Sinoncopodura nana, Yu & Zhang & Deharveng, 2014

Yu, Daoyuan, Zhang, Feng & Deharveng, Louis, 2014, A remarkable new genus of Oncopoduridae (Collembola) from China, Journal of Natural History (J. Nat. Hist.) 48 (33 - 34), pp. 2069-2082 : 2071-2081

publication ID

https://doi.org/ 10.1080/00222933.2014.908968

persistent identifier

https://treatment.plazi.org/id/03F0C638-FFCE-FFCC-FDD8-CF6C63EEFCC2

treatment provided by

Carolina

scientific name

Sinoncopodura nana
status

sp. nov.

Sinoncopodura nana sp. nov.

( Figures 1–7 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 )

Type material

Holotype: male on slide, collected on 22 May 2011, Baishanzu National Nature Reserve , Qingyuan County, Zhejiang Province, Southeast China, by Feng ZHANG and Daoyuan YU (sample C9662) . Paratypes: two males and two females on slides, a specimen on SEM stub, same data as holotype.

Holotype and 2 paratypes on slide deposited in the College of Plant Protection , Nanjing Agricultural University ( NJAU), Nanjing, China. Two paratypes on slide and a paratype on SEM stub deposited in the Muséum National d’ Histoire Naturelle ( MNHN), Paris, France.

Description

Body appearance ( Figure 1A View Figure 1 ). Length 580 μm on average without antennae (N = 6, maximum 625 μm for a female, minimum 540 μm for a male; holotype 548 µm). White, without trace of pigment, covered by hyaline scales.

Eyes and PAO. Eyes absent. PAO well developed, moruliform, consisting of numerous subglobular units that appears perforated under SEM examination ( Figure 1B View Figure 1 ), surrounded by six posterior and two anterior ciliated blunt chaetae ( Figure 2A View Figure 2 ); diameter of PAO subequal to the length of Ant. I.

Antenna. Antenna nearly as long as head, length ratio Ant. I: II: III: IV as 1.0: 1.7: 2.3: 3.3. Ten types of chaetae observed on antennae ( Figure 2B View Figure 2 ) .

Ordinary chaetae of two types: type 1, smooth under optical microscope, ciliated under SEM, with pointed apex ( Figure 1C View Figure 1 ); type 2, smooth and more hyaline than type 1 under optical microscope, serrated under SEM, basally swollen, apex often broken.

S-chaetae (sens) of six types: type 3, sens slender and subcylindrical; type 4, like type 3 but shorter; type 5, small rod-like sens; type 6, oval sens, larger than type 5; type 7, roundish sens; type 8, broad wrinkled sens.

Two special types of chaetae: type 9, bifurcate smooth pointed chaetae; type 10, hooked chaetae, apically swollen, with longitudinal ribs under SEM.

The following description of antennal chaetotaxy is based on optical microscope observation; in this condition, chaetae of type 1 are optically of the same morphology (smooth and pointed) as thinner ones of type 3 due to the extreme small size. Ant. I with one small basal microchaeta on ventral side, and a whorl of two ventrolateral type 4 and type 6, seven dorsal type 2 and four ventral type 1. Ant. II with one ventral type 4 and one dorso-distal type 5 as well as 18 type 1 and type 2. Ant. III with ordinary chaetae (type 1 and type 2), arranged in three irregular whorls of 7, 11, 8 chaetae from proximal to distal; Ant. III organ with one type 1, two type 5 and two type 8 chaetae, chaeta S3 shift between S4 and S5. Ant. IV (only available unilaterally from a single specimen in slide) with about seven whorls of chaetae, mostly of type 1 and type 3; in addition, dorsal side with four type 7 and one type 10 chaetae, lateral side with four type 3, ventral side distally with 4– 5 type 9 ( Figure 2B View Figure 2 ). No scales on antennae .

Mouth parts. Labrum prominent, chaetae formula 4/5, 5, 4, all labral chaetae with unusually strong papillae at base, inner two of four distal labral chaetae strong and trifurcate, apical edge not seen ( Figure 2C View Figure 2 ). Mandibular head with pars molaris broad, suddenly narrowed at base of pars incisiva and separated from it by a suture-like ridge or bending; left mandible with five teeth, right one with six teeth ( Figure 3A View Figure 3 ). Maxillary head similar to those described for Oncopodura ( Fjellberg 2007; Jordana et al. 2012), lamella 1, 2 and 4 distinct, other lamellae not seen clearly ( Figure 3B View Figure 3 ). Maxillary outer lobe with one bifurcate palp, one basal chaeta and four sublobal hairs ( Figure 3C View Figure 3 ). Labial palp with three proximal chaetae of same size, papillae of the palp not clearly seen; mentum with five chaetae, the two antero-lateral ones larger than others; submentum with four chaetae, the postero-lateral one smaller; all labial chaetae smooth and pointed ( Figure 3D View Figure 3 ).

Cephalic chaetotaxy. Clypeus with 2, 3, 3 smooth pointed chaetae and 2 + 2 ciliated feathered chaetae ( Figure 2C View Figure 2 ). Dorsally, head with numerous scales and microchaetae ( Figure 3E View Figure 3 ). Laterally, chaetae arranged in four groups according to their shapes and positions. Group1 with four thin smooth pointed chaetae, of decreasing lengths from anterior one to posterior one; group 2 with two subequal ciliated blunt chaetae thinner and longer than those around PAO; group 3 with five subequal smooth pointed chaetae stronger than those of group 1; group 4 with four small spiny subequal chaetae. Group 1, 3 and 4 arranged in a longitudinal line from near PAO to postero-lateral margin of head, group 2 dorso-interior to group 1 and 3 ( Figure 2A View Figure 2 ). Ventrally, head unscaled; two strong chaetae present along linea ventralis, the posterior one smaller, four thinner chaetae present along the posterior margin of labium; all ventral chaetae of head smooth and pointed ( Figure 3D View Figure 3 ).

Legs ( Figure 4A–C View Figure 4 ). Subcoxae with several smooth and strong ciliated chaetae. Coxae I, II and III with at least 2, 2, 2 smooth antero-internal chaetae (exact number uncertain). Trochanter I, II and III with 5, 5, 4 smooth chaetae on each leg, with 3, 2, 1 of them quite thin, and one scale on hind trochanter. Femur I, II and III with 13 chaetae of different size on each leg, including one distal microchaeta extremely small on postero-internal face of hind femur; the large ones serrated under optical microscope; in addition 0, 3, 5 scales present on femora I, II and III. Tibiotarsus I, II and III with 21, 21 and 22 chaetae arranged in seven longitudinal rows and three transversal whorls; clavate thickened chaeta of Tibiotarsus II absent; tenent hair smooth and pointed, slightly thinner than other tibiotarsal chaetae, often broken. Unguis and unguiculus simple without any tooth, unguiculus about 0.75 times as long as the inner side of unguis, pretarsus with a pair of short microchaetae. Ordinary chaetae on legs are smooth under optical microscope and serrated under SEM. Scales on legs are broad, with longitudinal ribs, each rib consisting of numerous rectangular lamellae. Distal edge of these scales usually bilobed ( Figures 4B View Figure 4 , 7A View Figure 7 ).

Abdominal appendages. Ventral tube without chaetae or scales on the trunk, lateral flap with two lateral and one posterior smooth chaetae ( Figure 4D View Figure 4 ).

Tenaculum with 4 + 4 teeth, without chaetae or scales ( Figure 4E View Figure 4 ). Ratio manubrium: dens: mucro as 2.4–2.9: 2.0–2.6: 1.0. Manubrium dorsally with four types of chaetae: 11 + 11 (or 12 + 12) feathered chaetae and 7 + 7 or 6 + 6 smooth pointed chaetae symmetrically distributed, 1 + 1 thin ciliated chaetae at base and 1 + 1 large ciliated chaetae at distal end of midline ( Figure 5A View Figure 5 ); ventral side of manubrium with only scales arranged in five groups (3, 3, 6, 6, 8 scales on median part from proximal to distal group); each lateral side of manubrium with a row of five scales ( Figure 5B View Figure 5 ). Dens without scales, spines or crooks, basal tubercle with two dorsal chaetae, the proximal one stronger; the remaining part of dens with 26 chaetae, seven pairs of them arranged in two longitudinal rows on ventral side ( Figure 5A, B View Figure 5 ); all dental chaetae smooth and pointed under optical microscope, with one longitudinal groove visible under SEM ( Figure 7B View Figure 7 ). Mucro elongate, with six dorsal teeth, the most proximal one at the middle of mucro, similar to the subapical one, three intermediate ones smaller; one dorsal lamella running from proximal tooth to the base of mucro; mucro with one smooth baso-external chaeta as long as distal dental chaetae ( Figure 5A, C View Figure 5 ).

Body chaetotaxy ( Figures 5D, E View Figure 5 , 6 View Figure 6 , 7D–F View Figure 7 ). Ten types of chaetae on tergites.

Ordinary chaetae of eight types: type a, microchaetae, most tergal chaetae of this type; type b, smooth pointed chaetae, their sizes from mesochaetae to macrochaetae; type c, smooth cylindrical macrochaetae, with longitudinal ribs under SEM ( Figure 7C View Figure 7 ); type d, ciliated macrochaetae; type e, feathered or fanlike ciliated macrochaetae; type f, spiny chaetae, smooth and pointed; type g, roundish chaetae as small scales; type h, heavily ciliated macrochaeta stronger than type d.

S-chaetae of one type: type i, normal s-chaetae, longer and thicker than type a microchaetae, its texture similar to type c under SEM ( Figure 7D View Figure 7 ).

Scales of one type: type j, body scales, similar to scales on legs, but lamellae of ribs shortened to triangle or dot ( Figure 7E, F View Figure 7 ).

Th. II: anterior margin with one row of about 12 chaetae, most of them as type f except at least one lateral type h, their exact number not known due to shedding; one type i present anteriorly and at least three type c present laterally; other chaetae all as type a. Th. III with two lateral type c and 12 type a. Abd. I with one type c and eight type a arranged in one row. Abd. II pattern similar to that of Abd. I, with one row of 10 chaetae, only one of them as type c. Abd. III with one posterior type i, three postero-lateral type d, two type c and 12 type a. Abd. IV with four type c, one lateral type d and 11 type a. Abd. V: chaetae in two rows, anterior row with two type a and three type g, posterior row with three type a and two type c, one additional type c present between two rows. Abd. VI: dorsal flap: four macrochaetae on each side and one in middle line, their type unclear due to shedding, 1 + 1 type a present posteriorly; lateral flap with type b as well as several type e ( Figure 5D View Figure 5 ). Bothriotricha not observed, but type c macrochaetae present near the expected location of bothriotricha (arrowed in Figures 5A, B View Figure 5 , 6A View Figure 6 ) .

Female genital plate with 2 + 2 type a genital chaetae and 3 + 3 anterior type e antegenital chaetae ( Figure 5E View Figure 5 ), male genital plate with numerous chaetae.

Pseudopores not observed, probably due to the small size of the species.

Ecology

In soil.

Etymology

Named after its tiny body size.

Redefinition of Oncopoduridae

The discovery of Sinoncopodura gen. nov. and its placement among Oncopoduridae leads to a redefinition of the family. The presence of dental spines as a diagnostic character of Oncopoduridae has to be abandoned, and the following diagnosis can be proposed.

Habitus stocky with Abd. IV subequal or longer than Abd. III along dorsal mid line; body clothed by hyaline scales with discontinuous ribs; antennae usually short, but up to two times as long as head in some cave species; eyes absent ( Oncopodura and Sinoncopodura gen. nov.) or 4 + 4 ( Harlomillsia ); PAO usually present; head dorsally without bothriotricha; trochanteral organ absent; dens subdivided in two parts, with spines and crooks or with only ordinary chaetae; mucro longer than 1/3 of dens, with a few scales or chaetae, without basal tooth.

Key to the genera of Oncopoduridae

1. Eyes present. Mucro with ciliated chaetae .................................. Harlomillsia Eyes absent. Mucro without ciliated chaetae.. ............................................ 2

2. Dens with chaetae differentiated as spines or crooks. PAO, when present, not moruliform. A strongly clavate chaeta is usually present on the mid tibiotarsus.. ................................................................................. Oncopodura Dens with only normal smooth pointed chaetae. PAO moruliform. No strongly clavate chaeta on the mid tibiotarsus.. ..... Sinoncopodura gen. nov.

YU

Department of Earth and Environmental Sciences, Yarmouk University

MNHN

Museum National d'Histoire Naturelle

V

Royal British Columbia Museum - Herbarium

VI

Mykotektet, National Veterinary Institute

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