Tetrastemma shohoense, Hookabe & Kohtsuka & Fujiwara & Tsuchida & Ueshima, 2023
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publication ID |
https://dx.doi.org/10.3897/zookeys.1146.95004 |
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publication LSID |
lsid:zoobank.org:pub:84DB1223-8E0F-4837-BFD2-5616E692DAF1 |
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persistent identifier |
https://treatment.plazi.org/id/9D1CD900-900F-4114-8853-16C480FDD75D |
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taxon LSID |
lsid:zoobank.org:act:9D1CD900-900F-4114-8853-16C480FDD75D |
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treatment provided by |
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scientific name |
Tetrastemma shohoense |
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sp. nov. |
Tetrastemma shohoense sp. nov.
Fig. 2E-I [New Japanese name: shoho-kakubari-himomushi] View Figure 2
Etymology.
The species is named after the type locality, Shoho Seamount of the Nishi-Shichito Ridge, Japan.
Material examined.
Holotype: NMST-Nem-H-05, unsectioned complete specimen except for the posterior tip, fixed in Bouin’s fluid, posterior tip preserved in 99% ethanol, collected on November 29 2020 by NH, by use of ROV KM-ROV (dive #123) during KM20-10C cruise of R/ V Kaimei, at a depth of 455 m, near the summit of Shoho Seamount of the Nishi-Shichito Ridge (32°19.39'N, 138°44.48'E), Japan, NW Pacific. GoogleMaps
Description.
Head spatulate in profile (Fig. 2E-H View Figure 2 ), not well demarcated from body by anterior cephalic furrows (Fig. 2E View Figure 2 ). Before anesthetization, body of a live specimen 5.5 mm long and 0.3 mm wide. Background body color generally white, tinged with bright yellow to orange, and almost transparent (Fig. 2E View Figure 2 ). Head with a red rectangle cephalic patch without extending behind a posterior pair of eyes (Fig. 2E, H View Figure 2 ). Anterior pair of cephalic furrows present (Fig. 2F View Figure 2 ) but posterior one not well distinguished. Cerebral ganglia and blood uncolored (Fig. 2G, H View Figure 2 ). Alimentary canals visible as bright yellow organs through body wall (Fig. 2E View Figure 2 ). Proboscis pale, extending about 3/4 of the body length (Fig. 2E View Figure 2 ). Four brown eyes present; anterior pair slightly larger than posterior ones (Fig. 2H View Figure 2 ).
Stylet basis cylindrical, 55.0 μm in length and 25.0 μm in maximum width; central stylet smooth, 47.0 μm in length; (stylet length) / (basis length) ratio 0.85 (Fig. 2I View Figure 2 ). Two accessory stylet pouches present, each containing two stylets (Fig. 2I View Figure 2 ).
Type locality and distribution.
The species is only known from the type locality, Shoho Seamount of the Nishi-Shichito Ridge, Japan, at a depth of 455 m (Fig. 1 View Figure 1 ), among the sandy sediments on rocky substrates.
Remarks.
Having a dark cephalic patch and cylindrical stylet basis and lacking a longitudinal line on the dorsal surface of the body, T. shohoense sp. nov. resembles T. freyae Chernyshev et al., 2020 originally described based on Hawaiian and Indian specimens. The new species is differentiated from T. freyae in the color of the cephalic patch as well as the non-flared posterior margin of the cylindrical stylet basis.
A genetic distance based on COI between T. shohoense sp. nov. and T. freyae (specimens from Hawaii (MT247877) and India (MT247878) was 12.6%; the value is comparable with interspecific values observed among Monostilifera (e.g., Sundberg et al. 2016; Hookabe et al. 2022).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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