Research Article |
Corresponding author: Yoshitaka Kamimura ( kamimura@fbc.keio.ac.jp ) Academic editor: Pavel Stoev
© 2016 Yoshitaka Kamimura, Masaru Nishikawa, Chow-Yang Lee.
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:
Kamimura Y, Nishikawa M, Lee C-Y (2016) A new earwig of the genus Echinosoma from Penang Island, Peninsular Malaysia, with notes on the taxonomic and nomenclatural problems of the genus Cranopygia (Insecta, Dermaptera, Pygidicranidae) . ZooKeys 636: 51-65. https://doi.org/10.3897/zookeys.636.10592
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The pygidicranid earwigs (Dermaptera) of Penang Island, Peninsular Malaysia were re-examined based on material collected in extensive field surveys in 2012–2013 and 2015. Echinosoma roseiventre Kamimura & Nishikawa, sp. n. is described and illustrated, and Cranopygia pallidipennis (de Haan, 1842) is reported from the island for the first time. The taxonomic and nomenclatural problems of the genus Cranopygiasensu
Cranopygia pallidipennis , Cranopygia similis , Echinosoma roseiventre , south-east Asia
Penang Island (Pulau Pinang) is a 299-km2 island located in the Straits of Malacca, approximately 5 km from the western coast of the mainland of Peninsular Malaysia. Thirty-one species of Dermaptera (earwigs) from this small tropical island are reported, based on an extensive field survey conducted in 2012–2013 (
An extensive field survey of earwigs was conducted on Penang Island from March 2012 to March 2013 (see
An additional field survey was conducted by YK on 9–13 March, 2015, during which time two Cranopygia samples were collected from Bukit Jambul (5.348821N, 100.285692E). The site is a hill with a maximum elevation of approximately 200 m a.s.l that is covered with plantations of rubber, durian, banana, and other fruit trees, and is surrounded by secondary forests. A nymphal sample collected this location was reared to adulthood in the laboratory. For comparison, we examined specimens of Cranopygia species from Manchester Museum (MM) and the Natural History Museum (NHM), UK, and the entomological specimen collections of the School of Biological Sciences, Univerisiti Sains Malaysia, Penang, Malaysia.
Male and female genitalia removed from the examined specimens were mounted in Euparal (Waldeck GmbH & Co. KG, Münster, Germany) between two cover slips, and attached to the pin of the respective specimen. The terminologies of
Echinosoma
sp.:
Echinosoma roseiventre sp. n. is a small species less than 8 mm including the forceps. This species differs from all other similar sized species of Echinosoma with the combination of the following characters: abdomen uniformly reddish brown or rosy without a distinct pattern; ultimate tergite not pubescent, but with small rounded swellings; pygidium broader than long; virga very long, more than five times longer than parameres, tubular and simple.
Holotype (male): length of body (without forceps): 7 mm. Length of forceps: 0.9 mm. Head width: 1.5 mm. Pronotum width: 1.6 mm. Pronotum length: 1.1 mm.
Color: General body color dull smoky black but abdomen, especially caudal part, pygidium, and forceps reddish brown or rosy (Fig.
Holotype (male) of Echinosoma roseiventre sp. n. (a), a male (b–d) and a female (e–f) of Cranopygia pallidipennis from Penang Island, and a male of Cranopygia similis from Java (MM No. 3639) (g–i). (a, b, e, g) habitus; (c, d, h, i) male genitalia; (f) female genitalic region and ovipositor. The red and blue arrowheads indicate the expanded outer angle of the parameres (c) and the distal process of the virgae (c, d, i), respectively. Abbreviations: AP, anal plate; ce, cercus (=forceps); gl8, gonoplac (=coxal lobe) VIII; gl9, gonoplac (=coxal lobe) IX; gp8, gonapophysis VIII; gp9, gonapophysis IX; LC9, laterocoxa IX; LP, lateral plate; TG8–TG10, tergum VIII–X. Scale bars: 3 mm in a, b, e, and g; 1 mm in c, f and h; 200 µm in d and i.
Echinosoma roseiventre sp. n. Holotype (male). 7 Right paramere 8 The tip of right virga 9 The base of right virga (indicated by the gray arrowhead) with the funnel-shaped sclerite (indicated by the solid arrowhead) and the long ellipse sclerite (indicated by the open arrowhead). Scale bars: 200 µm.
Paratype (male). Length of body (without forceps), 6.5 mm; length of forceps, 0.8 mm; head width, 1.2 mm; pronotum width, 1.2 mm; pronotum length, 0.8 mm. Antennae broken, five (right) and eleven (left) segments remaining. Tegmina longer, approx. 1.5 times longer than pronotum. Penultimate sternite not strongly narrows posteriorly, almost rectangular.
Female. Unknown.
Holotype: 1 male (genitalia mounted in Euparal between two coverslips and attached to the pin of the specimen), Bukit Jambul, Penang Island, West Malaysia, 27.XI.2012, Y. Kamimura leg. [
Penang Island, Peninsular Malaysia
The specific epithet refers to the characteristic rosy abdomen of this new species.
Echinosoma roseiventre sp. n. is very close to E. andamanensis Srivastava, 1988, described from India. Currently these two species can only be distinguished by differences in the length of the virgae (shorter than five times the parameres in E. andamanensis), the shape of the pygidium (longer than broad in E. andamanensis), and body coloration (E. andamanensis is generally dull smoky black but the abdomen, pygidium, and forceps are shiny;
In addition to the species listed in the key below, E. rufomarginatum Borelli, 1931, which
1 | Abdomen with distinct pattern consisting of three light longitudinal stripes or series of spots | 2 |
– | Abdomen more or less uniformly colored, without distinct pattern | 4 |
2 | Sides of pronotum rounded. Virga almost straight | E. affine Hincks, 1959 |
– | Sides of pronotum straight, parallel. | 3 |
3 | Virga slightly undulate | E. trilineatum Borelli, 1921 |
– | Virga very long, convoluted | E. sarawacense Borelli, 1959 |
4 | Pygidium characteristic, forming a large rounded lobe, filling the space between forceps, produced into a sharp pointed spine above posteriorly | E. maai Srivastava, 2003 |
– | Pygidium normal, without a sharp pointed spine above posteriorly | 5 |
5 | Ultimate tergite with long pubescence | 6 |
– | Ultimate tergite setose or with very short, sparse, adpressed setae | 8 |
6 | Virga not longer than penis lobe | E. sumatranum (de Haan, 1842) |
– | Virga longer than penis lobe | 7 |
7 | Virga convoluted | E. convolutum Hincks, 1959 |
– | Virga almost straight, not convoluted | E. komodense Bey-Bienko, 1970 |
8 | Virga not longer than penis lobe | 9 |
– | Virga longer than penis lobe | 10 |
9 | Penis lobe with long strong bristles (or toothed pad) beside virga | E. setulosum Hincks, 1959 |
– | Penis lobes without long strong bristles (or toothed pad) | E. parvulum Dohrn, 1863 |
10 | Virgae shorter than five times of parameres in length. Pygidium longer than broad | E. andamanensis Srivastava, 1988 |
– | Virgae longer than five times of parameres in length. Pygidium broader than long | E. roseiventre sp. n. |
Cranopygia pallidipennis (de Haan, 1842)
Male, preserved in the collection of the laboratory of entomology (Makmal Entomologi), School of Biological Sciences, Universiti Sains Malaysia: Taman Rimba (Teluk Bahang Recreational Park), Penang Island, 9 XII 2009, Tan Chia Chi leg. The specimen has now been transferred to the entomological specimen collections of the School of Biological Sciences, Universiti Sains Malaysia. Two females (one emerged from nymph on 30 III 2015): Bukit Jambul (secondary forest of a rubber plantation), Penang Island, 11 III 2015, Y. Kamimura leg.
Cranopygia similis (Zacher, 1911): Male, preserved in the collection of the Manchester Museum, the University of Manchester, England: “H. LUCHT, K. O. Blawan, 900/1500 Mr., Idjan Plateau [with unreadable handwritten characters: ? 205.39] / 3639 / Cranopygia similis (Zacher) ♂, det W. D. Hinks” [MM No. 3639].
Malaysia (Kuala Lumpur, Bukit Kuru), Myanmar, Indonesia (Java, Sumatra, Borneo).
First record for Penang Island.
Within the family Pygidicranidae, the subfamily Pygidicraninae Verhoeff, 1902 is characterized by a medium to large body size (rarely less than 20 mm), antennae with 25 segments or more in which the 4th and 5th are wider than they are long, depressed femora, and equally developed right and left penis lobes (
Nearly 25 years later,
Subsequently,
In addition to these nomenclatural problems, recent studies have shown that the morphology of earwig virgae, particularly the length, evolves rapidly due to sperm competition, resulting in considerable variation even among very closely related congeners (
Cranopygia Burr, 1908: 384, 389 [type-species: Pygidicrana cumingi Dohrn, 1868 (original designation)];
Pygidicrana (pars) Audinet-Serville, 1831: 30 [type-species: Pygidicrana v-nigrum Audinet-Serville, 1831 (Monobasic)];
Pyge (pars) Burr, 1908: 384, 390 [type-species: Pygidicrana modesta de Bormans, 1894 (original designation)];
Dicrana (pars) Burr, 1908: 384, 387 [type-species: Pygidicrana frontalis Kirby, 1903 (original designation)];
Picrania (pars) Burr, 1908: 390 [type-species: Pygidicrana liturata Stål, 1855 (original designation)];
Kalocrania Zacher, 1910: 105 [type-species: Pygidicrana marmoricrura Audinet-Serville, 1839 (original designation)]. –
Acrania Burr, 1915a: 432, 436 [Type species: Pygidicrana picta Guérin-Méneville, 1838 (original designation)]. –
Epicranopygia Steinmann, 1986: 269 (proposed new name for Acrania Burr, 1915) [type-species: Pygidicrana picta Guérin-Méneville, 1838 (original designation)];
Paracranopygia Steinmann, 1986: 277 [type-species: Forficula pallidipennis de Haan, 1842 (original designation)];
Cranopygia (Paracranopygia) Sakai, 1996: 4 [= siamensis-group,
Mucrocranopygia Steinmann, 1986: 266 [type-species: Pygidicrana horsfieldi Kirby, 1891 (original designation)];
C. angustata (Dohrn, 1862); C. appendiculata Hincks, 1955; C. assamensis Hincks, 1955; C. bakeri (Borelli, 1921); C. beybienkoi Gorochov & Anisyutkin, 1993; C. bhallaie Kapoor, 1966; C. bifurcata Srivastava, 1980; C. brindlei Srivastava, 1988; C. burmensis Hincks, 1955; C. burri Hincks, 1955; C. carinata Hincks, 1959; C. celebensis (de Bormans, 1903); C. chirurga (Gorochov & Anisyutkin, 1993); C. comata Hincks, 1955; C. constricta Hincks, 1955; C. corymbifera Anisyutkin, 1997; C. crockeri Anisyutkin, 2014; C. cumingi (Dohrn, 1862); C. curtula Hincks, 1955; C. daemeli (Dohrn, 1869); C. dravidia (Burr, 1914); C. eximia (Dohrn, 1862); C. fletcheri Bharadwaj & Kapoor, 1967; C. formosa Hincks, 1955; C. gialaiensis Gorochov & Anisyutkin, 1993; C. guttata (Kirby, 1903); C. horsfieldi (Kirby, 1891); C. imperatrix (Burr, 1899); C. jacobsoni (Boeseman, 1954); C. javana Hincks, 1955; C. kallipygos (Dohrn, 1862); C. lueddemanni Srivastava, 1984; C. luzonica Brindle, 1967; C. maculipes Hincks, 1955; C. manipurensis Srivastava, 1975; C. marmoricrura (Audinet-Serville, 1839); C. modesta (de Bormans, 1894); C. nietneri (Dohrn, 1862); C. nova Anisyutkin, 2015; C. okunii (Shiraki, 1928); C. ophthalmica (Dohrn, 1862); C. pallidipennis (de Haan, 1842); C. parva Brindle, 1975; C. philippinica Burr, 1914; C. picta (Guerin-Méneville, 1838); C. pluto Hebard, 1923; C. proxima Hincks, 1959; C. raja (Burr, 1911); C. rostrata Brindle, 1970; C. sarawacensis Hincks, 1959; C. sauteri (Burr, 1912); C. semenoffi (Burr, 1912); C. siamensis (Dohrn, 1862); C. similis (Zacher, 1911); C. spenceri Srivastava, 2003; C. steineri Srivastava, 1993; C. steinmanni Srivastava, 1988; C. tianshanskyi (Gorochov & Anisyutkin, 1993); C. tonkinensis Hincks, 1955; C. tumida Borelli, 1931; C. valida (Dohrn, 1867); C. vanderdoesi Boeseman, 1954; C. variegata Brindle, 1965; C. vicina Hincks, 1959; C. vietnamensis Gorochov & Anisyutkin, 1993; C. vitticollis (Stål, 1855); C. vittipennis Hincks, 1955.
The external morphology, coloration, and genitalia of the male specimen collected at Taman Rimba (Teluk Bahang Recreational Park), Penang Island are very similar to those of C. pallidipennis (de Haan, 1842) described by de
A male specimen of Cranopygia was recorded from “Penang” in the early 20th century (
Cranopygia pallidipennis seems to be very close to C. similis and can be distinguished from the latter by a larger body size; the pattern of fuscous markings on the head, pronotum, and femora (Fig.
This study was conducted with the approval of the Economic Planning Unit, Malaysia (Reference No. UPE: 40/200/19/2844). We thank D.V. Logunov, G. Beccaloni, S. Khatijah, and C.L. Liew for helping us with specimen examination, and L.N. Anisyutkin and P. Kočárek for useful comments on a previous version of the manuscript. This study was partly supported by a grant for overseas research from Keio University to Y.K. and a Grant-in-Aid for Scientific Research to Y.K. (Kakenhi, Nos. 22770058 and 15K07133) from the Japan Society for the Promotion of Science.