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Research Article
Smooth post-labial chaetae in Homidia (Collembola, Entomobryidae) and the description of four new species from China with the aid of DNA barcoding
expand article infoRong Zhou‡, Ling Huang‡, Yi-Tong Ma‡
‡ Nantong University, Nantong, China

Corresponding author: Yi-Tong Ma ( mayitong@ntu.edu.cn )

Academic editor: Wanda M. Weiner
© 2024 Rong Zhou, Ling Huang, Yi-Tong Ma.
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: Zhou R, Huang L, Ma Y-T (2024) Smooth post-labial chaetae in Homidia (Collembola, Entomobryidae) and the description of four new species from China with the aid of DNA barcoding. ZooKeys 1213: 41-73. https://doi.org/10.3897/zookeys.1213.123839
ZooBank: urn:lsid:zoobank.org:pub:5ABCB962-61FB-4CBC-906B-99B14014637E
Open Access

Abstract

Four new species of Homidia are described from the Guangxi Zhuang Autonomous Region, China. Homidia longiantenna sp. nov. is characterised by its long antenna and slightly expanded post-labial chaetae; H. guangxiensis sp. nov. by the presence of smooth chaetae on the post-labium and posterior face of the ventral tube; H. huapingensis sp. nov. by the presence of smooth post-labial chaetae and pointed tenent hairs; and H. oligoseta sp. nov. by the pointed tenent hairs and fewer macrochaetae on Abdomen IV. Additions to the original description of Homidia acutus Jing & Ma, 2022 are also provided.

Key words

Chaetotaxy, COI, DNA sequences, Guangxi, springtails, taxonomy

Introduction

To date, 77 species of the genus Homidia have been described worldwide (Bellinger et al. 1996–2024). The main characters in the taxonomy of the genus include colour pattern, body chaetotaxy, chaetae of the labial base, claw structure and dental spines. The post-labial chaetae are rarely mentioned in species descriptions because they are usually not different from the normal ciliate chaetae present in most species, except for a few expanded ones. Prior to this study, smooth post-labial chaetae had not been reported in the genus. Here, we describe four new species of Homidia, among which one species has slightly expanded post-labial chaetae, two have smooth post-labial chaetae and the other one lacks expanded or smooth post-labial chaetae. Additions to the original description of Homidia acutus Jing & Ma, 2022 are also provided.

Material and methods

Taxon sampling and specimen examination

Specimens were collected with an aspirator and stored in 99% alcohol. They were mounted on glass slides in Marc André II solution and were studied with a Leica DM2500 phase contrast microscope. Photographs were taken using a Leica DFC300 FX digital camera mounted on the microscope and enhanced with PHOTOSHOP CS2 (Adobe Inc.). Type specimens are deposited in the School of Life Sciences Nantong University, Jiangsu, China.

The nomenclature of the dorsal macrochaetotaxy of the head and interocular chaetae follows Jordana and Baquero (2005) and Mari-Mutt (1986). Labial chaetae are designated following Gisin (1964). Post-labial chaetae follow Chen and Christiansen (1993). Labral and tergal chaetae of the body follow Szeptycki (1973, 1979).

Molecular analysis

DNA was extracted by using an Ezup Column Animal Genomic DNA Purification Kit (Sangon Biotech, Shanghai, China) following the manufacturer’s standard protocols. Amplification of a 658 bp fragment of the mitochondrial COI gene was carried out using a Prime Thermal Cycler (TECHNE, Bibby Scientific Limited, Stone, Staffordshire, UK), performed in 25 μl volumes using Premix Taq polymerase system (Takara Bio, Otsu, Shiga, Japan). The primers and polymerase chain reaction (PCR) programs followed Greenslade et al. (2011). All PCR products were checked using a 1% agarose gel electrophoresis. Successful products were purified and sequenced on an ABI 3730XL DNA Analyser (Applied Biosystem, Foster City, CA, USA). All procedures were completed by Pucheng (Nanjing, China).

DNA sequences were assembled using SEQUENCHER 4.5 (Gene Codes Corp) and then deposited in GenBank (Table 1). Sequences were aligned using ClustalW implemented in MEGA 5.1 (Tamura et al. 2011) with default settings. Pairwise genetic distances were analysed in MEGA 5.1 employing the Kimura 2-parameter (K2P) model (Kimura 1980).

Table 1.
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Number of individuals, GenBank accession numbers and source of sequences of the species in this study.

Species Number of individuals GenBank accession number Source
Homidia huapingensis sp. nov. C7401 PP379450 This study
C7402 PP379451
C8201 PP379452
C8203 PP379453
C8204 PP379454
C8202 PP379455
C8303 PP379456
Homidia longiantenna sp. nov. C8107 PP379457 This study
C8103 PP379458
C8104 PP379459
C8105 PP379460
C8106 PP379461
Homidia guangxiensis sp. nov. C8302 PP379462 This study
C8304 PP379463
C8305 PP379464
Homidia oligoseta sp. nov. C8306 PP379465 This study
C8307 PP379466
C8308 PP379467
C8309 PP379468
Homidia acutus Jing & Ma, 2022 C44-3-a PP379469 This study
C29-2-a PP379470
C29-1-a PP379471
C2902 PP379472
C4404 PP379473

Abbreviations

Ant. antennal segment(s);

Th. thoracic segment(s);

Abd. abdominal segment(s);

mac macrochaeta(e);

mes mesochaeta(e);

ms specialised microchaeta(e);

sens specialised ordinary chaeta(e).

Results

Class Collembola Lubbock, 1873

Order Entomobryomorpha Börner, 1913

Family Entomobryidae Tömösvary, 1882

Homidia Börner, 1906

Diagnosis

Moderate size, usually 1–2 mm; eyes 8+8; antennae four segmented; mucro bidentate and with a basal spine, subapical tooth much larger than apical one; dentes with spines; scales absent on body; macrochaetae on anterior part of Abd. IV arranged as an irregular “collar”.

Homidia longiantenna sp. nov.

https://zoobank.org/67A3996A-CCA2-42CC-BD48-3C878435D11F
Figs 1, 2−8, 9−11, 12−17, 18, 19, 20–27, Tables 2, 3

Type material

Holotype • ♀ on slide, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, 31-V-2023, 25°37′52″N, 109°54′47″E, 935.4 m asl, sample number 1281. Paratype • ♀ on slide, same data as holotype. All collected by Y-T Ma.

Description

Size. Body length up to 3.02 mm.

Coloration. Ground colour pale yellow; eye patches dark blue; scattered brown pigment present on body, especially tibiotarsus, lateral and posterior parts of Abd. IV, sometimes Ant. III–IV and Abd. II–III also with brown pigment (Fig. 1).

Figure 1. 

Habitus of Homidia longiantenna sp. nov. (lateral view). Scale bar: 500 μm.

Head. Antenna not annulated and 0.98–1.07 times length of body. Ratio of Ant. I–IV as 1.00/1.24–1.50/1.06–1.30/2.06–2.60. Distal part of Ant. IV with many sensory chaetae and normal ciliate chaetae, apical bulb bilobed (Fig. 2). Sensory organ of Ant. III with two rod-like chaetae (Fig. 3). Sensory organ of Ant. II with 3(4) rod-like chaetae (Fig. 4). Eyes 8+8, G and H smaller than others, interocular chaetae as p, r, t mes. Dorsal chaetotaxy of head with four antennal (An), five median (M) and eight sutural (S) mac (Fig. 5). Prelabral and labral chaetae as 4/5, 5, 4, all smooth, a0, a1 longer than a2; labral papillae absent (Fig. 6). Basal chaeta on maxillary outer lobe almost as thick as apical one; sublobal plate with three smooth chaetae-like processes (Fig. 7). Lateral process (l. p.) of labial palp E differentiated, as thick as normal chaeta, with tip almost reaching apex of papilla E (Fig. 8). Labial base with MM1R1ReL1L2, chaeta e smooth and other ciliate, R1 sometimes absent, R 0.60–0.73 length of M; anterior post-labial chaetae slightly expanded (Figs 9–11).

Figures 2–8. 

Homidia longiantenna sp. nov. 2 apex of Ant. IV (dorsal view) 3 distal Ant. III (ventral view) 4 distal Ant. II (ventral view) 5 dorsal head (right side) 6 prelabrum and labrum 7 maxillary palp and outer lobe (right side) 8 labial palp. Scale bars: 20 μm.

Figures 9–11. 

Homidia longiantenna sp. nov. 9 labial and post-labial chaetotaxy (right side) 10, 11 photographs of labial and post-labial chaetotaxy (right side). Scale bars: 20 μm.

Thorax. Tergal ms formula on Th. II–Abd. V as 1, 0/1, 0, 1, 0, 0, sens as 2, 2/1, 2, 2, 23, 3 (Figs 12, 18–20). Th. II with four medio-medial (m1, m2, m2i, m2i2), three medio-sublateral (m4, m4i, m4p), 30–38 posterior mac. Th. III with about 39–41 mac (Fig. 12). Coxal macrochaetal formula as 3/4+1, 3/4+2 (Figs 13–15). Trochanteral organ with 71–76 smooth chaetae (Fig. 16). Tenent hair clavate, 0.95–0.98 length of inner edge of unguis; unguis with three inner teeth, basal pair located at 0.38–0.39 distance from base of inner edge of unguis, unpaired tooth at 0.62–0.64 distance from base; unguiculus lanceolate, outer edge slightly serrate (Fig. 17).

Figures 12–17. 

Homidia longiantenna sp. nov. 12 chaetotaxy of Th. II−III (right side) 13−15 coxal chaetotaxy of fore, middle and hind leg 16 trochanteral organ 17 hind foot complex (lateral view). Scale bars: 50 μm (12); 20 μm (13−17).

Abdomen. Range of Abd. IV length as 9.00–9.30 times as dorsal axial length of Abd. III. Abd. I with 11 (a1a, a1–3, m2i, m2–4, m4i, m4p and a5) mac. Abd. II with six (a2, a3, m3, m3e, m3ea, m3ep) central, one (m5) lateral mac. Abd. III with two (a2, m3) central, four (am6, pm6, m7a, p6) lateral mac (Fig. 18). Abd. IV with two (as, ps) normal sens, 14–20 anterior, 6–7 (A4–6, B4–6, Ae7, A4 sometimes absent) posterior and 24–26 lateral mac (Fig. 19). Abd. V with three sens (Fig. 20). Anterior face of ventral tube not seen entirely, line connecting proximal (Pr) and external-distal (Ed) mac oblique to median furrow (Fig. 21); posterior face with five or eight distal smooth and numerous ciliate chaetae (Fig. 22); lateral flap with 7–8 smooth and 19–30 ciliate chaetae (Fig. 23). Manubrial plate dorsally with 14–15 ciliate mac and 3(2) pseudopores (Fig. 24); ventrally with 33–41 ciliate chaetae on each side (Fig. 25). Dens with 54–78 smooth inner spines (Fig. 26). Mucro bidentate with subapical tooth larger than apical one; tip of basal spine reaching apex of subapical tooth; distal smooth section of dens almost equal to mucro in length (Fig. 27).

Figure 18. 

Chaetotaxy of Abd. I−III of Homidia longiantenna sp. nov. (right side). Scale bar: 50 μm.

Figure 19. 

Chaetotaxy of Abd. IV of Homidia longiantenna sp. nov. (right side). Scale bar: 50 μm.

Figures 20–27. 

Homidia longiantenna sp. nov. 20 chaetotaxy of Abd. V (right side) 21 anterior face of ventral tube apically 22 posterior face of ventral tube apically 23 lateral flap of ventral tube 24 manubrial plaque (dorsal view) 25 ventro-apical part of manubrium 26 proximal section of dens (circles also representing spines) 27 mucro. Scale bars: 20 μm.

Etymology

Named after its characteristic long antennae.

Ecology

Found in the leaf litter.

Remarks

The new species is characterised by the long antennae and the slightly expanded post-labial chaetae, and can be easily distinguished from all known species of Homidia. It is similar to the species H. apigmenta Shi, Pan & Zhang, 2010, H. pseudofascia Pan, Zhang & Li, 2015, and H. wanensis Pan & Ma, 2021 in the expanded post-labial chaetae and colour pattern, but can be separated from them by the long antennae and other characters. It is also similar to H. jordanai Pan, Shi & Zhang, 2011 in the long antennae, but significant differences exist between them, such as the post-labial chaetotaxy and central mac on Abd. III and other characters. The detailed character comparisons are listed in Table 2.

Table 2.
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Main differences among the new species and related species of Homidia.

Characters Homidia longiantenna sp. nov. Homidia apigmenta Homidia jordanai Homidia pseudofascia Homidia wanensis
Length ratio of antenna to body 0.98–1.07 0.50 about 1.00 0.59–0.67 0.60–0.62
An irregular transverse stripe on Abd. IV posteriorly present absent absent present present
Chaetal formula of labial base MM1(R1)ReL1L2 M(M1)ReL1L2, L1 & L2 expanded MReL1L2 MM1ReL1L2 MReL1L2
Anterior post-labial chaetae slightly expanded strong expanded not expanded slightly expanded slightly expanded
Inner teeth on unguis 3 4 4 4 4
Mac on Abd. IV anteriorly 14–20 6–9 6–9 8–11 12–13
Mac on Abd. IV posteriorly 6–7 5 3(4) 7–9 7–9
Dental spines 54–78 18–39 20–40 36–50 83

Homidia guangxiensis sp. nov.

https://zoobank.org/D3D8DC59-3275-448D-8E92-B82F205AF05B
Figs 28–29, 30−36, 37−39, 40−45, 46, 47, 48−51, 52–56, Table 3

Type material

Holotype • ♀ on slide, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, Power Station, 2-VI-2023, 25°37′40″N, 109°54′19″E, 682.0 m asl, sample number 1283. Paratypes • 3♀♀ on slides, same data as holotype • ♀ on slide, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, 31-V-2023, 25°37′52″N, 109°54′47″E, 935.4 m asl, sample number 1281. All collected by Y-T Ma.

Description

Size. Body length up to 2.86 mm.

Coloration. Ground colour pale white to yellow; eye patches dark blue; brown to blue-violet pigment present on whole dorsal body, antennae, legs, ventral tube, and manubrium. Some unpigmented irregular stripes or spots present on dorsal side of body (Figs 28, 29).

Figures 28, 29. 

Habitus of Homidia guangxiensis sp. nov. (lateral view). Scale bars: 500 μm.

Head. Antenna not annulated and 0.60–0.80 times length of body. Ratio of Ant. I–IV as 1.00/1.27–1.70/1.21–1.40/1.67–2.41. Distal part of Ant. IV with many sensory chaetae and normal ciliate chaetae, apical bulb bilobed (Fig. 30). Sensory organ of Ant. III with two rod-like chaetae (Fig. 31). Sensory organ of Ant. II with 3–4 rod-like chaetae (Fig. 32). Eyes 8+8, G and H smaller than others, interocular chaetae as p, r, t mes. Dorsal chaetotaxy of head with four antennal (An), five median (M) and eight sutural (S) mac (Fig. 33). Prelabral and labral chaetae as 4/5, 5, 4, all smooth, a0, a1 longer than a2; labral papillae absent (Fig. 34). Basal chaeta on maxillary outer lobe slightly thicker than as apical one; sublobal plate with three smooth chaetae-like processes (Fig. 35). Lateral process (l. p.) of labial palp E differentiated, as thick as normal chaeta, with tip almost reaching apex of papilla E (Fig. 36). Labial base with MRel1L2, M sometimes smooth, R ciliate and 0.50–0.53 length of M, chaetae e and l1 smooth, L2 rarely smooth; some post-labial chaetae (G1–4, H2–4, sometimes X and an unnamed chaeta) smooth (Figs 37–39).

Figures 30–36. 

Homidia guangxiensis sp. nov. 30 apex of Ant. IV (dorsal view) 31 distal Ant. III (ventral view) 32 distal Ant. II (ventral view) 33 dorsal head (right side) 34 prelabrum and labrum 35 maxillary palp and outer lobe (right side) 36 labial palp. Scale bars: 20 μm.

Figures 37–39. 

Homidia guangxiensis sp. nov. 37 labial and post-labial chaetotaxy (right side) 38, 39 photographs of labial and post-labial chaetotaxy (right side). Scale bars: 20 μm.

Thorax. Tergal ms formula on Th. II–Abd. V as 1, 0/1, 0, 1, 0, 0, sens as 2, 2/1, 2, 2, 18–36, 3 (Figs 40, 46–48). Th. II with four medio-medial (m1, m2, m2i, m2i2), three medio-sublateral (m4, m4i, m4p), 33–39 posterior mac. Th. III with 44–49 mac (Fig. 40). Coxal macrochaetal formula as 3/4+1, 3/4+2 (Figs 41–43). Trochanteral organ with 44–71 smooth chaetae (Fig. 44). Tenent hair clavate, 0.68–0.88 length of inner edge of unguis; unguis with three inner teeth, basal pair located at 0.32–0.40 distance from base of inner edge of unguis, unpaired tooth at 0.59–0.68 distance from base; unguiculus lanceolate, outer edge slightly serrate (Fig. 45).

Figures 40–45. 

Homidia guangxiensis sp. nov. 40 chaetotaxy of Th. II−III (right side) 41−43 coxal chaetotaxy of fore, middle and hind leg 44 trochanteral organ 45 hind foot complex (lateral view). Scale bars: 50 μm (40); 20 μm (41−45).

Abdomen. Range of Abd. IV length as 6.51–8.75 times as dorsal axial length of Abd. III. Abd. I with 11 (rarely 10) (a1–3, m2i, m2–4, m4i, m4p and a5, a1a rarely absent) mac. Abd. II with six (a2, a3, m3, m3e, m3ea, m3ep) central, one (m5) lateral mac. Abd. III with two (a2, m3) central, four (am6, pm6, m7a, p6) lateral mac (Fig. 46). Abd. IV with two (as, ps) normal sens, 8–11 anterior, five (A5–6, B4–6, Ae7) posterior and 20–23 lateral mac (Fig. 47). Abd. V with three sens (Fig. 48). Anterior face of ventral tube with 44–46 ciliate chaetae on each side, line connecting proximal (Pr) and external-distal (Ed) mac oblique to median furrow (Fig. 49); posterior face with 9–18 smooth and numerous ciliate chaetae (Figs 50, 51); lateral flap with 7–12 (19) smooth and 11–19 ciliate chaetae (Fig. 52). Manubrial plate dorsally with 10–14 ciliate mac and three pseudopores (Fig. 53); ventrally with (26) 40–47 ciliate chaetae on each side (Fig. 54). Dens with 24–48 smooth inner spines (Fig. 55). Mucro bidentate with subapical tooth larger than apical one; tip of basal spine reaching apex of subapical tooth; distal smooth section of dens almost equal to mucro in length (Fig. 56).

Figure 46. 

Chaetotaxy of Abd. I−III of Homidia guangxiensis sp. nov. (right side) Scale bar: 50 μm.

Figure 47. 

Chaetotaxy of Abd. IV of Homidia guangxiensis sp. nov. (right side). Scale bar: 50 μm.

Figures 48–51. 

Homidia guangxiensis sp. nov. 48 chaetotaxy of Abd. V (right side) 49 anterior face of ventral tube 50 posterior face of ventral tube apically 51 photomicrograph of posterior face of ventral tube apically. Scale bars: 20 μm.

Figures 52–56. 

Homidia guangxiensis sp. nov. 52 lateral flap of ventral tube 53 manubrial plaque (dorsal view) 54 ventro-apical part of manubrium 55 proximal section of dens (circles also representing spines) 56 mucro. Scale bars: 20 μm.

Etymology

Named after its locality: Guangxi Zhuang Autonomous Region.

Ecology

Found in the leaf litter.

Remarks

The new species can be easily distinguished from other species of the genus by the smooth post-labial chaetae and the number and location of smooth chaetae on the posterior face of the ventral tube. Among the known Homidia species, except those species with expanded post-labial chaetae, the post-labial chaetae are rarely mentioned because most have normal ciliate chaetae. Smooth post-labial chaetae are discovered for the first time in the genus. In addition, the smooth chaetae on the posterior face of the ventral tube are usually located at the most distal part of the ventral tube and their number is usually less than 10 in the genus. However, the number and location of the smooth chaetae on the posterior face of the new species are peculiar. It is similar to the species H. acutus Jing & Ma, 2022, H. pseudozhangi Jing & Ma, 2023 and H. zhangi Pan & Shi, 2012 in the colour pattern, but can be separated from them by the smooth post-labial chaetae, inner teeth on unguis and other characters. The detailed character comparisons are listed in Tables 3, 4.

Table 3.
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Variation in some characters of the species described in the present paper.

Species Specimen number Mac on Abd. I Anterior mac on Abd. IV Posterior mac on Abd. IV Lateral mac on Abd. IV Tip of tenent hair Smooth post-labial mac Smooth mac on posterior face of ventral tube
Homidia longiantenna sp. nov. 1281-3A 11+11 14+15 6+7 25+25 clavate absent ?
1281-3B 11+11 18+20 6+7 24+26 clavate absent 8
Homidia guangxiensis sp. nov. 1281-13 10+11 10+10 5+5 20+22 clavate present 10
1283-8A 11+11 10+? 5+5 ?+? clavate present 9
1283-8B 11+12 9+10 5+5 23+? clavate present 12
1283-9A 11+11 8+10 5+5 23+? clavate preent 17
1283-9B 11+11 9+11 5+5 20+22 clavate present 18
Homidia huapingensis sp. nov. 1274-2B 11+11 10+11 5+5 19+20 point present ?
1274-2C 11+12 10+11 5+6 20+20 point present 9
1279-6B 11+12 11+12 6+6 21+? point present 6
1281-10A 11+11 9+10 5+6 19+20 point present 9
1281-10B 11+11 9+9 5+5 22+22 point present 8
1283-8C 12+? 9+10 5+6 22+23 point present 5
Homidia oligoseta
sp. nov.		 1281-11A 11+11 3+5 4+4 16+17 point ? 7
1281-11B 11+? 3+3 4+5 16+16 point absent 7
1281-11C 10+10 3+4 4+4 16+17 point absent 7
1282-4A 11+11 3+4 4+4 15+? point absent 5
1282-4B 11+11 3+3 4+4 12+? point absent 5
1282-5 11+11 3+3 4+4 13+? point absent 5
1282-6 11+11 3+3 4+4 13+15 point absent 6
1283-1A 11+11 3+3 4+4 13+13 point absent 5
1283-1B 11+11 3+4 4+4 13+? point absent 5
1283-2A 10+11 4+5 4+4 12+14 point absent 5
1283-2B 10+11 3+3 4+4 11+? point absent ?
1283-3 10+11 3+3 4+4 13+14 point absent 5
1283-10A 11+11 4+4 4+4 14+? point absent 5
1283-10B 11+11 4+4 4+5 13+13 point absent 5
Homidia acutus 1229-1A 11+11 6+6 5+5 15+? point present 6
1229-1B 11+? 6+6 5+5 1516 point present 6
1229-2A 11+11 ?+? 5+5 16+? point present 6
1229-2B 11+11 6+6 5+5 16+16 point present ?

*? not clearly seen.
Table 4.
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Main differences among the three new species and related species of Homidia.

Characters Homidia guangxiensis sp. nov. Homidia huapingensis sp. nov. Homidia oligoseta sp. nov. Homidia acutus Homidia pseudozhangi Homidia zhangi
Medial stripe on Th. II–III absent absent absent absent present absent
Smooth post-labial chaetae present present absent present absent absent
Tenent hair clavate pointed pointed pointed clavate clavate
Inner teeth on unguis 3 3 3 3 4 4
Smooth chaetae on posterior face of ventral tube 9–18 5–9 5–7 6 4–5 4
Relative position of ms to sens on Abd. I antero-external antero-external antero-external antero-external antero-external antero-internal
Relative position of middle sens to m3 on Abd. V postero-external postero-external postero-external postero-external antero-external postero-external
Mac on Abd. IV anteriorly 8–11 9–12 3–4(5) 6 7–12 8–10
Mac on Abd. IV posteriorly 5 5–6 4(5) 5 6 3(4)

Homidia huapingensis sp. nov.

https://zoobank.org/164C2C44-EE5F-40AF-B682-D01ACA2BC432
Figs 57–58, 59−65, 66−68, 69−76, 77, 78, 79–86, Tables 3, 4

Type material

Holotype • ♀ on slide, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, 31-V-2023, 25°37′52″N, 109°54′47″E, 935.4 m asl, sample number 1281. Paratypes • 2♀ on slides, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Guangfu Mountain, 26-V-2023, 25°33′44″N, 109°56′16″E, 1341.0 m asl, sample number 1274 • ♀ on slide, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Guangfu Mountain, 29-V-2023, 25°33′25″N, 109°56′38″E, 1340.5 m asl, sample number 1279 • ♀ on slide, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, 31-V-2023, 25°37′52″N, 109°54′47″E, 935.4 m asl, sample number 1281 • 2♀ on slides, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, Power Station, 2-VI-2023, 25°37′40″N, 109°54′19″E, 682.0 m asl, sample number 1283. All collected by Y-T Ma.

Description

Size. Body length up to 2.92 mm.

Coloration. Ground colour pale white to yellow; eye patches dark blue; brown to blue-violet pigment present on whole dorsal body, antennae, legs, ventral tube, and manubrium. Some unpigmented irregular stripes or spots present on dorsal side of body (Figs 57, 58).

Figures 57, 58. 

Habitus of Homidia huapingensis sp. nov. (lateral view). Scale bars: 500 μm.

Head. Antenna not annulated and 0.59–0.64 times length of body. Ratio of Ant. I–IV as 1.00/1.28–1.40/1.11–1.36/2.00–2.25. Distal part of Ant. IV with many sensory chaetae and normal ciliate chaetae, apical bulb bilobed (Fig. 59). Sensory organ of Ant. III with two rod-like chaetae (Fig. 60). Sensory organ of Ant. II with 4–5 rod-like chaetae (Fig. 61). Eyes 8+8, G and H smaller than others, interocular chaetae as p, r, t mes. Dorsal chaetotaxy of head with four antennal (An), five median (M) and eight sutural (S) mac (Fig. 62). Prelabral and labral chaetae as 4/5, 5, 4, all smooth, a0, a1 longer than a2; labral papillae absent (Fig. 63). Basal chaeta on maxillary outer lobe slightly thicker than as apical one; sublobal plate with three smooth chaetae-like processes (Fig. 64). Lateral process (l. p.) of labial palp E differentiated, as thick as normal chaeta, with tip almost reaching apex of papilla E (Fig. 65). Labial base with MRel1L2, M rarely smooth, R ciliate and 0.50–0.69 length of M, chaetae e and l1 smooth, L2 ciliate; some post-labial chaetae (G1–4, H2–4, rarely X, X3 and 1–2 unnamed chaetae) smooth (Figs 66–68).

Figures 59–65. 

Homidia huapingensis sp. nov. 59 apex of Ant. IV (dorsal view) 60 distal Ant. III (ventral view) 61 distal Ant. II (ventral view) 62 dorsal head (right side) 63 prelabrum and labrum 64 maxillary palp and outer lobe (right side) 65 labial palp. Scale bars: 20 μm.

Figures 66–68. 

Homidia huapingensis sp. nov. 66 labial and post-labial chaetotaxy (right side) 67, 68 photographs of labial and post-labial chaetotaxy (right side). Scale bars: 20 μm.

Thorax. Tergal ms formula on Th. II–Abd. V as 1, 0/1, 0, 1, 0, 0, sens as 2, 2/1, 2, 2, 23–37, 3 (Figs 69, 77–79). Th. II with four medio-medial (m1, m2, m2i, m2i2), three medio-sublateral (m4, m4i, m4p), 32–42 posterior mac. Th. III with 45–57 mac (Fig. 69). Coxal macrochaetal formula as 3/4+1, 3/4+2 (Figs 70–72). Trochanteral organ with about 40–70 smooth chaetae (Fig. 73). All tenent hairs pointed and 0.53–0.68 length of inner edge of unguis; unguis with three inner teeth, basal pair located at 0.29–0.35 distance from base of inner edge of unguis, unpaired tooth at 0.59–0.62 distance from base; unguiculus lanceolate, outer edge slightly serrate (Figs 74–76).

Figures 69–76. 

Homidia huapingensis sp. nov. 69 chaetotaxy of Th. II−III (right side) 70−72 coxal chaetotaxy of fore, middle and hind leg 73 trochanteral organ 74−76 foot complex of fore, middle and hind leg (lateral view). Scale bars: 50 μm (69); 20 μm (70−76).

Abdomen. Range of Abd. IV length as 6.43–7.50 times as dorsal axial length of Abd. III. Abd. I with 11 (sometimes 12) (a1a, a1–3, m2i, m2–4, m4i, m4p and a5, an unnamed mac sometimes present) mac. Abd. II with six (a2, a3, m3, m3e, m3ea, m3ep) central, one (m5) lateral mac. Abd. III with two (a2, m3) central, four (am6, pm6, m7a, p6) lateral mac (Fig. 77). Abd. IV with two (as, ps) normal sens, 9–12 anterior, 5–6 (A5–6, B5–6, Ae7, A4 sometimes present) posterior and 19–23 lateral mac (Fig. 78). Abd. V with three sens (Fig. 79). Anterior face of ventral tube with 44–55 ciliate chaetae on each side, line connecting proximal (Pr) and external-distal (Ed) mac oblique to median furrow (Fig. 80); posterior face with 5–9 smooth and numerous ciliate chaetae (Fig. 81); lateral flap with 9–11 smooth and 16–25 ciliate chaetae (Fig. 82). Manubrial plate dorsally with 12–17 ciliate mac and 2–4 pseudopores (Fig. 83); ventrally with 39–60 ciliate chaetae on each side (Fig. 84). Dens with 37–66 smooth inner spines (Fig. 85). Mucro bidentate with subapical tooth larger than apical one; tip of basal spine reaching apex of subapical tooth; distal smooth section of dens almost equal to mucro in length (Fig. 86).

Figure 77. 

Chaetotaxy of Abd. I−III of Homidia huapingensis sp. nov. (right side). Scale bar: 50 μm.

Figure 78. 

Chaetotaxy of Abd. IV of Homidia huapingensis sp. nov. (right side). Scale bar: 50 μm.

Figures 79–86. 

Homidia huapingensis sp. nov. 79 chaetotaxy of Abd. V (right side) 80 anterior face of ventral tube apically 81 posterior face of ventral tube apically 82 lateral flap of ventral tube 83 manubrial plaque (dorsal view) 84 ventro-apical part of manubrium 85 proximal section of dens (circles also representing spines) 86 mucro. Scale bars: 20 μm.

Etymology

Named after its locality: Huaping Natural Reserve, Guangxi Guangxi Zhuang Autonomous Region.

Ecology

Found in the leaf litter.

Remarks

The new species is very similar to H. guangxiensis sp. nov. and H. acutus Jing & Ma, 2022 in the colour pattern, smooth post-labial chaetae, inner teeth on unguis and central chaetae on Abd. IV posteriorly, but can be separated from them by the tenent hair, central chaetae on Abd. IV anteriorly and smooth chaetae on the posterior face of the ventral tube. The detailed character comparisons are listed in Tables 3, 4.

Homidia oligoseta sp. nov.

https://zoobank.org/F75FD2C9-613D-415C-A090-F9BAC8ED6ECB
Figs 87–89, 90−96, 97, 98, 99−106, 107, 108, 109–116, Tables 3, 4

Type material

Holotype • ♀ on slide, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, 31-V-2023, 25°37′52″N, 109°54′47″E, 935.4 m asl, sample number 1281. Paratypes • 2♀ on slides, same data as holotype • 4♀ on slides, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, 1-VI-2023, 25°38′01″N, 109°54′30″E, 707.8 m asl, sample number 1282 • 7♀ on slides, China, Guangxi Zhuang Autonomous Region, Guilin City, Longsheng Autonomous County, Huaping Natural Reserve, Tianping Mountain, Power Station, 2-VI-2023, 25°37′40″N, 109°54′19″E, 682.0 m asl, sample number 1283. All collected by Y-T Ma.

Description

Size. Body length up to 2.21 mm.

Coloration. Ground colour pale white to yellow; eye patches dark blue; brown to blue-violet pigment present on whole dorsal body, antennae, legs, ventral tube, and manubrium; some unpigmented irregular stripes or spots present on dorsal side of body; Th. II often with less brown pigment (Figs 87–89).

Figures 87–89. 

Habitus of Homidia oligoseta sp. nov. (lateral view). Scale bars: 500 μm.

Head. Antenna not annulated and 0.56–0.62 times length of body. Ratio of Ant. I–IV as 1.00/1.25–1.47/1.00–1.43/2.00–2.71. Distal part of Ant. IV with many sensory chaetae and normal ciliate chaetae, apical bulb bilobed (Fig. 90). Sensory organ of Ant. III with two rod-like chaetae (Fig. 91). Sensory organ of Ant. II with 2–3 rod-like chaetae (Fig. 92). Eyes 8+8, G and H smaller than others, interocular chaetae as p, r, t mes. Dorsal chaetotaxy of head with four antennal (An), five median (M) and eight sutural (S) mac (Fig. 93). Prelabral and labral chaetae as 4/5, 5, 4, all smooth, a0, a1 longer than a2; labral papillae absent (Fig. 94). Basal chaeta on maxillary outer lobe slightly thicker than as apical one; sublobal plate with three smooth chaetae-like processes (Fig. 95). Lateral process (l. p.) of labial palp E differentiated, as thick as normal chaeta, with tip reaching or exceeding apex of papilla E (Fig. 96). Labial base with MRel1L2, chaetae e and l1 smooth, other ciliate; R 0.53–0.60 length of M. All post-labial chaetae ciliate (Figs 97, 98).

Figures 90–96. 

Homidia oligoseta sp. nov. 90 apex of Ant. IV (dorsal view) 91 distal Ant. III (ventral view) 92 distal Ant. II (ventral view) 93 dorsal head (right side) 94 prelabrum and labrum 95 maxillary palp and outer lobe (right side) 96 labial palp. Scale bars: 20 μm.

Figures 97, 98. 

Homidia oligoseta sp. nov. 97 labial and post-labial chaetotaxy (right side) 98 photograph of labial and post-labial chaetotaxy (right side). Scale bars: 20 μm.

Thorax. Tergal ms formula on Th. II–Abd. V as 1, 0/1, 0, 1, 0, 0, sens as 2, 2/1, 2, 2, 39–55, 3 (Figs 99, 107–109). Th. II with four medio-medial (m1, m2, m2i, m2i2), three medio-sublateral (m4, m4i, m4p), 32–37 posterior mac. Th. III with 45–50 mac (Fig. 99). Coxal macrochaetal formula as 3(4)/4+1, 3(4)/4+2 (Figs 100–102). Trochanteral organ with 40–57 smooth chaetae (Fig. 103). All tenent hairs pointed and 0.60–0.86 length of inner edge of unguis; unguis with three inner teeth, basal pair located at 0.30–0.36 distance from base of inner edge of unguis, unpaired tooth at 0.58–0.71 distance from base; unguiculus lanceolate, outer edge slightly serrate (Figs 104–106).

Figures 99–106. 

Homidia oligoseta sp. nov. 99 chaetotaxy of Th. II−III (right side) 100, 102 coxal chaetotaxy of fore, middle and hind leg 103 trochanteral organ 104−106 foot complex of fore, middle and hind leg (lateral view). Scale bars: 50 μm (99); 20 μm (100−106).

Abdomen. Range of Abd. IV length as 4.75–6.25 times as dorsal axial length of Abd. III. Abd. I with 11 (10) (a1–3, m2i, m2–4, m4i, m4p and a5, a1a sometimes absent) mac. Abd. II with six (a2, a3, m3, m3e, m3ea, m3ep) central, one (m5) lateral mac. Abd. III with two (a2, m3) central, four (am6, pm6, m7a, p6) lateral mac (Fig. 107). Abd. IV with two (as, ps) normal sens, 3–4(5) anterior, 4(5) (A4–6, B4–5, A5 rarely present) posterior and 11–17 lateral mac (Fig. 108). Abd. V with three sens (Fig. 109). Anterior face of ventral tube with 19–24 ciliate chaetae on each side, line connecting proximal (Pr) and external-distal (Ed) mac oblique to median furrow (Fig. 110); posterior face with 5–7 smooth and numerous ciliate chaetae (Fig. 111); lateral flap with 6–10 smooth and 7–12 ciliate chaetae (Fig. 112). Manubrial plate dorsally with 9–12 ciliate mac and three pseudopores (Fig. 113); ventrally with 22–30 ciliate chaetae on each side (Fig. 114). Dens with 16–31 smooth inner spines (Fig. 115). Mucro bidentate with subapical tooth larger than apical one; tip of basal spine reaching apex of subapical tooth; distal smooth section of dens almost equal to mucro in length (Fig. 116).

Figure 107. 

Chaetotaxy of Abd. I−III of Homidia oligoseta sp. nov. (right side) Scale bar: 50 μm.

Figure 108. 

Chaetotaxy of Abd. IV of Homidia oligoseta sp. nov. (right side) Scale bar: 50 μm.

Figures 109–116. 

Homidia oligoseta sp. nov. 109 chaetotaxy of Abd. V (right side) 110 anterior face of ventral tube 111 posterior face of ventral tube apically 112 lateral flap of ventral tube 113 manubrial plaque (dorsal view) 114 ventro-apical part of manubrium 115 proximal section of dens (circles also representing spines) 116 mucro Scale bars: 20 μm.

Etymology

The name of the new species is derived from the Latin oligo and seta, which means only a few chaetae are present on each side of the anterior part of Abd. IV.

Ecology

Found in the leaf litter.

Remarks

The new species is very similar to H. huapingensis sp. nov. and H. acutus Jing & Ma, 2022 in the colour pattern and pointed tenent hair, but can be separated from them by the chaetotaxy of Abd. IV and smooth post-labial chaetae. The detailed character comparisons are listed in Tables 3, 4.

Homidia acutus Jing & Ma, 2022

Figs 117, 118–120

Material examined

Holotype and three paratypes • China, Jiangxi Province, Pingxiang City, Luxi County, Gate of Wugong Mountain, 7-XI-2020, 27°29′27″N, 114°07′33″E, 393.0 m asl, sample number 1229, collected by Y-T Ma.

Additions to original description

Colour pattern shown in Fig. 117. Ps2 mac present on dorsal head (Fig. 118) (Ps2 is not shown in the original figure because of my carelessness). Post-labial chaetae G1–4 and H2–4 smooth, sometimes an unnamed chaeta also smooth, chaeta H1 slightly ciliate and others normal ciliate (Figs 119, 120).

Figure 117. 

Habitus of Homidia acutus Jing & Ma, 2022 (lateral view). Scale bar: 500 μm.

Figures 118–120. 

Homidia acutus Jing & Ma, 2022 118 dorsal head (right side) 119 labial and post-labial chaetotaxy (right side) 120 photograph of labial and post-labial chaetotaxy (right side). Scale bars: 20 μm.

Molecular results

Sequenced individuals in the present study had a mean K2P distance of COI sequences between 0.177–0.329. The shortest interspecific distance was 0.177 between H. guangxiensis sp. nov. and H. oligoseta sp. nov. and the greatest was 0.329 between H. huapingensis sp. nov. and H. longiantenna sp. nov. (Table 5). Therefore, the interspecific distances of COI between the four new species were more than the accepted barcoding gap recently reported for species of Entomobryidae (Zhang et al. 2018) and Tomoceridae (Yu et al. 2018). The molecular distances coincided with the morphological divergences, thus further supporting the separation of the four distinct species (Fig. 121).

Table 5.
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Genetic distances (mean K2-P divergence) within and between species in this study.

Species Homidia huapingensis sp. nov. Homidia longiantenna sp. nov. Homidia guangxiensis sp. nov. Homidia oligoseta sp. nov. H. acutus
Homidia huapingensis sp. nov. 0.005−0.074
Homidia longiantenna sp. nov. 0.305−0.329 0.000−0.004
Homidia guangxiensis sp. nov. 0.250−0.275 0.225−0.234 0.000−0.005
Homidia oligoseta sp. nov. 0.257−0.288 0.182−0.197 0.177−0.193 0.000−0.061
Homidia acutus 0.235−0.261 0.290−0.300 0.235−0.246 0.242−0.259 0.000−0.053
Figure 121. 

Neighbour joining tree (using K2P model) of five Homidia species based on COI sequences.

Discussion

Like the chaetae on the labial base, the post-labial chaetae are also of various types. Three species (H. acutus Jing & Ma, 2022; H. huapingensis sp. nov. and H. oligoseta sp. nov.) have smooth post-labial chaetae; three species (H. longiantenna sp. nov., H. pseudofascia Pan, Zhang & Li, 2015 and H. wanensis Pan & Ma, 2021) have slightly expanded post-labial chaetae and five species (H. apigmenta Shi, Pan & Zhang, 2010, H. latifolia Chen & Li, 1999, H. polyseta Chen, 1998, H. qimenensis Yi & Chen, 1999 and H. triangulimacula Pan & Shi, 2015) have strongly expanded post-labial chaetae; most species have normal post-labial ciliate chaetae, or the form of the chaetae is not mentioned.

Colour pattern is a very important character in the taxonomy of Collembola, but some different species may share a very similar colour pattern, such as H. acutus, H. guangxiensis sp. nov., H. huangxiensis sp. nov. and H. oligoseta sp. nov. Therefore, it is necessary to combine colour pattern with other characters, such as the tip of the tenent hair, post-labial chaetae and smooth chaetae on the posterior face of the ventral tube, in the taxonomy of Collembola. In addition, COI sequences are useful in separating morphologically similar species.

Additional information

Conflict of interest

The authors have declared that no competing interests exist.

Ethical statement

No ethical statement was reported.

Funding

This research was funded by the National Natural Sciences Foundation of China (32070403).

Author contributions

Rong Zhou: sorting specimens and writing a manuscript. Liang Huang: analysis of molecular results. Yi-Tong Ma: collecting research materials, microscopic observations, preparing figures.

Author ORCIDs

Rong Zhou https://orcid.org/0000-0002-6908-472X

Ling Huang https://orcid.org/0000-0002-6073-9427

Yi-Tong Ma https://orcid.org/0000-0002-8660-0503

Data availability

All of the data that support the findings of this study are available in the main text.

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