Pseudechiniscus asper Abe, Utsugi & Takeda, 1998
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publication ID |
https://dx.doi.org/10.3897/zse.96.53324 |
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publication LSID |
lsid:zoobank.org:pub:F79B0B2D-728D-4A3D-B3C3-06A1C3405F00 |
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persistent identifier |
https://treatment.plazi.org/id/9C5B4D9A-664A-5BEB-8BEF-EEB1E02ED71D |
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treatment provided by |
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scientific name |
Pseudechiniscus asper Abe, Utsugi & Takeda, 1998 |
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Pseudechiniscus asper Abe, Utsugi & Takeda, 1998 Figures 1 View Figure 1 , 2 View Figure 2 , 5A View Figure 5 , Tables 2, 3
Locus typicus and type material.
ca. 42°46'N, 141°24'E, 250 m a.s.l.; vicinity of the Lake Shikotsu (Chitose, South-western Hokkaido, Japan); foliose lichen Phaeophyscia imbricata ( Physciaceae) on the trunk of a maple ( Acer japonicum ). Collector: Kazuo Utsugi. Holotype: adult male on the slide NSMT-Tg 44 deposited in the National Museum of Nature and Science in Tokyo.
Additional material. Four females on the slides JP.012.01, JP.013.01-2, JP.014.01 and a male on the slide JP.012.04. Hologenophores: JP.012.01, 4, JP.013.02.
Etymology.
From Latin asper = rough, referring to the irregular surface of dorsal plates. Adjective in the nominative singular.
Description.
Mature females (i.e. from the third instar onwards; measurements in Table 2 View Table 2 ). Body dark orange, with round black eyes present or dissolving soon after mounting (Fig. 1A, B View Figure 1 ). Member of the suillus-facettalis complex: dome-shaped (hemispherical) cephalic papillae (secondary clavae) and minute (primary) clavae; peribuccal cirri with poorly developed cirrophores. Cirrus A short, with cirrophore.
Dorsal plates well-sclerotised as for a Pseudechiniscus species, clearly demarcated from each other, with Pseudechiniscus -type sculpturing, i.e. large endocuticular pillars protruding through the epicuticle and visible as dark dots in PCM (Fig. 2A View Figure 2 ). Striae absent. The cephalic plate pentapartite, with the anterior bi-halved portion and three posterior portions, roughly equal in size (Fig. 1A, B View Figure 1 ). The cervical (neck) plate absent. The scapular plate with a transverse suture, separating a broader anterior portion and narrower posterior portion (Figs 1B View Figure 1 , 2A View Figure 2 ). Three median plates: m1-2 bipartite, with much reduced, narrow posterior portions, m3 unipartite and large (Fig. 2A View Figure 2 ) with two pairs of lateral intersegmental platelets flanking the borders of m1-2. Two pairs of large segmental plates, their posterior portions exhibiting thickenings at positions C and D - the latter usually more pronounced (Figs 1A, B View Figure 1 , 2 View Figure 2 ). The pseudosegmental plate IV’ divided by a median longitudinal suture; the posterior margin of the plate with a pair of short triangular projections (Figs 1A, B View Figure 1 , 2A View Figure 2 ). The caudal (terminal) plate with short incisions that may be sclerotised (compare Fig. 1A View Figure 1 with Fig. 1B View Figure 1 ).
Ventral cuticle with a faint species-specific pattern reaching the lateroventral sides of the body (Figs 2B View Figure 2 , 5A View Figure 5 ), being a typical reticulum composed of large multiangular, longitudinal shapes connected by belts of pillars. Pillars are particularly poorly visible between legs I and II (Fig. 2B View Figure 2 ). The subcephalic zone with a wide patch of pillars (Fig. 5A View Figure 5 ). Sexpartite gonopore located anteriorly of legs IV and a trilobed anus between legs IV.
Pedal plates and dentate collar IV absent; instead, large patches of pillars are present centrally on each leg (Fig. 1A, B View Figure 1 ). Pulvini indistinct. No papilla or spine on leg I visible in PCM, a papilla on leg IV present (Figs 1B View Figure 1 , 2 View Figure 2 ). Claws IV higher than claws I-III; internal claws with needle-like spurs positioned at ca. 1/4-1/5 of the claw height (Fig. 1A View Figure 1 , insert).
Mature males (i.e. from the second instar onwards; measurements in Table 3 View Table 3 ). Smaller than females, with slender body (Fig. 1C View Figure 1 ). Cirri externi approaching the length of cirri A. Pseudosegmental projections in the form of teeth or wide lobes. Gonopore circular.
Juveniles. Unknown.
Larvae. Unknown.
Eggs. Unknown.
DNA sequences.
Single haplotypes in 18S rRNA (MT645083, 843 bp), 28S rRNA (MT645081, 716 bp) and ITS-1 (MT645085, 631 bp) were obtained.
Remarks.
This is the third record of this very rare species, which, in addition to the type locality, has also been found on Mount Taibai, Shaanxi, China ( Li et al. 2005). In the original description, only one male was found to possess triangular projections, ending with papillate tips, on the pseudosegmental plate ( Abe et al. 1998). However, the variability in the shape of the pseudosegmental projections has previously been noted ( Fontoura et al. 2010), thus the lobate form of these structures in the Chinese and Japanese (Honshu) specimens is not surprising. Moreover, Abe et al. (1998) did not illustrate the complete ventral pattern of this species (most likely because of the quality of the microscope used) and omitted the swelling or thickening of the armour at position C, which is weakly developed in this species. As Asamushi lies only ca. 200 km southwards from the shores of Lake Shikotsu (however, the Blakiston’s Line was designated to separate faunae of large vertebrates of Honshu and Hokkaido; see Kawamura 2007), the formal amendments to the original description presented here are justified given that DNA barcodes compensate the scarcity of specimens used in morphometrics.
Phenotypic differential diagnosis.
Taxa most similar to P. asper , i.e. those possessing pseudosegmental projections, can be easily distinguished from this species, based on the presence of striae (even rudimentary striae are absent in P. asper ; see Fig. 2 View Figure 2 in Fontoura et al. 2010 for microphotographs of other species), and/or by the lack of thickenings at the lateral positions ( Abe et al. 1998).
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