Mastigoniscus minimus Wenz, Knauber & Riehl, 2024

(SOSA), Senckenberg Ocean Species Alliance, Brandt, Angelika, Chen, Chong, Engel, Laura, Esquete, Patricia, Horton, Tammy, Jażdżewska, Anna M., Johannsen, Nele, Kaiser, Stefanie, Kihara, Terue C., Knauber, Henry, Kniesz, Katharina, Landschoff, Jannes, Lörz, Anne-Nina, Machado, Fabrizio M., Martínez-Muñoz, Carlos A., Riehl, Torben, Serpell-Stevens, Amanda, Sigwart, Julia D., Tandberg, Anne Helene S., Tato, Ramiro, Tsuda, Miwako, Vončina, Katarzyna, Watanabe, Hiromi K., Wenz, Christian & Williams, Jason D., 2024, Ocean Species Discoveries 1 – 12 — A primer for accelerating marine invertebrate taxonomy, Biodiversity Data Journal 12, pp. e 128431-e 128431 : e128431-

Mastigoniscus minimus Wenz, Knauber & Riehl sp. nov.

Materials

Type status: Holotype. Occurrence: catalogNumber: SMF 56475 ; recordNumber: KB 2 Hap 193; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: male; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782632.1; occurrenceID: A82AEA3B-B81A-55EF-BCA1-F8EB9D0106AB; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, abyssal plains southeast of the Trench, KuramBio II expedition, station SO 250-008 ; verbatimDepth: 5136 m; decimalLatitude: 43.82; decimalLongitude: 151.77; Identification: identificationID: KB 2 Hap 193; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 19 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-008; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Paratype. Occurrence: catalogNumber: SMF 56301 ; recordNumber: KB 2 Hap 003; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: male; lifeStage: adult; preparations: EtOH 96 %; occurrenceID: 56A6E05A-D536-5612-BC62-19F348987A7A; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, abyssal plains southeast of the Trench, KuramBio II expedition, station SO 250-008 ; verbatimDepth: 5136 m; decimalLatitude: 43.82; decimalLongitude: 151.77; Identification: identificationID: KB 2 Hap 003; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 19 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-008; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Paratype. Occurrence: catalogNumber: SMF 56477 ; recordNumber: KB 2 Hap 195; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782636.1; occurrenceID: 267360E1-3628-5C3D-BC7F-7EB68A09EF54; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, abyssal plains southeast of the Trench, KuramBio II expedition, station SO 250-008 ; verbatimDepth: 5136 m; decimalLatitude: 43.82; decimalLongitude: 151.77; Identification: identificationID: KB 2 Hap 195; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 19 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-008; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56413 ; recordNumber: KB 2 Hap 131; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782634.1; occurrenceID: 0E3A6E43-357E-5BEA-8B2E-E8279CD5A66C; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-040 ; verbatimDepth: 7081 m; decimalLatitude: 45.66; decimalLongitude: 152.95; Identification: identificationID: KB 2 Hap 131; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 29 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-040; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56449 ; recordNumber: KB 2 Hap 167; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782627.1; occurrenceID: 829CC624-DDCF-5743-9531-7EEBB6E91D5E; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-097 ; verbatimDepth: 6575 m; decimalLatitude: 44.11; decimalLongitude: 151.41; Identification: identificationID: KB 2 Hap 167; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 18 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-097; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56450 ; recordNumber: KB 2 Hap 168; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782639.1; occurrenceID: D91C900F-69B0-5842-80B8-0A49A7CB1CB3; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-097 ; verbatimDepth: 6575 m; decimalLatitude: 44.11; decimalLongitude: 151.41; Identification: identificationID: KB 2 Hap 168; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 18 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-097; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56451 ; recordNumber: KB 2 Hap 169; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782638.1; occurrenceID: 15EC7754-BA81-5EF6-A91D-DC12C56C5C27; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-097 ; verbatimDepth: 6575 m; decimalLatitude: 44.11; decimalLongitude: 151.41; Identification: identificationID: KB 2 Hap 169; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 18 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-097; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56452 ; recordNumber: KB 2 Hap 170; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782641.1; occurrenceID: 0997E606-4FA8-50DB-AC35-E4312B0998A3; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-097 ; verbatimDepth: 6575 m; decimalLatitude: 44.11; decimalLongitude: 151.41; Identification: identificationID: KB 2 Hap 170; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 18 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-097; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56453 ; recordNumber: KB 2 Hap 171; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782630.1; occurrenceID: 87A48BC7-B676-580B-87A6-9211B44DB18A; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-097 ; verbatimDepth: 6575 m; decimalLatitude: 44.11; decimalLongitude: 151.41; Identification: identificationID: KB 2 Hap 171; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 18 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-097; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56454 ; recordNumber: KB 2 Hap 172; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: male; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782640.1; occurrenceID: 849B456A-A547-5E8D-A442-273357A9D955; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-098 ; verbatimDepth: 6446 m; decimalLatitude: 44.10; decimalLongitude: 151.42; Identification: identificationID: KB 2 Hap 172; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Agassiz Trawl; eventDate: 19 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-098; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56455 ; recordNumber: KB 2 Hap 173; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782626.1; occurrenceID: 907C249F-D568-5FF0-A044-D45B6A2AC835; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-098 ; verbatimDepth: 6446 m; decimalLatitude: 44.10; decimalLongitude: 151.42; Identification: identificationID: KB 2 Hap 173; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Agassiz Trawl; eventDate: 19 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-098; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56456 ; recordNumber: KB 2 Hap 174; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: indet.; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782631.1; occurrenceID: 71F73D3E-D528-5FA2-BB3D-B0EE912584F8; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-098 ; verbatimDepth: 6446 m; decimalLatitude: 44.10; decimalLongitude: 151.42; Identification: identificationID: KB 2 Hap 174; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Agassiz Trawl; eventDate: 19 / 09 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-098; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56467 ; recordNumber: KB 2 Hap 185; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: female; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782635.1; occurrenceID: C6FF82AE-95BC-55DF-94D3-BBE39C464CDB; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-040 ; verbatimDepth: 7081 m; decimalLatitude: 45.66; decimalLongitude: 152.95; Identification: identificationID: KB 2 Hap 185; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 29 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-040; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56468 ; recordNumber: KB 2 Hap 186; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: indet.; lifeStage: manca; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782637.1; occurrenceID: CE077CCA-9C32-5800-B16B-98EC415E6794; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, hadal depths of the Trench, KuramBio II expedition, station SO 250-040 ; verbatimDepth: 7081 m; decimalLatitude: 45.66; decimalLongitude: 152.95; Identification: identificationID: KB 2 Hap 186; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 29 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-040; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56474 ; recordNumber: KB 2 Hap 192; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: male; lifeStage: juvenile; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782628.1; occurrenceID: 0B657B8D-6E83-525E-8E29-09E90D9CEF18; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, abyssal plains southeast of the Trench, KuramBio II expedition, station SO 250-008 ; verbatimDepth: 5136 m; decimalLatitude: 43.82; decimalLongitude: 151.77; Identification: identificationID: KB 2 Hap 192; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 19 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-008; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56476 ; recordNumber: KB 2 Hap 194; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: male; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782633.1; occurrenceID: FDC78104-8645-5F3E-B716-B9DD006ABBE8; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, abyssal plains southeast of the Trench, KuramBio II expedition, station SO 250-008 ; verbatimDepth: 5136 m; decimalLatitude: 43.82; decimalLongitude: 151.77; Identification: identificationID: KB 2 Hap 194; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Epibenthic Sledge; eventDate: 19 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-008; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: SMF 56478 ; recordNumber: KB 2 Hap 196; recordedBy: Angelika Brandt | Saskia Brix | Nils Brenke | Magdalena Blazewicz | Olga Golovan | Nele Heitland | Anna Jazdzewska | Karen Jeskulke | Gennady Kamenev | Anna Lavrenteva | Marina Malyutina | Torben Riehl; individualCount: 1; sex: male; lifeStage: adult; preparations: EtOH 96 %; associatedSequences: https://www.ncbi.nlm.nih.gov/nuccore/OM782629.1; occurrenceID: 975C0850-0B58-5D19-8BB9-ED01A9B10DE7; Taxon: scientificName: Mastigoniscus minimus Wenz, Knauber & Riehl ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Haploniscidae ; genus: Mastigoniscus ; specificEpithet: minimus ; taxonRank: species; scientificNameAuthorship: Wenz, Knauber & Riehl; nomenclaturalCode: ICZN; Location: waterBody: Northwest Pacific Ocean; locality: Kuril-Kamchatka Trench, abyssal plains southeast of the Trench, KuramBio II expedition, station SO 250-006 ; verbatimDepth: 5146 m; decimalLatitude: 43.82; decimalLongitude: 151.76; Identification: identificationID: KB 2 Hap 196; identifiedBy: Christian Wenz; dateIdentified: 2022; Event: samplingProtocol: Box Corer; eventDate: 18 / 08 / 2016; habitat: deep-sea sediment; fieldNumber: SO 250-006; Record Level: institutionCode: SMF; basisOfRecord: PreservedSpecimen

Description

Type material remarks: The adult male holotype ( SMF 56475), despite being less intact than the adult male paratype ( SMF 56301), was selected as such, based on the availability of a molecular barcode, which the male paratype lacks. When compared to known congeners, the pleopod 1 shape of the type material at hand presumably represents an adult male, but no terminal male stage. The pleopod 1 morphology is, therefore, most likely not fully developed and, thus, not included in the species diagnosis. As the holotype lacks the distal articles of antenna 2 beyond article 5, all antenna 2 characters have been scored based on the male paratype.

Description of the adult male holotype ( SMF 56475)

Body (Fig. 21 A and Fig. 22 A) length 1.6 mm, 2.1 width; oval, dorsoventrally elliptical. Anterior body length (Ceph + Prn 1–4) 0.90 posterior body length (Prn 5 – Plt). Lateral margin continuous; delicately serrated, setose from Prn 1 posterolateral margin through to Prn 5 anterolateral margin. Tergite surfaces tuberculate, ornamentation evenly distributed; convex cross-section of tergites broken by slight, uneven elevations at the muscle attachment points of pereopods, elevated areas without ornamentation. Non-conglobating.

Ceph (Fig. 21 A and Fig. 22 A) length 0.43 width, 0.15 body length, width 0.70 body width; trapezoidal, tergite surface tuberculate; anterolateral angles not projecting, rounded; frontal margin concave, width 0.42 Ceph width.

Prn 4 (Fig. 21 A and Fig. 22 A) posterolateral angle with minute, acute projection, lateral margin length 0.61 Prn 5 lateral margin length. Prn 5 (Fig. 21 A and Fig. 22 A) anterolateral angle with minute, acute projection. Prn 7 (Fig. 21 A and Fig. 22 A) cone-shaped, shorter and narrower than Prn 6; tergite medially conjoint with Plt, segment borders not expressed.

Plt (Fig. 21 A and Fig. 22 A) length 0.33 body length; anteriorly rectangular, caudally tapering to an obtuse point; posterior margin with convex apex, laterally concave; tergite surface smooth; posterolateral processes minute, less than 0.10 Plt length, straight, tapering to an acute tip, orientated posteriorly; width at posterolateral processes 0.50 Plt width.

A 1 (Fig. 23 B) length 0.28 body length; flagellum with 3 art. A 2 (Fig. 23 A) broken in the holotype, lacking the A 2 art beyond art 5. Adult male paratype ( SMF 56301, body length 1.6 mm, same as holotype) with A 2 length 0.44 body length; art 3 length subsimilar width, dorsal projection hook-shaped, orientated posteriorly and dorsally, apically and anteriorly serrated, subapically with single seta, length 0.78 art 3 length; art 6 with two short, acute distal projections, length 0.21 art 6 length; flagellum with 11 art.

Md (Fig. 24 B and C) incisors with five cusps each, left Md lacinia mobilis with 3 cusps. Mxp (Fig. 24 A) with 3 coupling hooks.

P 1 (Fig. 23 E) propodus dorsal margin smooth, with multiple groups of short setae and solitary elongated setae; P 2 length 0.51 body length; P 3 length 0.55 body length; P 4 length 0.56 body length; P 7 length 0.68 body length; P lengths gradually increasing posteriorly.

Plp 1 (Fig. 24 H) proximal half subrectangular, distal half projecting caudolaterally; lateral lobes indistinct, fused with medial lobes; medial lobes triangular, separated at apex by narrow gap. Plp 2 (Fig. 24 I) protopod semi-circular, distal margin with continuous row of simple setae, lateral margin with 1–3 short simple setae; endopod stylet distinctly longer than protopod. Plp 4 (Fig. 24 G) exopod length 0.76 endopod length. Urp (Fig. 21 A, C and Fig. 22 A) cylindrical, short, projecting caudally as far as posterior Plt apex; socket position recessed in sternal fold laterally to anal valve.

Description of the adult female paratype ( SMF 56477; where different from male)

Body (Fig. 21 B and Fig. 22 B) length 1.6 mm, 2.3 body width. Anterior and posterior body subsimilar in length. Ceph (Fig. 21 B and Fig. 22 B) length 0.49 width, 0.16 body length, width 0.76 body width; frontal margin width 0.45 Ceph width. Prn 4 lateral margin length 0.61 Prn 5 lateral margin length. Plt length 0.32 body length; width at posterolateral processes 0.45 Plt width.

A 1 length 0.25 body length. A 2 length 0.42 body length; art 3 dorsal projection length 0.60 art 3 length; flagellum with 10 art. P 1 length 0.48 body length, P 5 length 0.58 body length. Op length 0.59 Plt length; shape broad-oval, wider than long, surface smooth; distal and lateral margins with numerous, evenly distributed simple setae.

Diagnosis

Similar to Mastigoniscus latus ( Birstein, 1971) , but differing in the following characters: body size up to 1.6 mm (2.1–2.2 mm in M. latus ), dorsoventrally elliptical (dorsomedially vaulted, laterally flattened). Pleotelson anteriorly rectangular, caudally tapering to obtuse point (rounded). Antenna 2 article 3 dorsal projection curved (straight); article 6 with two short, acute distal projections (without distal projections).

Molecular Diagnosis: This species can be distinguished from Mastigoniscus latus ( Birstein, 1971) , the sole other congeneric species in the KKT region, on the basis of the following combination of mtDNA 16 S rRNA gene nucleotide substitutions: G (31), C (35), T (52), C (60), C (62), G (66), G (67), A (68), C (81), G (98), A (102), T (104), A (107), G (108), G (109), G (110), G (140), C (142), G (144), C (145), G (146), C (147), G (151), A (152), A (153), G (154), A (156), G (157), G (163), A (164), C (168), G (178), C (181), C (185), G (191), T (207), C (214), A (220), G (223), A (226), A (229), A (234), G (235), C (241), A (246), C (247), A (249), T (259), T (260), T (268), T (273) and G (448). The following combination of mtDNA COI rRNA gene nucleotide substitutions allow for further distinction: A (85), A (136), A (148), A (169), A (172), A (173), A (181), A (211), A (244), C (106), C (109), C (115), C (118), C (121), C (157), C (160), C (175), C (181), C (184), C (211), C (253), C (304), C (328), C (337), C (340), C (358), C (376), C (379), C (388), C (412), C (424), C (433), C (436), C (457), C (463), C (472), G (241), G (280), G (283), G (184), T (316), T (322), T (217) and T (238).

Etymology

The Latin adjective minimus (" smallest ") refers to the small body size of this species in comparison to its known congeners.

Distribution

Northwest Pacific Ocean, Kuril-Kamchatka Trench and adjacent abyssal regions to the southeast, 5136 – 7081 m.

Taxon discussion

Mastigoniscus minimus Wenz, Knauber & Riehl , sp. nov. represents the third species known of this genus from the Northwest Pacific, alongside M. microcephalus (Gamó, 1989) and M. latus ( Birstein, 1971) . Mastigoniscus minimus reportedly occurs in sympatry with M. latus in the Kuril-Kamchatka Trench. All three of these Northwest Pacific species have a broad and relatively short habitus with a broadly rounded pleotelson and small posterolateral processes in common. Their shared morphology and geographical distribution set them apart from the remaining species in the genus, indicating a sub-group within the genus. With body lengths of up to 1.6 mm, M. minimus Wenz, Knauber & Riehl , sp. nov. represents the smallest Mastigoniscus species known yet, as adult specimens of most species usually reach body lengths beyond 2 mm.

When comparing Mastigoniscus minimus Wenz, Knauber & Riehl , sp. nov. to the original description and new material of Mastigoniscus latus ( Birstein, 1971) , it became evident that the specimen depicted in the original description represents an adult male, but not the terminal male stage. However, a terminal male specimen ( SMF 56420) was present amongst our newly-collected material (see Knauber et al. (2022)). It differs from the specimen depicted by Birstein (1971) – amongst other characters – in a wider, less trapezoidal shape of the cephalothorax, the posterolateral pleotelson processes less protruding and the distal half of the first pleopods resembling the habitus of other known congeners. A thorough re-description of Mastigoniscus latus seems therefore necessary.

Notes

Methods

This study is based on collection material and molecular sequence information that has been previously published elsewhere (see Knauber et al. (2022) for details). Specimens are deposited at the Senckenberg Museum in Frankfurt, Germany. Associated (meta-) data are stored in the Barcode of Life Data System ( BOLD System, Ratnasingham and Hebert (2007)) available at https://doi.org/10.5883/DS-NWPHA22, GenBank ( Benson et al. 2012) accession numbers OM 782626 to OM 782641 ; Ocean Biogeographic Information System ( OBIS, Grassle 2000) available at https://ipt.iobis.org/obis-deepsea/resource?r=deep-sea_haploniscid_isopods; and Zenodo ( European Organization For Nuclear Research and OpenAIRE 2013) available at https://doi.org/10.5281/zenodo.6553796.

Material was collected during the KuramBio II (Kuril Kamchatka Biodiversity Studies II, Brandt (2016)) campaign on board RV Sonne to the Northwest Pacific Ocean. Box corer (BC; Hessler and Jumars (1974)), Agassiz trawl ( AGT; Agassiz (1880)) and epibenthic sledge ( EBS; Brenke (2005), Brandt et al. (2013)) were used. Samples were processed on board following Riehl et al. (2014 b).

Using a Leica M 60 stereomicroscope, an adult male was selected as holotype and an adult female as paratype following recent examples ( Brökeland and Raupach 2008, Brökeland 2010, Brökeland and Svavarsson 2017). For drawings, a Leica DM 2500 LED with camera lucida was used. Damage-free transfer of specimens from ethanol to glycerine followed Knauber et al. (2022). Temporary slides were prepared following Wilson (2008). Pencil drawings were digitally traced with Adobe Illustrator 27.2 ( Coleman 2003).

While in glycerine, specimens were stained using Congo Red dissolved in 70 % denatured EtOH following Michels and Büntzow (2010) for Confocal Laser Scanning Microscopy ( CLSM) using a Leica DM 2500 with a Leica TCS SPE II and LEICA LAS X 3.5. 5.19976. Post-production of CLSM-scans was carried out in Adobe Photoshop 24.1. 1 and Adobe Illustrator 27.2. Measurements followed the standards of Hessler (1970).

In the description, all appendages’ article-length ratios are given in proximal to distal order, excluding setae. Many ratios are used for descriptions in this paper. To avoid multiple repetition of the word ‘ times, ’ these are reported as a multiplier of an object of a telegraphic phrase to indicate the size of the subject of the phrase. For example, ‘ endopod length 2.2 width’ means ‘ the length of the endopod is 2.2 times its width. ’ This example is mathematically equivalent to the equation ‘ L = 2.2 W’. Dependent object clauses, separated off by a comma, do not repeat the subject. Descriptions of pereopod setae are provided in proximal to distal and lateral to medial order of description.

Morphological terminology was based on Brökeland and Svavarsson (2017) with modifications. Setae were named after Riehl and Brandt (2010). The molecular diagnosis was prepared using the online-tool DeSigNate ( Hütter et al. 2020), only focusing on base positions with a discriminative power of 1.0.

Figures

Figure 21. Mastigoniscus minimus Wenz, Knauber & Riehl, sp. nov. A. Male holotype SMF 56475, cLSM images of habitus, dorsal view; B. Female paratype SMF 56477, habitus, dorsal view; C. Male holotype SMF 56475, pleotelson, ventral view; D. Female paratype SMF 56477, pleotelson, ventral view. Scale bar: 0.2 mm.

Figure 22. Mastigoniscus minimus Wenz, Knauber & Riehl, sp. nov. A. Male holotype SMF 56475, habitus, dorsal view; B. Female paratype SMF 56477, habitus, dorsal view. Scale bar: 0.5 mm.

Figure 23. Mastigoniscus minimus Wenz, Knauber & Riehl, sp. nov. Male paratype SMF 56301. A. Antenna 2, lateral view. Male holotype SMF 56475; B. Antenna 1, lateral view; C. Pereopod 7; D. Pereopod 2. Female paratype SMF 56477; E. Pereopod 1. Scale bars: 0.2 mm.

Figure 24. Mastigoniscus minimus Wenz, Knauber & Riehl, sp. nov. cLSM images of male holotype SMF 56475. A. Maxilliped; B. Left mandible; C. Right mandible; D. Maxilla 1; E. Maxilla 2; F. Pleopod 3; G. Pleopod 4; H. Pleopod 1; I. Pleopod 2. Female paratype SMF 56477. J. Operculum. Scale bars: 0.2 mm.