Ceratrimeria yasumatsui (Uchida, 1940)

Babenko, A. B., Nakamori, T., Ohira, A. & Potapov, M. B., 2021, The genus Ceratrimeria Bӧrner, 1906 (Collembola: Neanuridae, Pseudachorutinae) in the fauna of Japan, Far Eastern Entomologist 442, pp. 18-32 : 25-29

Ceratrimeria yasumatsui (Uchida, 1940)

Figs 3–10 , 22–32

Pseudachorutes yasumatsui Uchida, 1940: 9 (type locality: Japan, Kyushu , Mt. Hikosan).

MATERIAL EXAMINED. Cotypes (3 ex.): Japan, Hikosan , Fukuoka Prefecture, 28. VII

1939, H. Uchida leg. (One whole and two headless specimens mounted on two slides; all kept in the Aomori Prefectural Museum, APM1618-13–14). Topotypes: Japan, Kyushu

Island, Fukuoka Prefecture, Tagawa, Mt. Hikosan , 864 m alt., 33.4832° N, 130.9333°, E rotten wood, 30.VI 2020, 7 ex., A. Ohira leg. Other material: Japan, Kyushu Island ,

Miyazaki Prefecture, Ohkawauchi, Shiiba Village, Mt. Tsunodake, Yatate, GPS 70: 1174 m

alt., 32.3708° N, 131.0856° E, shadow beech forest, rotten wood, 05.VIII 2016, 1 ex. (No

2016-8); same forest, but debris and soil under rotten wood, 05.VIII 2016, 2 ex. (No 2016-9);

same area, but GPS 71: 1201 m alt., 32.3648° N, 131.0865° E, Cryptomeria plantation, rotten wood, 05. VIII 2016, 3 ex. (No 2016-11); Miyazaki Prefecture, Kashiba, Misato-cho, foot of

Mt. Sanpo-dake , along trail to waterfall, 794 m alt., 32.3541° N, 131.2101° E, evergreen forest ( Quercus ), rotten wood, 06.VIII 2016, 2 ex. (No 2016-15). All T. Nakamori, S. Saitoh ,

M. Potapov & N. Kuznetsova leg.

DNA BARCODE. Three specimens from Mt. Hikosan (the type locality, 33.4832° N,

130.9333° E, 30.VI 2020) were barcoded. DNA sequences of 16s gene were determined, but the CO1 gene was not successfully amplified using PCR. Museum voucher numbers and

INSD accession numbers are given in Table 1. The p-distances between C. yasumatsui and

C. takaoensis were greater than those noted between individuals of the same species for 16S

gene ( Table 2).

REDESCRIPTION. Length (without antennae) of available specimens from Miyazaki

Prefecture 1.5–3.0 mm [about 2 mm after Uchida (1940)], body wide, 0.70–1.28 mm in the widest area (Abd.2–3), length: width = 2.1–2.3. Mounted specimens from Mt. Hikosan even larger: length 3.0– 3.7 mm, width 1.4–2.1 mm. Abd.6 small, but clearly visible from above,

posterior edge of Abd.5 rounded. Colour in alcohol deep blue with numerous small lighter spots, ocular plate bluish-black, Ant .4 yellowish to orange. Eight more or less large colourless patches present dorsally ( Figs 3–5 ): one medial on posterior side of head shared with

Th.1, two smaller ones dorso-laterally at Th.2–3 border (poorly visible in some specimens),

two large patches laterally on Abd.1, and one medial patch covering almost all dorsal side of

Abd.4, one small medial patch on anterior part of Abd.5, and one patch covering entire Abd.6.

All these patches, as well as ventral side of body and appendages ( Fig. 6 ), orange in alive specimens. Hypodermic blue pigment also absent from foveae and intersegmental boundaries on dorsal side of body, but usually present as sparse spots ventrally on head, body from Th.1

to Abd.6 and also on legs. Tegument granulations uniform and not particularly strong.

Antennae clearly longer than head diagonal ( Fig. 7 ), ratio as 1.2–1.6: 1, Ant .3–4 longer than Ant .1–2 taking together, ratio as 1.4–1.7: 1. Ant .3–4 fused dorsally, ventral separation well marked. Ant .4 with a trilobed apical vesicle, external ms, subapical organite, seta i and several broaden curved sensilla present dorsally ( Figs 23–24 ), S 9 sometimes absent, number of sensilla in S 2 position and in proximal part of Ant .4 variable, total number of ordinary setae on Ant .4 clearly higher than usual. Whole ventral side of Ant .4 covered by numerous short sensilliform setae ( Fig. 25 ). Inner sensilla of AO together with dorsal guard (sgd)

moved to upper half of Ant .4, inner sensilla located at right angle to each other and covered by cuticular fold ( Fig. 26 ); ventral guard (sgv) with ms in usual position in proximal part of

Ant .3–4 ( Fig. 25 ). Ant .1–2 with 11–12 and 14–15 (whole range 14–19) setae, respectively,

setae on dorsal side being much shorter than ventral or lateral ones.

Figs 13–22. Ceratrimeria takaoensis (13–21) and C. yasumatsui (22): 13 – mandible; 14 –

maxilla; 15 – Ant .3–4, dorsal view; 16 – the same, ventral view; 17 – PAO and nearest ocelli;

18 – labium; 19 – labrum; 20 – medial part of Abds.5; 21 – furca; 22 – ventral chaetotaxy of abdomen. Scales: Figs 22 – 1 mm, 15–16, 18–21 – 0.1 mm, 13–14, 17 – 0.01 mm.

Head with 8+8 subequal ocelli. PAO narrowly elliptical consisting of 20–25 densely packed vesicles, located in deep rim ( Fig. 27 ). Buccal cone elongate. Maxilla styliform, usually with two tiny apical teeth ( Fig. 31 ), number of lamellae uncertain. Mandible delicate, with several teeth ( Fig. 30 ), number of subapical teeth apparently unstable. Distal edge of labrum rounded with four tiny papillae, number of labral setae usually as follows: 4/2-3-3-4 ( Fig. 29 ) with few observed abnormalities. Main part of labium with four proximal ordinary setae and a distal seta L on a tiny papilla, labial organites invisible; submentum also with a usual set of four setae (E, F, G, and f in an unusual position), but mentum with 1–2 additional setae (5–6,

totally) ( Fig. 28 ). Perilabial area with 5 setae on each side, medial ones longer. Head with

2+2 long setae along ventral line.

Dorsal chaetotaxy as in Figs 8–10 : only long, whip-like sensilla on each tergum clearly visible, 10–12 times longer than ordinary microsetae; number of sensilla per half tergum as follows: 22/21111. Th.2 with a lateral ms present. Microsetae poorly visible but very numerous,

forming two irregular lines on most terga excluding Th.1 ( Figs 8–10 ). Dorsal side of head also with numerous tiny setae, only two setae located laterally to ocellus B and PAO longer.

Thoracic sterna without setae. VT in all available specimens with 3+3 setae. Ventral abdominal setae distinctly longer than dorsal ones, clearly differentiated and also numerous

(Fig. 22). Main characteristics: Abds.1 usually with 1+1 setae, Abds.2 with 2+2 setae, number of setae on Abds.3–4 high and unstable. Each anal valve with two setae hr. Tenaculum with

3+3 teeth. Furca long, reaching mid part of VT. Manubrium with 8+8 setae on main part, 8–9

setae around macroseta on each basolateral lobe and 4 basal setae (Fig. 22). Dorsal side of dens with six setae and uniform granulation. Mucro long and straight (mucro: dens = 0.4–0.5

: 1), lateral lamellae subequal, long and not particularly high, basal part granulated ( Fig. 34 ),

ventral side with a keel reaching tip ( Fig. 35 ).

Upper subcoxae of all legs covered by tiny and numerous setae similar to dorsal ones,

other parts of legs with a usual number of longer setae. Legs 1–3 with 0, 2, 2 setae on lower subcoxae, 3, 7, 8 setae on coxae, 6, 6, 5–6 on trochanters, 13, 11–12, 10–11 setae on femora and 19, 19, 18 setae on tibiotarsi, respectively. Unguis with a strong tooth in lower third of inner edge and a pair of lateral teeth subapically ( Figs 32–33 ), a small tooth also present on outer side of unguis ( Fig. 33 ). Empodial appendage absent.

REMARKS. The original description of the species (Uchida, 1940) and a colour illustration by the same author (1965) are the only existed ones. It provides only few details, namely:

size, colour pattern, number of ocelli and lobes in the PAO , the presence of a furca and of an inner tooth on the unguis, and the relative lengths of the mucro. Some additional details are clear from the accompanying figures: the shape of the mandible (fig. E in Uchida, 1940), the presence of a trilobed apical vesicle on the apex of the antennae (fig. H) and two inner sensilla in the AO (fig. I). Our specimens fit this description quite well. Two smaller colourless patches at the Th.2–3 border were not mentioned in the original description, but could be seen in the studied types. Only few inconsistencies worth mentioning were observed. The main of them are as follows: colour of patches is not pink or vivid pink as in Uchida (1940),

but orange in the live specimens from Mt. Hikosan ( Fig. 5 ), and the mucro is much longer in our specimens (~1/2 of dens vs 1/ 7 in the text or 1/5, according to fig. F in Uchida). We checked the type materials of C. yasumatsui , but unfortunately only few details could be observed. The positions of the dens and mucro allow no correct measurement to be taken, but the mucro in the type material is clearly longer than illustrated by Uchida.

No specimens studied have any traces of a genital orifice and, despite their large sizes,

they all are clearly juveniles. However, the above description of most morphological characters is likely to hold for adults as well. Only some quantitative details should be taken with caution. Among them, for example, are the presence of only 3+3 setae on VT which is a common juvenile characteristic in the related genus Pseudachorutes and, apparently, a certain number of antennal sensilla and setae, which may also depend on age.

nearest ocelli; 28 – labium; 29 – labrum; 30 – mandible; 31 – head of maxilla; 32 – tibiotarsus and unguis of leg 3; 33 – unguis, outer side; 34–35 – mucro, dorsal and ventral views. Scales:

Figs 23, 25, 28–29, 32–33 – 0.1 mm, 24, 26–27, 30–31, 34–35 – 0.01 mm.

DISTRIBUTION AND ECOLOGY. Ceratrimeria yasumatsui is known from three neighboring prefectures: Fukuoka, Miyazaki and Oita (see Hasegawa & Tanaka, 2013), and appears to be widespread on the island of Kyushu. Like the previous species, it mainly inhabits cavities under bark of dead trees and also rotten wood.

Figures

Figs 1–6. Ceratrimeria takaoensis (1–2) and C. yasumatsui (3–6): 1 – alive specimens

Figs 7–12. Dorsal chaetotaxy of Ceratrimeria yasumatsui (7–10) and C. takaoensis (11–

Figs 23–35. Ceratrimeria yasumatsui: 23 – Ant.3–4, dorsal side; 24 – tip of Ant.4; 25 – Ant.3–4, ventral view; 26 – inner sensilla of AO covered by cuticular fold; 27 – PAO and