Scutopus schanderi, Saito & Salvini-Plawen, 2014
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publication ID |
https://doi.org/ 10.1080/00222933.2014.959577 |
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publication LSID |
lsid:zoobank.org:pub:35D0830A-F351-4FC4-BCD1-FA3C2B697AE5 |
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DOI |
https://doi.org/10.5281/zenodo.10527225 |
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persistent identifier |
https://treatment.plazi.org/id/622696CD-A06E-4902-A4FB-4DE9A2651ADE |
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taxon LSID |
lsid:zoobank.org:act:622696CD-A06E-4902-A4FB-4DE9A2651ADE |
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treatment provided by |
Carolina |
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scientific name |
Scutopus schanderi |
| status |
sp. nov. |
Scutopus schanderi View in CoL sp. nov.
( Figures 2–3 View Figure 2 View Figure 3 )
Type locality
Western Wakasa Bay , between Kanmuri-jima Island and Ine Port, Tango Peninsula, southern Sea of Japan, 35°39.20 ′ N, 135°21.47 ′ E, 69 m. GoogleMaps
Type depository
Department of Zoology, National Museum of Nature and Science, Tsukuba.
Etymology
This species is named for the late Dr. Christoffer Schander (University of Bergen, Norway) who contributed much to increase our knowledge on aplacophoran molluscs.
Material examined
Holotype. NSMT-Mo 78588, ethanol preserved specimen, a part of sclerites and radula are mounted on slide glasses, body length 14.7 mm, 35°39.20 ′ N, 135° 21.47 ′ E, 69 m, 2 September 2010. Paratypes. #1: NSMT-Mo 78589, body length 12.0 mm, from type locality; #2–3: NSMT-Mo 78590–78591, body length 6.5– 10.8 mm, 35°45.11 ′ N, 135°20.43 ′ E, 96 m, 2 September 2010; #4–9: NSMT-Mo 78592–78597, body length 5.2–10.3 mm, 35°44.97 ′ N, 135°22.40 ′ E, 101–102 m, 2 September 2010; #10: NSMT-Mo 78598, body length 6.8 mm, 35°45.03 ′ N, 135° 20.21 ′ E, 95 m, 13 August 2012; #11–12: NSMT-Mo 78599–78600, body length 6.7– 9.0 mm, 35°45.20 ′ N, 135°20.20 ′ E, 96–98 m, 25 October 2012.
Description of holotype
Animal 14.7 mm long, slender, almost uniform in diameter along body; 0.7 mm in foregut or pharyngeal region (neck or prothorax), 0.75 mm in anterior midgut region (anterior trunk or metathorax), and 0.6 mm in prepallial region ( Figure 2A View Figure 2 ). Boundary between foregut and midgut regions usually demarcated by groove and by transition of internal colouration to dark greenish colour in midgut. Anterior midgut and midgut sac region with distinct groove of midventral suture line. Pedal shield (buccal plate, oral shield) postoral, but flanking mouth opening laterally ( Figure 2E View Figure 2 ).
Dominant sclerites covering dorsal, lateral and large part of ventral surfaces of midgut region, midgut sac region, and prepallial region roughly oar-blade shaped, pointed at tip, thin, flat, weakly keeled on midline near tip, often with 1–2 longitudinal fine grooves on each side of median keel, up to 100 µm long × 40 µm wide in anterior midgut sac region ( Figure 3H View Figure 3 ), gradually increasing in size posteriorly ( Figure 3I View Figure 3 ), up to 138 µm long × 46 µm wide in prepallial region ( Figure 3J View Figure 3 ). Sclerites of peribuccal region minute, oval, flat, 17–26 µm long × 11–12 µm wide ( Figure 3A, B View Figure 3 ), elongating posteriorly and narrowing distally in more posterior sclerites. Sclerites in foregut region of two types: one similar to dominant sclerites, but with distinct waist, up to 80 µm long × 28 µm wide ( Figure 3C, E View Figure 3 ), the other more slender, with width of base narrower than widest point of distal half ( Figure 3D View Figure 3 ). Sclerites along midventral suture narrow in distal half, widening in proximal half, pointed at tip, keeled on midline near tip, measuring up to 115 µm long × 25 µm wide ( Figure 3F View Figure 3 ). Similar but wider sclerites provided with lateral sides of those narrow sclerites ( Figure 3G View Figure 3 ). Posterior margin of pallial region with narrow lanceolate sclerites that are broadly keeled in distal half, up to 165 µm long × 23 µm wide ( Figure 3K View Figure 3 ). Small narrow lanceolate sclerites, up to 90 µm long × 14 µm wide ( Figure 3L View Figure 3 ), inside pallial margin.
Radula large, c. 680 µm long, distichous, arranged in eight transverse rows, heavily sclerotized except for posteriormost two pairs; each tooth gaff- or hookshaped, c. 280 µm long, with 16–18 small, pointed median denticles ( Figure 2F, G View Figure 2 ).
Additional description from paratypes
Colour of living animals through translucent body wall dark green in midgut region and light brown with numerous yellowish green maculations in midgut sac area ( Figure 2B View Figure 2 ). Brownish colour of sclerotized radula observable through body wall ( Figure 2C View Figure 2 , arrow). Greenish colouration faded out in preserved specimens ( Figure 2A, D View Figure 2 ). Radula teeth less sclerotized in small specimen ( Figure 2H View Figure 2 , paratype #5).
Remarks
The genus Scutopus is considered to be the most conservative representative in the Caudofoveata because of a postoral pedal shield, ventral suture line of fusion of the mantle edges in most species, body wall musculature, distichous radula without any lateral cuticular apparatus, and, in males, the pallial mucous tracts. So far, only four species of the genus Scutopus are known from three areas: S. ventrolineatus Salvini- Plawen, 1968 and S. robustus Salvini-Plawen, 1970 from the Eastern Atlantic ( Salvini-Plawen 1968, 1970); S. megaradulatus Salvini-Plawen, 1972 from the Caribbean Sea; and S. chilensis Salvini-Plawen, 1972 from off the East Pacific Chilean coast. The new species Scutopus schanderi most resembles S. robustus in possessing heavily sclerotized radula teeth with denticles up to the tip, but differs from the latter by having fewer radula denticles in adult individuals: 16–18 in S. schanderi , 20–22 (13–22) in S. robustus ; other characters in contrast to the 8–12 mm long, more stoutish S. robustus are also the wider, subparallel-sided dominant sclerites, the presence of the midventral mantle suture and the slender body shape in S. schanderi .
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