absent 2
– Postmesocoxal lines present 6
2 Pronotum and elytra with orange marks 3
– Only elytra with orange marks 5
3 Pronotum with two marks 4
– Pronotum with three marks M. occulta sp. nov.
4 Each elytron with one mark M. liturata (MacLeay)
– Each elytron with two marks M. divisa Arrow
5 2.4 times interocular distance as eye radius; maxillary terminal palpomere nearly 3.0 times as wide as long M. episcaphoides Heller
– 1.5 times interocular distance as eye radius; maxillary terminal palpomere nearly 4.5 times as wide as long M. michioi Osawa & Chûjô
6 Body without marks M. dehaanii (Castelnau)
– Body with obvious marks 7
7 Elytra without marks 8
– Elytra with marks 9
8 Head without orange marks; prosternal lines exceeding the front edge of coxae M. acridentata Li & Ren
– Head with orange marks; prosternal lines reaching the front edge of coxae M. renshii Meng, Ren & Li
9 Pronotum with marks 10
– Pronotum without marks 11
10 The anterior edge of basal mark of elytra connected with the anterior edge of elytra M. lunulata (Macleay)
– The anterior edge of basal mark of elytra not connected with the anterior edge of elytra M. taiwana Araki
11 Each elytron with a mark M. navicularis Arrow
– Each elytron with two marks 12
12 Abdomen with very large punctures along the outside edge of ventrite V M. decipiens Arrow
– Abdomen without very large punctures along the outside edge of ventrite V 13
13 Basal mark of elytron with two black dots near the anterior edge M. biomaculata Meng, Ren & Li
– Basal mark of elytron without black dots M. wunderlichi Heller

Acknowledgements

We are grateful to Ming Bai and Panpan Li (both IZAS), Yibing Ba and Juntong Lang (both MHBU) for their kind help and collection of the specimens. The authors appreciate the valuable suggestions and all kinds of reviewing work on the manuscript by all reviewers and editors. This research was funded by the National Natural Science Foundation of China (No. 31750002), the Special Project of Technological Innovation for Rural Revitalization (No. 22326507D) and the Supported by Hebei Natural Science Foundation (No. C2023204114).

Author contributions

Yuhang Yang is mainly responsible for the description of morphological characteristics and writing of this article. Xiaoxiao Zhang is responsible for photographs, line drawings, specimen pose and preparation. Jing Liu is responsible for specimen anatomy and writing instruction. Jing Li is responsible for the revision of the article.

References

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