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ISSN : 1226-9999(Print)
ISSN : 2287-7851(Online)
Korean J. Environ. Biol. Vol.34 No.1 pp.37-40
DOI : https://doi.org/10.11626/KJEB.2016.34.1.037

A New Species of the Cave-dwelling Springtail Lethemurus (Collembola: Tomoceridae) from Korea

Gyu Dong Chang1, Young Gun Choi2, Yeon Jae Bae
1,3*
1Department of Life Science, Graduate School, Korea University, Seoul 02841, Korea
2Institute for Conservation of Wild Species, Daejeon 34093, Korea
3Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Korea
Corresponding author: Yeon Jae Bae, 02-3290-3408, 02-3290-3623, yjbae@korea.ac.kr
March 10, 2016 March 20, 2016 March 20, 2016

Abstract

A new species of the cave-dwelling springtail Lethemurus coreanus Chang and Bae, sp. n. is described from Korea. Lethemurus coreanus can be distinguished from congeners by the spinelike setae on the tibiotarsus, numbers of dental spines, number of setae on the trochanteral organ, and body macrochaetae chaetotaxy. A key to the species of Lethemurus is provided.


초록


    INTRODUCTION

    The springtail family Tomoceridae (Collembola) contains 166 species in 16 genera over the world (Janssens 2010). The rare tomocerid genus Lethemurus was described by Yosii (1970) based on the type species Lethemurus finitimusYosii, 1970 from Japan. Yosii (1970) also recombined Tomocerus (Tritomurus) missusMills, 1940 with Lethemurus missus (Mills) that had been described from the USA. Presently, two species in this genus are known in the world.

    In this study, we describe a new species of Lethemurus from Korea. Comparison of diagnostic characters between congeneric species is provided with a key to the species.

    MATERIALS AND METHODS

    Specimens were collected using aspirator and brush and preserved in 80-100% ethanol in 10-20 mL glass vials. Dissection, slide preparation, and observation were conducted using same methods as described in Chang et al. (2015).

    Materials of the new species are deposited in the Korean Institute of Biospeleology (KIB) in Daejeon, Korea. The following materials of the congeneric species were also examined: Lethemurus missus (Mills): 1 female, Paulter Cave, Monroe CO, Illinois, USA, SJ Taylor & FN Soto-Adames, 14 ix 2009, Natural History Survey Collection, University of Illinois (Urbana-Champaign).

    TAXONOMIC ACCOUNTS

    Genus LethemurusYosii, 1970

    LethemurusYosii, 1970 (Type species: Lethemurus finitimus

    Yosii, 1970; Type locality: Nakatonbetsu Cave, Hokkaido, Japan.

    Diagonosis. Eyes absent. Trochanteral organ well developed with ca 40 setae. Base of dentes without large lateral macrochaetae.

    Distribution. Korea, Japan, USA.

    Lethemurus coreanus Chang and Bae, sp. n.

    (Fig. 1-3)

    (Korean name: Han-guk-gul-ga-si-tok-to-gi)

    Material examined. Holotype: ♂, Gangwon-do, Samcheok- si, Singi-myeon, Daei-ri, Hwanseon-gul Cave (cave NO. 31), 8 i 1974, J Namgung, YG Choi [KIB]. Paratypes: 2♂ (same data as holotype).

    Description (Holotype). Body light brown; some parts darker (Fig. 1A). Body size 5.0 mm; antennae longer than body size up to 4.8 mm, 4 times longer than head length (Fig. 2A). Body segment ratio 17 : 9 in thorax, 34 : 38 : 80 : 53 : 28 : 17 in abdomen. Antennae segment ratio 23 : 49 : 308 : 25. Third antennal organ not differentiated. Eyes and PAO absent (Fig. 1B). Head macrochaetae 2+2 / 5+5 / 2+2 (Fig. 2B). Labrum with smooth setae 6 / 5, 5, 4 and 4 spinules on distal margin (Fig. 3A). Chaetae of mesothoracic collar long. Distribution of body macrochaetae as in Fig. 2C. Leg segment ratio (coxa: trochanter: femur: tibiotarsus) 36 : 29 : 66 : 107. Trochanteral organ with 40 setae in trochanter, 35 setae in femur (Fig. 3B). Mid-legs with 1 femoral spine; hind-legs with 2 femoral spines (Fig. 3C). Unguis, unguiculus, and tenent hair ratio 14 : 9 : 8. Unguis with 1 small proximal inner tooth; unguiculus with 3 small teeth from proximal to middle part (Fig. 3D). Tenent hair tapering, acuminate (Fig. 3D). Ventral tube with numerous setae on posterior part (Fig. 3E, F). Retinaculum quadridentate with only 1 seta on corpus (Fig. 3G). Furca ratio 57 : 76 : 11. Dental spines simple form, 8-10 / 2, I, 1, I, 1, I, 1, I without lateral macrochaetae (Fig. 3H). Mucro long and slender, with 3 evenly spaced teeth; basal tooth with a clear membrane (Fig. 3I).

    Diagnosis(Table 1). Antennae 4 times longer than head length, almost as long as body length (Fig. 2A). Eyes absent (Fig. 2B). Manubrium without marcochaetae in lateral side (Fig. 3A). Trochanteral organ present with ca 40 setae (Fig. 3B). Unguis with 1 tooth and unguiculus with 3 teeth (Fig. 3D). Dentes with several spines (Fig. 3H).

    Etymology. The species epithet “coreanus” is from the country name Korea where the species is described.

    Remarks. Type specimens of this species were collected from “Manmulsang” area in Hwanseon-gul Cave, located 200-250 m from entrance, a dark zone with constant temperature.

    Key to the species of Lethemurus

    1. Trochanteral organ with ca. 40 setae in trochanter and femur (Fig. 3B) ···················· Lethemurus coreanus, sp. n. Trochanteral organ with <40 setae in trochanter and femur ·············································································· 2

    2. 8 / 5, 5, 4 labrum seta and 4 marginal spinules (Fig. 4A in Yosii 1970) ····································· Lethemurus finitimus 6 / 5, 5, 4 labrum seta and 4 marginal spinules ················· ···························································· Lethemurus missus

    Remarks. Key characters of L. missus were examined from the female specimen in Materials and Methods.

    ACKNOWLEDGeMENT

    We sincerely thank Dr. Felipe Soto-Adames (Natural History Survey, University of Illinois at Urbana-Champaign) for his kind invitation and comments about Lethemurus systematics when GDC visited University of Illinois at Urbana- Champaign in 2013. This work was supported by a grant from the National Institute of Biological Resources (NIBR), funded by the Ministry of Environment (MOE) of the Republic of Korea.

    Figure

    KJEB-34-37_F1a.gif
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    KJEB-34-37_F3a.gif
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    Table

    Comparison of diagnostic characters between three species of Lethemurus

    Reference

    1. Chang GD , Lee BH , Choi YG , Bae YJ (2015) Taxonomic review of the cave-dwelling springtail Tomoceridae (Collembola) in Korea , Entomol. Res. Bull, Vol.31 ; pp.65-76
    2. Janssens F (2010) Checklist of the Collembola , Available from URL: http://www.collembola.org/
    3. Mills HR (1948) New North American Tomocerinae , Ann. Entomol. Soc. Am, Vol.41 ; pp.352-359
    4. Yosii R (1970) On some Collembola of Japan and adjacent country II , Contributions from the Biological Laboratory. Kyoto Univ, Vol.23 ; pp.1-32