TABLE 2 in A new species of Eurythenes (Crustacea: Amphipoda) from abyssal depths in the Peru-Chile Trench.

TABLE 2. Morphological species matrix of the genus Eurythenes. Derived from the matrix table produced in Havermans et al. (2013) to include all Eurythenes species currently described and further adapted to include key characteristics identified by D’Udekem d’ A coz & Havermans (2015). Features presented in bold are key to the identification of Eurythenes inti sp. nov. Species included are Eurythenes inti sp. nov. (this study); Eurythenes aequilatus Narahara-Nakano, Nakano & Tomikawa, 2017; Eurythenes andhakarae D’Udekem d’Acoz & Havermans, 2015, *Eg2; Eurythenes atacamensis Weston & Espinosa-Leal in Weston, Espinosa-Leal, Wainwright, Stewart, González, Linley, Reid, Hidalgo, Oliva, Ulloa, Wenzhöfer, Glud, Escribano & Jamieson, 2021, Eurythenes gryllus (Lichtenstein in Mandt, 1822) *Eg1; Eurythenes magellanicus (H. Milne Edwards, 1848), *Eg4+5, Eurythenes maldoror D’Udekem d’Acoz & Havermans, 2015 *Eg3, Eurythenes obesus (Chevreux, 1905), Eurythenes plasticus Weston in Weston, Carrillobarragan, Linley, Reid & Jamieson, 2020, Eurythenes sigmiferus D’Udekem d’Acoz & Havermans, 2015, *Eg6, Eurythenes thurstoni Stoddart & Lowry, 2004. *Eg represents the morphospecies designation in Havermans et al. (2013). Eurythenes inti sp. nov. (This Study)Eurythenes aequilatusEurythenes andhakaraeEurythenes atacamensisEurythenes gryllusEurythenes magellanicusEurythenes maldororEurythenes obesusEurythenes plasticusEurythenes sigmiferusEurythenes thurstoniType localityPeru-Chile Trench, Eastern South PacificSea of Okhotsk, West of Shiretoko Peninsula, Hokkaido, Japan, Pacific OceanEast of Antarctic Peninsula, Weddell Sea, Southern OceanAtacama Trench, Eastern South Pacific OceanGreenland SeaCape Horn, Drake Passage, Southern OceanArgentine Basin, South Pacific OceanHolotype: Azores, in the eastern North Atlantic Ocean. Neotype: Northeast of Cape Verde Islands, eastern North AtlanticMariana Trench, Pacific OceanBrazil Basin, Southwestern Atlantic OceanAustralia, Tasman Sea, Southeast of Twofold Bay, Southwest Pacific OceanKnown geographic rangeNorthern Peru-Chile Trench (Milne-Edwards), Southeast PacificSea of Okhotsk, Northwest PacificSouthern Ocean; South AtlanticAtacama Trench, South PacificNorwegian Sea; Greenland Sea, Arctic Ocean; Weddell Sea, Southern OceanBrazil abyssal basin, Southwest Atlantic; Peru–Chile Trench, East Pacific; South China Sea, West Pacific; Philippine SeaWeddell Sea; Argentinian basin, North Atlantic; North Pacific; East Indian Ocean; Central PacificNorth Atlantic; South Atlantic; South Pacific; Southern OceanPacific OceanGulf of Mexico, Southwest Pacific; South AtlanticSouthwest Pacific; East Indian; North Atlantic; Gulf of Mexico; Caribbean SeaKnown depth range (m)4602 - 61731574 - 15823070 - 70994974 - 8081839 - 55501342-48463070 - 6546128 - 41093982 - 69493410-6097128- 1960Pereon and Pleosome: segments with distinct dorsal sigmoid profilePleonite 3Pleonite 3Pleonite 3Pleonite 3Pleonite 3Pleonite 3Pleonite 3Pleonites 1-3Pleonites 1-3Pereonites 6+7 and pleonites 1-3Pleonite 1Head: anterior lobe developmentStrongly producedWeakly producedStrongly producedWeakly producedWeakly producedStrongly producedStrongly producedWeakly producedStrongly producedStrongly producedWeakly producedEye: shape of ventral cornerBlunt, pointing obliquely downwardsAcute and pointing linearly downwardsBlunt and pointing obliquely downwardsBlunt and pointing obliquely downwardsAcute and pointing linearly downwardsBlunt and pointing obliquely downwardsBlunt and pointing obliquely downwardsAcute and pointing linearly downwardsAcute and pointing linearly downwardsBlunt and pointing obliquely downwardsN/AMandible palp: article 2 width and shapeNarrowBroadNarrowBroadNarrowNarrowBroadNarrowNarrowNarrowBroadInner plate of maxilliped: number and degree of protrusion of anterior nodular spines3, not protruding3, protruding3, not protruding3, not protruding3-4, not protruding3-6, protruding8-9, not protruding3, protruding3-4, protruding9-10, protruding4, protrudingGnathopod 1 basis: ratio length/widthNarrow, 3.0x as long as wideBroad, 2.1 x as long as wideBroad, 2.3 - 3.0 x as long as wideBroad, 2.2 x as long as wideBroad, 2.5x as long as wideBroad, 2.5x as long as wideNarrow, 3.3 x as long as wideBroad, 2-2.5x as long as wideBroad, 2.9 x as long as wideBroad, 2.9 x as long as wideNarrow, 3.6 x as long as wideGnathopod 1 palm: degree of protrusionWell producedScarcely producedScarcely producedShort, scarcely producedNone to scarcelyNoneSlightly but distinctly producedSlightly convexNot protruding, weakly convexWeakly producedWeakly producedCoxa 2: ventral border shapeWeakly curvedWeakly curvedWeakly curvedWeakly curvedWeakly curvedWeakly curvedStrongly curvedWeakly curvedWeakly curvedWeakly curvedWeakly curvedGnathopod 2 propodus: proportionsFairly long, fairly broadLong, narrowFairly short, fairly narrowLong, narrowLong, narrowShort, broadLong, narrowLong, narrowShort, broadVery short, very broadLong, narrowGnathopod 2 palm: shape and curvatureConvexSlightly obtuse, curvedSlight curvedStrongly oblique and oriented outwardsStrongly oblique and oriented outwardsOblique and oriented inwardsSlightly curved and transverseTransverse, convexWeakly curved, palm convexDistinctly curved and intrusively obliqueObtuse, convexGnathopod 2 palm: number of spines3 spines3 spines2-5 spines2 spines2 stout spines4 spines2 spines2 spines3 spines4 spines3 spinesCoxal plate 4: widthBroadBroadFairly broadBroadBroadVariableNarrowBroadBroadFairly narrowBroadCoxal plate 4: anteroventral angleBluntly angularBluntly angularBluntly angularBluntly angularBluntly angularBluntly angularRoundedBluntly angularBluntly angularRoundedBluntly angularPereopod 7 basis: degree of posterior lobe expansionStrongly expandedStrongly expandedStrongly expandedModerately expandedStrongly expandedStrongly expandedModerately expandedModerately expandedStrongly expandedStrongly expandedModerately expandedPereopod 7 basis: distal lobe shapeModerately protrudingModerately protrudingModerately protrudingModerately protrudingModerately protrudingModerately protrudingStrongly protrudingModerately protrudingWeakly protrudingModerately protrudingStrongly protrudingPereopod 5-7 basis: posterior border crenulationWeakWeak to very weakStrongStrongMedium to strongMedium to strongWeak to very weakWeakStrongStrongWeakPereopod 5-7 merus: degree of broadeningBroadStrongNarrowBroadBroadBroadBroadModerateStrongBroadBroadEpimeral plate 3: tooth (in specimens ≥ 35 mm)AbsentAbsentPresentPresentAbsentPresent or absentAbsentAbsentAbsentAbsentAbsentEpimeral plate 3: profile of ventral marginWeakly curvedWeakly curved to nearly straightStrongly curvedStrongly curvedStrongly curvedWeakly to strongly curvedWeakly curved to nearly straightWeakly curvedWeakly curvedWeakly curvedWeakly curved ......continued on the next page ......continued on the next page ......continued on the next page