Tritonia psoloides Aurivillius, 1887
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https://doi.org/ 10.1007/s13127-021-00526-8 |
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lsid:zoobank.org:pub:6A397FB3-2799-4A1C-A0A2-11B2190DCE08 |
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persistent identifier |
https://treatment.plazi.org/id/42524C25-DB2D-FFD5-FF4B-852AEFF5FEB8 |
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treatment provided by |
Felipe |
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scientific name |
Tritonia psoloides Aurivillius, 1887 |
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Tritonia psoloides Aurivillius, 1887 View in CoL
( Fig. 7C View Fig )
Material studied: MIMB 42245 View Materials , Bering Sea, 61°10′40.1″ N, 174°52′14.9″ E, depth 418 m, June 28, 2018 GoogleMaps , R / V Akademik Lavrentyev, 1 specimen .
External morphology: Body length up to 280 mm. Body elongate, broad, tapering towards posterior end. Up to 18 bi- or tripinnate branched dorsolateral appendages. Dorsal side smooth to slightly rugose. Seventeen conical appendages on oral veil. Rhinophores elongate and narrow, surrounded by 6 tripinnate papillae. Rhinophoral sheaths low, simple. Anal opening on right side mid-length, reproductive opening on right side at anterior 1/4 of body length.
Color: Uniform milky-white with opaque-white tips of appendages.
Internal morphology: The single specimen was not available for study of internal morphology since this large formalin-fixed specimen is a part of permanent exposition in the Museum of National Scientific Center of Marine Biology.
Molecular data: On the phylogenetic reconstruction based on three markers (COI, 16S, H3), the specimen here examined is genetically identical to Tritonia cf. psoloides (CASIZ181055) from the eastern part of the Bering Sea (ML= 7 0; PP= 1) ( Fig. 4C View Fig ). This lineage is sister to the Tritonia tetraquetra clade (ML= 87; PP = 1). The p- distance in COI marker between these two species ranges between 8.1 and 9.1%.
Distribution: So far only known from the Bering Sea, 140–418 m depth ( Korshunova & Martynov, 2020; present study).
Biology: Community of sea urchins Brisaster latifrons (A. Agassiz, 1898) . Local seep activity, marked by bacterial tufts and dark bioturbated sediments. Common components of this community include anemones of the genus Monactis and the families Actinostolidae and Sagartiidae , as well as hermit crabs and gastropods. Sea pens are absent from active seep sites; however, they are very abundant components of their distant vicinity.
Remarks: The morphological data of the type specimen of T. psoloides were given in a recent comprehensive review of the family Tritoniidae ( Korshunova & Martynov, 2020) . Since this species was described from the Bering Sea (61°45′N 180°W), and a specimen genetically distinct from T. tetraquetra was found in the same sea, it was suggested to retain the species name T. psoloides as valid for that specimen. Although we were not able to study the internal morphology, our specimen matches T. psoloides type specimen in external morphology and coloration ( Korshunova & Martynov, 2020) and was collected close to the type locality of this species (appr. 250 km). Also, our specimen is similar genetically to GB specimen identified as Tritonia cf. psoloides from the Bering Sea. Therefore, we conclude that our data agrees with Korshunova and Martynov (2020) view and T. psoloides is regarded a valid species.
Superfamily Dendronotoidea Allman, 1845
Family Dendronotidae Allman, 1845
Genus Dendronotus Alder & Hancock, 1845 Dendronotus dalli Bergh, 1879
( Fig. 8 View Fig )
Material examined: MIMB 42233 View Materials , Sea of Okhotsk , Urup Is., 46°16′7″ N 150°16′5″ E, depth 227– 210 m, August 18, 2019, 1 specimen, 29 mm length GoogleMaps . MIMB 42234 View Materials , Sea of Okhotsk , Sakhalin Is., 52°12′4″ N 144°26′8″ E, depth 218– 192 m, July 30, 2019, 8 specimens, from 12 to 38 mm length GoogleMaps .
External morphology ( Fig. 8A–C View Fig ): Body up to 53 mm long, laterally compressed, elongate. From 6 to 10 oral appendages, 5 rhinophoral sheath appendages, lateral papilla present, 4–6 pairs of dorsolateral appendages. All appendages with 2–3 main stalks and extensive secondary branching, tertiary branches rare if present. Anal opening on right side of body about midway between first and second pairs of dorsolateral processes. Reproductive openings placed laterally near first pair of dorsolateral processes on right side.
Color ( Fig. 8A–C View Fig ): Milky-white to pink, with opaque white pigment on tips of dorsolateral, rhinophore sheaths and oral appendages.
Anatomy: Jaws elongated plates with strong dorsal process and slightly curved masticatory border ( Fig. 8D View Fig ), bearing a single row of denticles ( Fig. 8E View Fig ). Radular formula in studied specimens 33–36× 11–12.1.11–12 ( Fig. 8F View Fig ). Rachidian tooth triangular, smooth in adults ( Fig. 8G View Fig ). Lateral teeth elongated narrow plates, slightly curved, with large sharp cusp and 3–4 small denticles at its base ( Fig. 8H View Fig ). Cusp length decreases toward outer teeth. Innermost teeth thin, curved. Outermost teeth plate-like, 2–3 in number. Reproductive system triaulic. Large, folded ampulla with broadening mid-length. Prostate with small number of alveolar glands. Distal part of vas deferens short, expanding into a slightly curved penis. Vagina convoluted, gradually narrows into rounded bursa copulatrix. Small receptaculum seminis near distal part of vagina.
Molecular data: Our phylogenetic reconstruction based on the 4 markers (COI, 16S, H3 and 28S) indicates all Dendronotus dalli specimens are clustered together into a single highly supported group (PP= 1; ML = 93) ( Fig. 9A View Fig ). This confirms identity of studied specimens from the Sea of Okhotsk. On the phylogenetic tree, D. dalli specimens display intraspecific structure with three internal clades, which correspond haplogroups on the haplotype network ( Fig. 9B View Fig ). All studied specimens from the Sea of Okhotsk represent a single haplogroup B, which differs by 9 substitutions from members of the haplogroup A (specimens from the shallow Chukchi Sea) and by 7 substitutions from the haplogroup C (specimens from shallow waters near Kamchatka and British Columbia). to the geographic origin of each haplotype. The relative size of circles is proportional to the number of sequences of that same haplotype. C, Dendronotus patricki, COI haplotype network (above-left) and haplotype network of predicted 18S haplotypes (below-right), produced with TCS method in PopART. Colors of circles refer to the geographic origin of each haplotype. The relative size of circles is proportional to the number of sequences of that same haplotype
Biology: This species was collected from two localities on the upper continental slope near Sakhalin Is. (1) and near Urup Is., a part of the Kuril Islands (2). In both cases bottom sediments were composed of hard sand gravel. The ecological community in the locality near Sakhalin Is. is represented by echinoderms, with Strongylocentrotus droebachiensis (O.F. Müller, 1776) , Crossaster papposus (Linnaeus, 1767) , Henricia sp. , and large unidentified Crinoidea as dominant species. Urup Is. gravel community includes numerous demosponges, hydrozoans and gorgonians, and a species-rich benthic epifauna.
Distribution: This species displays a wide bathymetric and geographical range, including shallow and upper bathyal areas in the Sea of Japan, the Sea of Okhotsk, the Bering Sea, the Northwest Pacific, from Alaska to British Columbia ( Ekimova et al., 2015; Korshunova et al., 2020a), and was also recently found in the Arctic region in the Chukchi Sea ( Ekimova et al., 2019).
Remarks: Molecular data indicates divergence into three mitochondrial haplogroups corresponding to inhabitants of different bathymetric zones and biogeographical areas ( Fig. 9A, B View Fig ). Same groups form distinct clades on the phylogenetic reconstructions. However, these specimens represent uniform morphological traits and are not so diverged genetically to be considered a cryptic species. This genetic population structure is most likely a result of temporary isolation into subpopulations that occurred in recent past.
Dendronotus patricki Stout, N. G. Wilson & Valdés, 2011
( Figs. 3C View Fig and 10 View Fig )
Material examined: MIMB 42239 View Materials , Sea of Okhotsk , Sakhalin Is., 49°10′4″ N 145°03′1″ E, depth 262–266 m, July 29, 2019, 1 specimen GoogleMaps . MIMB 42240 View Materials , Sea of Okhotsk , Sakhalin Is., 49°10′4″ N 145°03′1″ E, depth 262–266 m, July 29, 2019, 1 specimen GoogleMaps . MIMB 42241 View Materials , Sea of Okhotsk , Sakhalin Is., 52°45′0″ N 144°24′3″ E, depth 261–282 m, July 30, 2019, 1 specimen GoogleMaps .
External morphology ( Fig. 10A–D View Fig ): Body broad, up to 41 mm in length. Large oral veil with up to 9 poorly branched oral appendages, 5 rhinophoral sheath appendages, lateral papilla absent, 5 to 6 pairs of dorsolateral appendages. Appendages stout with large primary stalk and extensive secondary and tertiary branching. Anal opening on right side of body about midway between first and second pairs of dorsolateral processes. Reproductive openings placed laterally near first pair of dorsolateral processes on right side.
Color ( Fig. 10A–D View Fig ): Light pink to brownish. Opaque white large dots covering notum, dorsolateral and oral appendages. Digestive gland visible through skin, variable in color in different specimens from light pink to black.
Anatomy: Jaws oval-shaped plates with strong dorsal process and slightly curved masticatory border, bearing at least three rows of small conical denticles ( Fig. 10E, F View Fig ). Radular formula in studied specimens 30×12.1.12 ( Fig. 10G View Fig ). Rachidian tooth triangular, with strong conical cusp and 9–14 small denticles on each side ( Fig. 10H, I View Fig ). Lateral teeth triangular, slightly curved, lacking denticles in most cases ( Fig. 10J View Fig ). Innermost lateral teeth subulate, some possess 1–2 reduced denticles. Reproductive system triaulic ( Fig. 3C View Fig ). Ampulla large, muscular, convoluted. Relatively long narrow proximal part of vas deferens lead to prostate composed of 22 small alveolar glands. Distal part of vas deferens muscular and very convoluted, expanding to slightly curved, large penile sheath. Penis elongated. Vagina folded in midline, gradually narrowing into rounded muscular bursa copulatrix. Small receptaculum seminis near distal part of vagina.
Molecular data: Our phylogenetic reconstruction based on the 4 markers (COI, 16S, H3 and 28S) indicates all Dendronotus patricki specimens are clustered together into a single highly supported group (PP = 1; ML = 90) ( Fig. 9A View Fig ). This confirms identity of studied specimens from the Sea of Okhotsk. The COI haplotype network ( Fig. 9C View Fig ) showed that the type specimen D. patricki from the NE Pacific has 12 substitutions from the Northwest Pacific and the Arctic specimens (p- distance 1.7%). The rest specimens are differed by 1–3 substitutions, with no geographical structure. Analysis of nuclear 18S showed its similarity among all studied specimens (from all localities), with several cases of heterozygous sites: in the positions 654 (C/T in WS9105, MIMB 42239, MIMB 42240; C in others), 679–680 (AA/GG in WS9104, WS9105, MIMB 42240; AA/AG in WS9106; AA in others), 685 (C/T in WS9104, WS9105, MIMB 42240; T in others), and 712 (C/T in WS9104-WS9106, MIMB 42240; T in others). This suggests geneflow across population of distant geographical areas.
Biology: This species was collected in two localities, both composed of fine muddy sand. Other benthic species found in the localities are typical members of the muddy sand community, including Nuculana bivalves, Crossaster sea stars and other echinoderms, numerous shrimps and hermit crabs, sedentary annelids, and buccinid gastropods.
Distribution: According to our data, this species has a wide bathymetric and geographic range, encompassing bathyal and abyssal areas of the Arctic ( Ekimova et al., 2019), the NE Pacific ( Stout et al., 2011), and the Northwest Pacific ( Martynov et al., 2020; present study).
Remarks: Dendronotus patricki was originally described from 1819 m in depth, Monterey Canyon, NE Pacific ( Stout et al., 2011). It was also reported from the bathyal zone of Arctic waters ( Ekimova et al., 2019). The present study shows that its distribution now includes the Northwest Pacific. Recently, the new species Dendronotus bathyvela Martynov, Fujiwara, Tsuchida, R. Nakano, N. Sanamyan, K. Sanamyan, Fletcher & Korshunova, 2020 was described based on morphological data only ( Martynov et al., 2020) from the same geographic area ( Japan, off the Pacific coast of Northern Honshu, 303–307 m in depth). This species was suggested to have notable differences from Dendronotus patricki original species description ( Stout et al., 2011), i.e., in the coloration and the radular characters. The coloration pattern of the type specimen of D. patricki is uniform pinkish body color, while in D. bathyvela it is brown with opaque white dots. Our specimens of D. patricki have pinkish or brown coloration and numerous white dots on the dorsum ( Fig. 10A–D View Fig ). Regarding radular characters, D. bathyvela has up to 14 lateral teeth on both sides and up to 30 denticles on the rachidian tooth. In our specimens of D. patricki , there are up to 28 denticles on each side of the rachidian tooth. It should be also mentioned that the D. patricki paratype has 11 lateral teeth on each side ( Stout et al., 2011: Fig. 4A View Fig ) and up to 30 denticles on the rachidian tooth ( Stout et al., 2011: Fig. 4B View Fig ). Therefore, our data demonstrates D. patricki has a considerable range of morphological variability encompassing the diagnosis of D. bathyvela . Unfortunately, molecular data for D. bathyvela are not available. However, taking into consideration the morphological similarities of our specimens and the type specimens of D. bathyvela , the proximity of collection the localities of D. patricki in the Northwest Pacific to the type locality of D. bathyvela , and the molecular similarities of the studied specimens, we suggest to consider D. bathyvela as a synonym of D. patricki .
( Fig. 11 View Fig )
Material studied: MIMB 42242 View Materials , Sea of Okhotsk , Shiashkotan Is., 48°48′3″ N 154°17′7″ E, depth 285–304 m, August 12, 2019, 1 specimen GoogleMaps . MIMB 42243 View Materials , locality, depth and date same as MIMB 42242 View Materials , 1 specimen . MIMB 42244 View Materials , locality, depth and date same as MIMB 42242 View Materials , 1 specimen .
External morphology ( Fig. 11A, B View Fig ): Body up to 52 mm long, laterally compressed, elongate. From five to six oral appendages, five rhinophoral sheath appendages, lateral papilla present, 5–6 pairs of dorsolateral appendages. All appendages with 2–3 main stalks and extensive secondary branching, tertiary branches rare if present. Anal opening on right side of body about midway between first and second pairs of dorsolateral processes. Reproductive opening located laterally near first pair of dorsolateral processes on right side.
Color ( Fig. 11A, B View Fig ): Background color varies from translucent milky-white with an orange tinge to variegated orange-brown. In pale specimens, body pigmentation formed by narrow brown lines on dorsolateral sides between appendages of each row and few white opaque dots. In variegated specimens these lines and dots well visible. Oral veil, rhinophoral and dorsolateral appendage tips orange to brown sometimes with opaque white pigment inside branches.
Anatomy: Jaws elongated plates with strong dorsal process and slightly curved masticatory border ( Fig. 11C View Fig ), bearing a single row of denticles ( Fig. 11D View Fig ). Radular formula in studied specimens 29× 8–10.1.8–10 ( Fig. 11E, F View Fig ). Rachidian tooth smooth. Lateral teeth elongate, narrow, slightly curved with up to 12 denticles. Inner- and outermost lateral teeth subulate. Reproductive system triaulic. Ampulla relatively small, bent mid-length. Prostate with up to 25 alveoli. Distal vas deferens long and winding, narrowing slightly into curved ejaculatory portion. Wide vagina gradually narrows into muscular bursa copulatrix, receptaculum seminis small, indistinct.
Molecular data: Our phylogenetic reconstruction based on 4 markers (COI, 16S, H3, and 28S) clusters all Dendronotus zakuro specimens together into a single highly supported group (PP= 1; ML = 96) ( Fig. 9A View Fig ). This confirms the identity of studied specimens from deep waters. Intraspecific p- distance of COI marker is 0.9%.
Biology: This species was found in a species-rich community of gravel sand, composed of numerous echinoderms, annelids, sponges, and hydrozoans.
Distribution: Northwest Pacific: Japan, Kamchatka, up to 20 m in depth ( Martynov et al., 2020); the Kuril islands, 285–300 m in depth (present study).
Remarks: The species Dendronotus zakuro was recently described from the subtidal zone in two distant geographic localities ( Japan and Kamchatka). Our data provide a link between these localities and expand the known bathymetric range of this species to the deep-sea shelf and upper bathyal areas. Our specimens show a different coloration pattern from the type specimens: the latter have bright red to reddish-brown coloration, while the Kuril island specimens are much paler ( Fig. 11A, B View Fig ). This may cause identification difficulties as the same variety in variegated coloration is characteristic of D. kamchaticus Ekimova, Korshunova, Schepetov, Neretina, Sanamyan & Martynov, 2015 ( Ekimova et al., 2016a; Korshunova et al., 2016), which also has a similar radular morphology.
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Departamento de Geologia, Universidad de Chile |
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Royal British Columbia Museum - Herbarium |
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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