taxonID	type	description	language	source
0397030EFFD4E27FFC8EFA63FB78FED0.taxon	description	Multi-gene analyses of the calanoid superfamilies have been made to investigate the relationships within the Calanoida (Blanco-Bercial et al., 2011; Bradford-Grieve et al., 2014) by using both mitochondrial and nuclear ribosomal gene regions. These analyses demonstrated a high support of the morphology-based phylogeny by Andronov (1974) with its amendments made by Bowman & Abele (1982) and Park (1986). These molecular-based phylogenetic studies did not, however, include representatives of the superfamilies Ryocalanoidea and Epacteriscidae, and refinements in the currently available phylogeny are expected when new data are added. The discovery of two new species of ryocalanid copepods in the Kurile-Kamchatka trench belonging to the genera Ryocalanus Tanaka, 1956 and Yrocalanus Renz, Markhaseva & Schulz, 2012 and the description of the previously unknown female of Ryocalanus infelix, the type species of the Ryocalanidae, presented an opportunity to combine morphological and molecular data to further our knowledge on the phylogeny of the Calanoida. Our morphological studies were complemented with molecular analyses of ryocalanoidean and spinocalanoidean copepod species using multi-gene approaches to gain insight into the relationship between the evolutionarily youngest calanoid copepod families from a molecular perspective. The phylogeny of the Ryocalanoidea is discussed, based on a combined morphological and molecular approach.	en	Renz, Jasmin, Markhaseva, Elena L., Laakmann, Silke (2018): The phylogeny of Ryocalanoidea (Copepoda, Calanoida) based on morphology and a multi-gene analysis with a description of new ryocalanoidean species. Zoological Journal of the Linnean Society 185: 925-957
0397030EFFD1E272FEAFFD54FDEEFB86.taxon	description	(FIGS 1 – 5) Type material Holotype: Adult female, dissected, body length 2.17 mm, collection number SMF 37149 / 1 – 6 (one vial, five slides); Kurile-Kamchatka trench, 40.5808 ° N, 150.9833 ° E, station 9 – 9, project KuramBio, 23 August 2012, above the sea bed at a depth of 5400 m. Paratypes: One adult female. Body length 2.05 mm, collection number SMF 37150 / 1 – 5 (one vial, four slides); Kurile-Kamchatka trench, 43.0303 ° N, 152.9758 ° E, station 7 – 10, project KuramBio, 17 August 2012, above the sea bed at a depth of 5304 m. One adult male, body damaged, length 1.83 mm, collection number SMF 37151 / 1 – 6 (one vial, five slides); Kurile-Kamchatka trench, 41.2000 ° N, 150.0833 ° E, station 10 – 12, project KuramBio, 28 August 2012, above the sea bed at a depth of 5251 m. Etymology: The specific name refers to the scale-like structures that cover the antennule. Description: Based on female holotype unless stated otherwise. Adult female: Total length 2.17 mm; prosome 4.8 times as long as urosome (Fig. 1 A, B). Rostrum (Fig. 1 C) stout and strong, one-pointed. Cephalosome and pediger 1 partly fused (Fig. 1 A), pedigers 4 – 5 separate; in lateral view, posterolateral corners of prosome extended posteriorly into points, reaching to middle of genital double-somite (Fig. 1 A, B). Pedigers 2 – 5 covered with fine spinules. Urosome composed of genital double-somite and three articulated somites (Fig. 1 A, B, D – H). Genital double-somite slightly asymmetrical, with lateral swelling on left side and ventromedial genital opening; in lateral view genital double-somite swollen ventroanteriorly, seminal receptacles of oval shape. Genital double-somite and urosomites covered with rows of fine spinules (Fig. 1 A, B, D – H). Caudal rami symmetrical with two lateral setae (II and III), three terminal setae (IV – VI) and one dorsal seta (VII). Antennule (Fig. 1 I, K) of 24 free segments and extending to pediger 2, covered with scale-like structures. In holotype armature as follows: I – 2 s + 1 ae?, II – IV – 5 s + 2 ae?, V – 2 s + 1 ae, VI – 2 s + 1 ae, VII – 2 s + 1 ae, VIII – 2 s + 1 ae, IX – 2 s + 1 ae; X – XI – 4 s + 1 ae, XII – 1 s + 1 ae, XIII – 2 s, XIV – 2 s + 1 ae, XV – 1 s, XVI – 2 s + 1 ae, XVII – 2 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s + 1 ae, XX – 2 s, XXI – 2 s + 1 ae, XXII – 1 s, XXIII – 1 s, XXIV – 2 s, XXV – 2 s, XXVI – 2 s, XXVII – XXVIII – 5 s + 1 ae. Antenna (Fig. 2 A), coxa with 1, basis with 2 setae; endopod segment 1 with 2 setae, segment 2 with 16 setae; exopod incompletely 8 - segmented, with 1, 3, 1, 1, 1, 1, 1, 3 setae. Mandible (Fig. 2 B – D), gnathobase cutting edge with 7 unequal teeth plus ventral seta; exopodal segments with 6 setae; first endopod segment with 2 setae, second with 11 setae; basis with 2 setae. Exopod to endopod ratio 0.82. Maxillule (Fig. 2 E, F), praecoxal arthrite with 9 terminal spines (Fig. 2 F), 4 posterior and 2 anterior setae; coxal endite with 6 setae, coxal epipodite with 9 setae; proximal basal endite with 4 setae, distal basal endite with 5 setae; endopod with 15 setae; exopod with 11 setae. Maxilla (Fig. 2 G, H), proximal praecoxal endite bearing 4 setae plus attenuation in holotype, 5 setae plus attenuation in paratype, distal praecoxal endite with 3 setae; coxa without outer seta; coxal endites with 3 setae each; proximal basal endite with 4 setae; endites 2 – 5 with surface spinules, remaining endopod with 8 setae. Maxilliped (Fig. 2 I), syncoxa with 1 seta on praecoxal endite, 2 setae on proximal coxal endite, 3 setae on middle coxal endite, and 3 setae on distal coxal endite; syncoxa with fine rows of spinules. Basis with 3 distal setae; endopod 6 - segmented with 2, 4, 4, 3, 3 and 4 setae. Legs 1 – 4 biramous (Fig. 3 A – E). Exopods and endopods 3 - segmented, except leg 1 endopod 1 - segmented and leg 2 endopod 2 - segmented. Anterior and posterior surface of legs covered with spinules, these spinules much smaller on anterior surface. Coxa of all legs with surface spinules on inner margin; terminal spines on exopod segment 3 finely serrated. Seta and spine formula as in Table 3. Leg 1 (Fig. 3 A), endopod lateral lobe with spinules. Leg 4 (Fig. 3 D), coxa with medial seta (broken in holotype); basis with row of spinules on distal margin; left leg abnormal in holotype (Fig. 3 E), lacking lateral spines on exopod segment 1 and 3 (no scars), and terminal spine on exopod 3, smaller as right leg. Adult male: Total length 1.83 mm, prosome 4.6 times as long as urosome (Fig. 4 A, B). Rostrum (Fig. 4 A, C) stout, strong and one-pointed. Cephalosome and pediger 1 separate (Fig. 4 A, B), pedigers 4 and 5 separate. In lateral view, right posterolateral corner of prosome extended posteriorly into points slightly exceeding urosomite 1 (Fig. 4 D). Pedigers 2 – 5 covered with fine spinules. Caudal rami (Fig. 4 B, E) slightly asymmetrical, with one lateral seta (III?), three terminal setae (IV – VI) plus one dorsal seta (VII). Left antennule (Fig. 4 F) unmodified, of 24 free segments, extending to pediger 2, covered with scale-like structures; armature as follows: I – 1 s + 1 ae, II – IV – 5 s + 4 ae?, V – 2 s + 1 ae, VI – 2 s + 1 ae, VII – 2 s + 2 ae, VIII – 1 s? + 2 ae, IX – 2 s + 2 ae, X – XI – 4 s + 4 ae, XII – 1 s + 1 ae; XIII – 2 s + 1 ae; XIV – 2 s + 1 ae, XV – 2 s + 1 ae, XVI – 2 s + 1 ae, XVII – 2 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s + 1 ae, XX – 2 s + 1 ae, XXI – 2 s + 1 ae, XXII – 1 s + 1 ae, XXIII – 1 s + 1 ae, XXIV – 2 s + 1 ae, XXV – 2 s + 1 ae, XXVI – 2 s, XXVII – XXVIII – 4 s + 1 ae. Right antennule (Fig. 5 A – D) strongly modified for grasping, of 23 free segments; segments XX to XXVI wider than on the left; segments XX to XXII – XXIII with surface spinules; segments XX and XXI with 1 proximal spine each, segment XXV and XXVI with strong lateral attenuations proximally, segment XXII – XXIII fused; hinges occurring between segments XIX and XX, XX and XXI, and XXII – XXIII and XXIV. Armature as follows: segment I – 2 s + 1 ae, II – IV – 6 s + 2 ae?, V – 2 s + 2 ae, VI – 1 s + 2 ae, VII – 2 s + 2 ae, VIII – 2 s + 2 ae, IX – 2 s + 2 ae; X – XI – 4 s + 3 ae, XII – 1 s + 1 ae, XIII – 2 s + 1 ae, XIV – 2 s + 1 ae, XV – 1 s + 1 ae, XVI – 2 s + 1 ae, XVII – 2 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s + 1 ae, XX – 1 s + 1 ae + spine, XXI – 1 s + 1 ae + spine, XXII – XXIII – 2 s + 1 ae, XXIV – 2 s, XXV – 2 s + 1 ae + strong, attenuation, XXVI – 2 s + strong, spine like attenuation, XXVII – XXVIII – 5 s + 1 ae. Antenna, mandible and maxillule similar to those of female. Maxilla as in female, with proximal praecoxal endite bearing 4 or 5 setae, but without attenuation. Maxilliped similar to that of female. Legs 1 – 4 similar to those of female, but less spinulose. Leg 2 one leg abnormal, lacking lateral spines on exopod segment 1 and 2 (no scars), and terminal spine on exopod 3, exopod 3 with 7 setae, leg small. Leg 4 coxa without strong spinules (Fig. 5 E). Leg 5 (Fig. 5 F) uniramous on both sides, covered with rows of spinules on posterior surface. Right leg with 1 - segmented exopod, shorter than left leg, with terminal spine. Left leg with 3 - segmented exopod, terminal segment with two spines. R e m a rk s: T h e n e w s p e c i e s s h a r e s t h e m a i n morphological characters with species of the genus Ryocalanus (Renz et al., 2013), which is a 1 - pointed rostrum, the armament of the female antennule ancestral segment XXII with 1 seta, a leg 1 endopod with a proximal inner wedge-shaped projection and a male antennule with ancestral segments XXI / XXII – XXIII fused. Both sexes are known only for R. brasilianus Renz, Markhaseva & Schulz, 2013, while R. spinifrons Shimode, Toda & Kikuchi, 2000 is only known from females and R. bowmani Markhaseva & Ferrari, 1996 and R. infelix Tanaka, 1956 are represented only by males (female of R. infelix is described herein). Ryocalanus squamatus sp. nov. differs from all other Ryocalanus species by the shape of the rostrum, which is short and stout, compared to the long and slender rostrum possessed by all other Ryocalanus species and an only slightly asymmetrical genital segment, which is strongly asymmetrical in R. brasilianus, R. spinifrons and R. infelix. Pedigers 2 – 5, as well as the anterior part of the legs, are covered in fine spinules, which are absent in other Ryocalanus females, and the coxa of leg 4 lacks the robust spines that are usually found in all other ryocalanid females of the genera Ryocalanus and Yrocalanus. The antennule is covered with scale-like structures, a character not detected so far in any other species of Ryocalanus. There are significant morphological transformations in the Ryocalanus male right ancestral antennule segments distal to segment XIX, and evidence that ancestral segments XXI / XXII – XXIII are fused, with the main hinge located between fused segments XXII – XXIII and segment XXIV. This is unlike the earlier interpretation of the R. infelix male right antennule (Ohtsuka & Huys, 2001). Consequently, the male right antennules of Ryocalanus species are distinct to the male right antennules in the genus Yrocalanus, where the main hinge can be found between segment XXII and fused segments XXIII – XXIV. For further comments, see also remarks for the description of a R. infelix female with additional comments for the male. The right male antennule of Ryocalanus squamatus sp. nov. differs from that of other Ryocalanus males in the shape of segment XXV, which has a strong lateral attenuation, being longer than the segment itself. This attenuation is absent in other Ryocalanus species. Furthermore, segments XX – XXIII are equipped with surface spinules in R. squamatus sp. nov., while present on segments XIX – XXIII in R. infelix (Tanaka, 1954) and segments XIV – XXI in R. brasilianus (Renz et al., 2013). These spinules are lacking in the R. bowmani male right antennule. The lateral teeth observed on the male antennule segments XXVI and XXIV in Ryocalanus infelix and R. brasilianus and the combed spines on segments XXIV and XXV in R. bowmani are absent in R. squamatus sp. nov .. The antenna exopod to endopod ratio in the new species is 0.82, while in all other Ryocalanus species it is close to 1, a character hypothesized to be diagnostic for the genus Ryocalanus (Renz et al., 2013). The mandible basis carries 2 setae (vs. 3 setae in all other Ryocalanus species), the mandible first endopod segment carries 2 setae (vs. 4 setae in all other Ryocalanus species) and the maxilliped endopod segment 5 outer seta is missing (this seta is present in all other species). Males of Ryocalanus squamatus sp. nov. differ from their congeers in the shape of the rostrum, the spinules covering pedigers 2 – 5 and the scale-like structures covering the antennule (the latter two not present in other Ryocalanus species), the shape of ancestral segments on the right antennule with a large, hook-like extension on the posterior border of ancestral segment XXV, and the number and morphology of spines and segments of leg 5. From the armature of the 2 - segmented right leg 5 it cannot be distinguished if the segments comprise a fused coxo- and basipodite with a one-segmented exopod or if the exopod is reduced. Some variability was observed in the armature of the proximal praecoxal endite of the maxilla between right and left limb of individuals in both female and male specimens, i. e. the presence of 4 or 5 setae. Furthermore, this endite was always equipped with a short attenuation in females, a feature not reported before in other ryocalanid species. However, a re-examination of the holotype of Yrocalanus bicornis (Markhaseva & Ferrari, 1996) (Smithsonian Institution, Catalogue No. USNM 264034, as Ryocalanus bicornis Markhaseva & Ferrari, 1996) showed that this short attenuation was present in the type material from Volcano 7. In both sexes of R. squamatus sp. nov., the distal spine on the maxillule praecoxal arthrite had a cavity at its tip, presumably a specific adaptation connected with feeding. This character was also found during the re-examination of the holotype of Ryocalanus bowmani from Volcano 7 (Smithsonian Institution, Catalogue No. USNM 268291; Fig. 6). A morphologically similar structure can be found in the mandible of Heterorhabdidae, although it is not clear from the analysis by light microscopy if this structure serves the same function during predatory feeding as suggested for this family (Ohtsuka et al., 1997). Abnormalities were observed in the formation of a swimming leg of Ryocalanus squamatus sp. nov., as in one female, as well as the male specimen, exopods of leg 4 and 2, respectively, lacked lateral spines, and exopod segment 3 lacked the terminal spine and deviated in the setation typical for this taxon.	en	Renz, Jasmin, Markhaseva, Elena L., Laakmann, Silke (2018): The phylogeny of Ryocalanoidea (Copepoda, Calanoida) based on morphology and a multi-gene analysis with a description of new ryocalanoidean species. Zoological Journal of the Linnean Society 185: 925-957
0397030EFFD8E26CFF52FBE5FDA6FDE0.taxon	description	(FIGS 7 – 10) Material: Adult female, dissected, body length 2.65 mm, collection number SMF 37152 / 1 – 6 (one vial, five slides); Kurile-Kamchatka trench, 46.2333 ° N, 155.5333 ° E, station 2 – 10, project KuramBio, 3 August 2012, above the sea bed at a depth of 4865 m. One adult female, dissected, body length 2.60 mm, collection number SMF 37153 / 1 – 4 (one vial, three slides); Kurile-Kamchatka trench, 43.0166 ° N, 152.9666 ° E, station 7 – 10, project KuramBio, 17 August 2012, above the sea bed at a depth of 5223 m. One adult male, dissected, body length 2.11 mm, collection number SMF 37154 / 1 – 4 (one vial, three slides); Kurile-Kamchatka trench, 43.5666 ° N, 153.9666 ° E, station 5 – 10, project KuramBio, 11 August 2012, above the sea bed at a depth of 5375 m. One adult male, dissected, body length 2.11 mm, collection number SMF 37155 / 1 – 3 (one vial, two slides); Kurile-Kamchatka trench, 46.2333 ° N, 155.5333 ° E, station 2 – 10, project KuramBio, 3 August 2012, above the sea bed at a depth of 4865 m. Description: Based on two females and two males. Adult female: Total length 2.65 mm; prosome 5.1 times as long as urosome (Fig. 7 A, B). Rostrum (Fig. 7 A, C) one-pointed, slender. Cephalosome and pediger 1 separate (Fig. 7 A, B), pedigers 4 – 5 separate; in dorsal view posterolateral corners of prosome asymmetrical, extended posteriorly into points, extending to distal margin of genital double-somite on right side and to distal margin of second urosomal segment on left side (Fig. 7 A, B, D). Ventral inner surface of pediger 5 with short spinules. Urosome composed of genital double-somite and three articulated or partly articulated somites (Fig. 7 D – G). Genital double-somite asymmetrical, with lateral swelling on right side or left side and faint line of incomplete fusion on dorsal and ventral surface; in lateral view swollen ventromedially, seminal receptacles in lateral view oval, turned upward. Urosomites 2, 3 and 4 asymmetrical, 3 and 4 partly fused. Urosome covered by viscous mass. Caudal rami asymmetrical with right ramus longer and wider than left; both rami with row of spinules on inner margin and with two lateral setae (II and III), three terminal setae (IV – VI) and one dorsal seta (VII). Antennule (Fig. 7 H) of 24 free segments, armature as follows: I – 1 s + 1 ae, II – IV – 6 s + 4 ae, V – 2 s + 2 ae, VI – 2 s + 1 ae, VII – 2 s + 2 ae, VIII – 2 s + 2 ae, IX – 2 s + 2 ae; X – XI – 4 s + 4 ae, XII – 1 s, XIII – 2 s + 2 ae; XIV – 2 s, XV – 1 s + 1 ae, XVI – 2 s + 1 ae, XVII – 2 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s, XX – 2 s + 1 ae, XXI – 2 s, XXII – 1 s, XXIII – 1 s, XXIV – 2 s, XXV – 2 s, XXVI – 2 s, XXVII – XXVIII – 4 s + 1 ae. Antenna (Fig. 8 A), coxa with 1, basis with 2 setae; endopod segment 1 with 2 setae and row of spinules, segment 2 with 16 setae; exopod 8 - segmented, with 1, 3, 1, 1, 1, 1, 1, 3 setae. Mandible (Fig. 8 B), gnathobase cutting edge with 8 unequal teeth plus ventral seta; basis with 3 setae; exopodal segments incompletely fused, with 6 setae; first endopod segment with 4 setae (3 setae plus 1 scar), second with 11 setae. Maxillule (Fig. 8 C), praecoxal arthrite with 9 terminal spines, 3 posterior and 1 anterior setae; posterior surface of praecoxal arthrite with small spinules; coxal endite with 6 setae, coxal epipodite setae broken in all specimens; proximal basal endite with 4 setae, distal basal endite with 5 setae and small surface spinules; endopod with 12 setae and patch of small surface spinules; exopod with 8 setae. Maxilla (Fig. 8 D), proximal praecoxal endite bearing 3 setae plus attenuation on left limb, 5 setae in right limb, distal praecoxal endite with 3 setae and surface spinules; coxa with 1 outer seta; coxal endites with 3 setae each and surface spinules; proximal basal endite 4 setae; remainig endopod with 9 setae. Maxilliped (Fig. 9 A), syncoxa with 1 seta on proximal praecoxal endite, 2 setae on middle endite, and 3 setae on distal praecoxal endite; coxal endite with 3 setae; basis with 3 medial setae; endopod 6 - segmented with 2, 4, 4, 4, 3 + 1, and 4 setae. Legs 1 – 4 biramous (Fig. 9 B – E) with 3 - segmented exopods, endopod 1 - segmented in leg 1, 2 - segmented in leg 2 and 3 - segmented in legs 3 – 4. All endopod and exopod segments with rows of spinules on posterior surface. Coxa of legs 1 – 3 with inner surface spinules. Leg 2 and 3 with finely serrate terminal spine on exopod segment 3. Seta and spine formula as in Table 4. Leg 1 (Fig. 9 B), endopod lateral lobe with spinules and inner wedge-shaped projection; exopod segment 1 with lateral spine (broken in one specimen) and inner spinules, segment 2 with long lateral spine about the length of exopod segment 2 and 3 together, segment 3 with terminal spine, broken in one specimen. Leg 2 (Fig. 9 C), coxa with medial seta. Leg 4 (Fig. 9 E, F), coxa with inner surface spinules, 1 strong and 8 short distolateral spines, and patches of spinules on posterior surface. Adult male: Total length 2.11 mm (Fig. 10 A). Oral limbs and swimming legs as in original description by Tanaka (1956), deviating only in following details: Left antennule (Fig. 10 B) unmodified, of 24 free segments, extending to first urosome segment; armature as follows: I – 1 s + 1 ae, II – IV – 5 s + 3 ae? + 2 short sensillae (Fig. 10 B, see arrows), V – 2 s + 2 ae + 1 short sensilla, VI – 2 s + 1 ae, VII – 2 s + 2 ae + 1 short s in particular position, VIII – 2 s + 2 ae, IX – 2 s + 2 ae, X – XI – 4 s + 4 ae, XII – 1 s + 2 ae; XIII – 2 s + 2 ae; XIV – 2 s + 1 ae, XV – 1 s + 1 ae, XVI – 2 s + 1 ae, XVII – 1 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s + 1 ae, XX – 2 s + 1 ae, XXI – 2 s + 1 ae, XXII – 1 s + 1 ae, XXIII – 1 s + 1 ae, XXIV – 2 s + 1 ae, XXV – 2 s + 1 ae, XXVI – 2 s, XXVII – XXVIII – 4 s + 1 ae. Right antennule (Fig. 10 C – E) strongly modified for grasping, of 22 free segments; segments XVIII – XXII / XXIII with surface spinules; segments XIX – XXVI strongly enlarged; segments XX and XXI with 1 proximal spine each, segments XXI – XXII partly fused, segments XXII – XXIII fused, segment XXIV with lateral broad denticulated lamella, segment XXV with small lateral chitinized lamella; hinges occurring between segments XVIII and XIX, XIX and XX, XX and XXI, XXIII and XXIV, XXIV and XXV and XXIV and XXV. Armature as follows: segment I – 1 s + 1 ae, II – IV – 6 s + 4 ae, V – 2 s + 2 ae, VI – 2 s + 1 ae, VII – 2 s + 2 ae, VIII – 2 s + 2 ae, IX – 2 s + 1 ae; X – XI – 4 s + 3 ae, XII – 1 s + 2 ae, XIII – 2 s + 2 ae, XIV – 2 s + 1 ae, XV – 1 s + 1 ae, XVI – 2 s + 1 ae, XVII – 2 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s, XX – 1 s + 1 ae + 1 spine, XXI – 1 s + 1 spine, XXII – XXIII – 2 s + 1 ae, XXIV – 2 s + 1 ae, XXV – 2 s + 1 ae, XXVI – 2 s, XXVII – XXVIII – 5 s + 1 ae. Remarks: Ryocalanus infelix was so far only known from a male specimen. Together with female specimens, also males of this species were present in the samples. COI sequence analysis verified the assignment of females and males to the same species (see below). The urosome of all female specimens was covered by a viscous mass (as indicated in Fig. 7 A, B) that was only removable by placing the urosome into lactic acid for at least 24 h. We hypothesize that this viscous mass-like structure is either connected to the mating process or might be remnants of egg sacs. The antennule of one female did show a quadrithek arrangement of appendages with segments V, VII, VIII, IX and XIII bearing two small, slender aesthetascs in addition to two setae. While the doubling of aesthetascs is unusual in female calanoid copepods, it has previously been observed in a few genera within the Calanidae by Fleminger (1985). He postulated that quadrithek females derive from genotypic males in which the gonad develops as an ovary and suggested that environmental factors or internal factors affect the final, phenotypic sex. The morphology of the male specimens is mostly as in the original description of Tanaka (1956), except for: the basis of leg 1 carries 1 medial seta that is missing in the original description; the maxillule coxal endite carries 6 setae (vs. 5 setae in the original description); and the maxillary endopodite carries 9 setae (vs. 8 setae in the original description). The setation of the left male antennule, which was missing in the original description, is given here. Segmental fusions in the right male antennule are not absolutely unambiguous in Ryocalanus infelix and R. squamatus sp. nov. due to the significant Ryocalanus male morphological transformations in the ancestral antennule segments distal to the segment XXI. More specifically, a fusion of segment XXV – XXVI, observed for R. infelix (Tanaka, 1956), could not be observed here. Instead, based on the morphology of the male antennules of Ryocalanus squamatus sp. nov. and R. infelix from the Kurile-Kamchatka trench, ancestral segments XXII and XXIII are apparently fused. This compund segment (XXII – XXIII) is distally followed by segments that are each supplied by two setae (both distoanterior and distoposterior), which is a marker for the ancestral segments XXIV, XXV, XXVI and XXVII (e. g. Huys & Boxshall, 1991). This interpretation can also be applied to R. brasilianus (Renz et al., 2013), for which the earlier interpretation of antennule segmental fusions was left for discussion. The right antennule of R. infelix differs from other Ryocalanus species in the shape of the denticulated and chitinized lamella on segments XXIV and XXVI, which is of a different structure in R. brasilianus (Renz et al., 2013) and absent in R. squamatus sp. nov. and R. bowmani (Markhaseva & Ferrari, 1996). The length of males discovered from the Kurile-Kamchatka trench varied between 1.95 and 2.15 mm. Females and males differed in the number of setae in the mandible endopod segment 2 (10 in males, 11 in females), the maxilla basal distal endite setation (four in females, three in males) and the maxilliped endopod setation (endopod 6 - segmented with 2, 4, 4, 4, 3 + 1, and 4 setae in females, endopod 6 - segmented, with 2, 4, 3, 2, 2 + 1, and 4 setae in males). The maxilla praecoxal endite showed variations in setation between left and right limbs of both, female and male individuals with the armament being 3 setae plus attenuation or 5 setae.	en	Renz, Jasmin, Markhaseva, Elena L., Laakmann, Silke (2018): The phylogeny of Ryocalanoidea (Copepoda, Calanoida) based on morphology and a multi-gene analysis with a description of new ryocalanoidean species. Zoological Journal of the Linnean Society 185: 925-957
0397030EFFC6E267FF51FDE2FD65FAE4.taxon	description	(FIGS 11 – 14) Type material Holotype: Adult female, dissected, body length 1.75 mm, collection number SMF 37156 / 1 – 5 (one vial, four slides); Kurile-Kamchatka trench, 43.5666 ° N, 153.9666 ° E, station 5 – 10, project KuramBio, 11 August 2012, above the sea bed at a depth of 5376 m. Paratypes: One adult female, body length 1.75 mm, collection number SMF 37157 / 1 – 4 (one vial, three slides); Kurile-Kamchatka trench 42.2333 ° N, 151.7000 ° E, station 9 – 9, project KuramBio, 20 August 2012, above the sea bed at a depth of 5125 m. One adult male, body length 1.58 mm, collection number SMF 37158 / 1 – 6 (one vial, five slides); Kurile-Kamchatka trench, 46.2333 ° N, 155.5333 ° E, station 2 – 9, project KuramBio, 3 August 2012, above the sea bed at a depth of 4863 m. One adult male, body length 1.53 mm, collection number SMF 37159 / 1 – 5 (one vial, four slides); Kurile-Kamchatka trench, 46.9740 ° N, 157.3048 ° E, station 1 – 11, project KuramBio, 30 July 2012, above the sea bed at a depth of 5418 m. Etymology: The specific name is derived from the location of collection, the Kurile-Kamchatka trench. Description: Based on female holotype unless otherwise stated. Adult female: Total length 1.75 mm; prosome 4.6 times as long as urosome (Fig. 11 A, B). Rostrum (Fig. 11 A, C) two-pointed. Cephalosome and pediger 1 partly fused (Fig. 11 A, B), pedigers 4 – 5 separate; in lateral view posterolateral corners of prosome extended posteriorly into points, reaching distal margin of the genital double-somite. Urosome composed of genital double-somite and three articulated somites (Fig. 11 D, E). Genital double-somite symmetrical, with short spinules distolaterally on right side and ventromedial genital opening; in lateral view seminal receptacles elongated, turned upward. Dorsal posterior margins of genital double-somite to third urosomal somite each with row of spinules (Fig. 11 D). Caudal rami symmetrical, with row of spinules on inner margin and with two lateral setae (II and III), three terminal setae (IV – VI) and one dorsal seta (VII). Antennule (Fig. 11 F) of 24 free segments and extending to distal border of pediger 2. In holotype armature as follows: I – 2 s + 1 ae, II – IV – 4 s + 3?, V – 2 s + 1 ae, VI – 2 s, VII – 2 s + 1 ae, VIII – 2 s, IX – 2 s + 1 ae; X – XI – 4 s + 1 ae?, XII – 1 s + 1 ae, XIII – 2 s + 1 ae, XIV – 2 s + 1 ae, XV – 1 s + 1 ae, XVI – 2 s + 1 ae, XVII – 2 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s + 1 ae, XX – 2 s + 1 ae, XXI – 2 s + 1 ae, XXII – 0 s, XXIII – 1 s, XXIV – 2 s, XXV – 2 s, XXVI – 2 s, XXVII – XXVIII – 4 s + 1 ae. Antenna (Fig. 12 A), coxa with 1, basis with 2 setae; endopod segment 1 with 2 setae, segment 2 with 17 setae; exopod 8 - segmented, with 1, 3, 1, 1, 1, 1, 1, 3 setae. Mandible (Fig. 12 B, C), gnathobase cutting edge with 8 unequal teeth plus ventral seta; basis with 3 setae; exopodal segments incompletely fused, with 6 setae; first endopod segment with 2 setae, second with 10 setae. Maxillule (Fig. 12 D), praecoxal arthrite with 9 terminal spines, 4 posterior and 1 anterior setae; posterior and anterior surface of praecoxal arthrite with small spinules; coxal endite with 6 setae, coxal epipodite with 8 setae; proximal basal endite with 4 setae, distal basal endite with 5 setae; endopod with 14 setae; exopod with 11 setae. Maxilla (Fig. 12 E), proximal praecoxal endite bearing 3 setae plus attenuation in holotype, 4 setae plus attenuation in paratype, distal praecoxal endite with 3 setae; coxal endites with 3 setae each; coxa with 1 outer seta; proximal basal endite with 3 setae; remaining endopod with 8 setae. All endites except for praecoxal endite with surface spinules. Maxilliped (Fig. 13 A), syncoxa with 1 seta on proximal praecoxal endite, 2 setae on middle endite, and 3 setae on distal praecoxal endite; coxal endite with 3 setae; syncoxa with row of spinules. Basis with 3 distal setae; endopod with 2, 4, 4, 3, 3 + 1, and 4 setae and row of spinules at setae basis on segment 3 and 4. Legs 1 – 4 biramous (Fig. 13 B – E), with 3 - segmented exopods and 3 - segmented endopods, except leg 1 endopod 1 - segmented and leg 2 endopod 2 - segmented. Leg 1 – 4 coxa with inner surface spinules. Legs 2 – 4 endopod segments with rows of spinules on posterior surface. Terminal spine on exopod segment 3 finely serrated. Seta and spine formula as in Table 5. Leg 1 (Fig. 13 B), basis with medial and lateral spinules; endopod lateral lobe poorly developed with spinules; exopod segment 2 with long lateral spine extending to distal end of exopod 3, and medial spinules, segment 3 terminal spine ca. 2.2 times as long as exopod. Leg 3 (Fig. 13 D), exopod segments 1 and 2 with lateral spine (broken in segment 2 in paratype), segment 3 with three lateral spines (1 spine broken in paratype). Leg 4 (Fig. 13 E), coxa with 3 strong distolateral spines and patches of spinules on posterior surface; basis with row of spinules on distal margin. Adult male: Total length 1.53 and 1.58 mm (Fig. 14 A, B). Rostrum (Fig. 14 A, C) two-pointed. Cephalosome and pediger 1 almost completely fused (Fig. 14 A, B), pedigers 4 and 5 separate. In lateral view posterolateral corners of prosome extended posteriorly into points, slightly extending urosomite 1. Caudal rami (Fig. 14 D) symmetrical, with two lateral setae (II and III), three terminal setae (IV – VI) and one dorsal seta (VII) Left antennule (Fig. 14 E) unmodified, of 24 free segments, extending to urosome; armature as follows: I – 1 s + 1 ae, II – IV – 6 s + 4 ae, V – 2 s + 2 ae, VI – 2 s + 1 ae, VII – 2 s + 2 ae, VIII – 2 s + 1 ae, IX – 2 s + 2 ae, X – XI – 4 s + 3 ae?, XII – 1 s + 1 ae; XIII – 2 s + 1 ae; XIV – 2 s + 1 ae, XV – 1 s + 1 ae, XVI – 2 s + 1 ae, XVII – 2 s + 1 ae, XVIII – 2 s + 1 ae, XIX – 2 s + 1 ae, XX – 2 s + 1 ae, XXI – 2 s + 1 ae, XXII – 0 s XXIII – 1 s + 1 ae, XXIV – 2 s + 1 ae, XXV – 2 s + 1 ae, XXVI – 2 s, XXVII – XXVIII – 3 s + 1 ae. Right antennule (Fig. 14 F, G) strongly modified for grasping, of 24 free segments; segments XX – XXVI strongly enlarged; segment XX with 1 distal strong hook-like attenuation, segment XXI with a straight, strong, spine-like attenuation and a serrated strong spine, segments XXIII – XXIV with a large plate, segment XXVI with lateral lamella; hinges occurring between segments XVIII and XIX, XIX and XX, XX and XXI, and XXII and XXIII. Armature as follows: I – 1 s + 1 ae, II to III – 4 s + 3 ae, IV – 2 s + 1 ae, segments V-XI armature as in left antennule; XII – 1 s + 1 ae, XIII-XIX armature as in left antennule, XX – 1 s + 1 ae + spine like attenuation XXI – 1 s + 2 spine like attenuations, XXII – 1 s + 1 ae, XXIII – XXIV – 2 s + 1 ae + 1?, XXV – 2 s + 1 ae, XXVI – 2 s, XXVII-XVIII – 4 s + 1 ae. Antenna as in female, except endopod segment 2 with 16 setae. Mandible similar to that of female, except basis with 2 setae. Maxillule as in female, but exopod with 10 setae. Maxilla similar to that of female, but proximal praecoxal endite bearing 3 setae. Maxilliped as in female. Segmentation of legs 1 – 4 as in female. Coxa of leg 4 without strong distolateral spines. Endo- and exopods of leg 4 missing in paratypes. Leg 5 (Fig. 14 H) uniramous on both sides. Right leg 2 - segmented, with small terminal spine, shorter than left leg. Left leg with 3 - segmented exopod. Exopod segment 2 with row of spinules distally, exopod segment 3 with medial row of spinules. R e m a rk s: T h e n e w s p e c i e s s h a r e s t h e m a i n morphological characters with species of the genus Yrocalanus (Renz et al., 2013). Both sexes are so far only known for Y. antarcticus Renz, Markhaseva & Schulz, 2012, while Y. admirabilis Andronov, 1992 is only known from a male and Y. bicornis and Y. asymmetricus Markhaseva & Ferrari, 1996 only from female specimens. Females of Yrocalanus kurilensis sp. nov. are easily distinguished from the remaining species of this genus by the shape of the rostrum, which is wider at its tips than in other Yrocalanus species, the shape of the posterolateral corners of the prosome with narrowed points, which is not found in other Yrocalanus species, the form of the genital double-somite, which is symmetrical in Yrocalanus kurilensis sp. nov, but asymmetrical in Y. asymmetricus, Y. bicornis (Markhaseva & Ferrari, 1996) and Y. antarcticus (Renz et al., 2012) and the 3 robust spines on the coxa of P 4 (only 2 in other Yrocalanus females). At least two different types of setae could be observed on the antennule, with short, frayed setae occurring on segment V – VIII, XI, XIV – XVI, XVIII and XX – XXI. Males of Yrocalanus kurilensis sp. nov. differ from the remaining species of this genus in the shape of ancestral segments of the right antennule. Segment XXI is equipped with a serrated spine reaching the lower third of compound segment XXIII – XXIV, while it reaches the distal border of segment XXIII – XXIV in Y. antarcticus and the distal border of segment XXV in Y. admirabilis (Andronov, 1992). Fused segments XXIII – XXIV are equipped with a large plate spanning the whole segment in Yrocalanus kurilensis sp. nov. This plate spans only half of the segment in Y. antarcticus and has the form of a small bulge in Y. admirabilis. Furthemore, the elongated projection on segment XXVI in Y. antarcticus and Y. admirabilis is absent in Y. kurilensis sp. nov. Differences can also be observed in the number and morphology of the spines and segments of leg 5, which is uniramous in Y. kurilensis sp. nov, but shows rudimentary endopods in Y. antarcticus and Y. asymmetricus. With the discovery of the new species, the maximum size of species within the genus has to be corrected from earlier descriptions (Renz et al., 2013), with currently known members ranging between 0.95 mm (Y. asymmetricus) and 1.75 mm (Y. kurilensis sp. nov.). With Y. kurilensis sp. nov. included into the analysis, the definition for the genus is: small copepods (<1.75 mm). The rostrum is bifid. The proximal inner part of the leg 1 endopod is smooth. The female and male left antennule segment XXII is without a seta. The male right antennule is modified for grasping and of highly complex structure, with the main hinge between segment XXII and fused segments XXIII – XXIV. The male P 5 is uniramous or indistinctly biramous with small endopodal buds and with the distal exopod segments with or without spines. MOLECULAR PHYLOGENY To gain insights into the relationships among the evolutionarily youngest calanoid copepod groups, different species of Ryocalanoidea (genera Ryocalanus and Yrocalanus) and Spinocalanoidea (genera Spinocalanus Giesbrecht, 1888, Caudacalanus Markhaseva & Schulz, 2008) from the South Atlantic (Brazilian Basin), North Atlantic (Great Meteor Seamount) and North Pacific (Kurile-Kamchatka trench) were analysed using multi-gene approaches. Sequencing of Cytb was successful only for one individual of Yrocalanus kurilensis sp. nov. from the Kurile-Kamchatka trench and failed completely for COI for this species. Amplification and / or sequencing of Cytb was furthermore not successful for three Ryocalanus individuals from the South Atlantic, and Spinocalanus cf. magnus Wolenden, 1904 and Paraeuchaeta parvula (Park, 1978) from the North Atlantic. ITS 2 amplification / sequencing did not work for Spinocalanus abyssalis Giesbrecht, 1888 and S. aspinosus Park, 1970. Sequencing was, however, successful for nuclear genes 18 S and 28 S (see accession numbers in Table 1 for successfully sequenced genes). The integration of our data into the sequence dataset of Bradford-Grieve et al. (2014) resulted in support for the same calanoid superfamily phylogeny as the original analyses by Blanco-Bercial et al. (2011) and Bradford-Grieve et al. (2014). Adding these new data resulted in a well-supported relationship between ryocalanoidean, spinocalanoidean and clausocalanoidean copepods [Bootstrap Support (BS): 87 / 96, Bayesian Posterior Probability (BPP): 1 / 1, without and with regard of the three different codon positions for the mitochondrial genes COI and Cytb, Fig. 15]. Withinthisclade, RyocalanoideaandSpinocalanoidea form a highly supported clade (BS: 99 / 100; BPP: 1 / 1). The species of Ryocalanidae (Ryocalanus and Yrocalanus) did not form a monophyletic group, as only species of Ryocalanus were found in one clade (BS: 86 / 90; BPP: 1 / 1), while Yrocalanus was located in a supported clade with species of Spinocalanidae (Spinocalanus) and Arctokonstantinidae (Caudacalanus and Foxtonia Hulsemann & Grice, 1963) (BS: 60 / 75; BPP: 0.97 / 1). The Arctoconstantinidae were not supported as a monophyletic group in both analyses. Individuals of the same species (i. e. Yrocalanus kurilensis sp. nov. and Ryocalanus infelix) and species within the same genera (i. e. Ryocalanus, Spinocalanus and Caudacalanus) were highly supported as close relatives (BS: 100 / 100; BPP: 1 / 1, respectively). The close relationship of Ryocalanidae, Spinocalanidae and Arctokonstantinidae and the position of Ryocalanidae in the system of Calanoida was investigated using longer fragments of 18 S, 28 S and COI, and Cytb together with ITS 2 (Fig. 16). This analysis revealed a high support of species within the same genus (BS: ≥ 99 / 100 and BPP: 1 / 1, respectively, as well as high support of the close relationship of the superfamilies Ryocalanoidea and Spinocalanoidea (BS: 100 / 100; BPP: 1 / 1). Again, Ryocalanidae could not be supported as a monophyletic clade as Yrocalanus appeared in a highly supported clade together with all Spinocalanidae and Arctokonstantinidae (BS: 96 / 94; BPP: 0.95 / 0.95). Compared to the multiple-gene analyses, the single-gene analysis of 28 S resulted in similar results with high support of a Ryocalanus clade and one clade comprising Spinocalanus, Caudacalanus and Yrocalanus (results not shown). DNA SEQUENCE VARIATION There was a considerable variation in the rate of molecular evolution between the three gene loci, 18 S, 28 S and ITS 2, with highest interspecific levels of divergence within ITS 2 (0.059 – 0.539) and lowest levels in 18 S (0.001 – 0.029; Table 6). Uncorrected genetic p-distances between the genera Yrocalanus and Ryocalanus within the Ryocalanoidea were found to be higher (18 S: 0.016 – 0.022; 28 S: 0.096 – 0.12; ITS 2: 0.462 – 0.516) than between the genera Caudacalanus and Spinocalanus within the Spinocalanoidea (18 S: 0.012 – 0.016; 28 S: 0.056 – 0.069; ITS 2: 0.339 – 0.368). Highest distances were found between Spinocalanus and Yrocalanus for 18 S, Yrocalanus and Ryocalanus for 28 S and Spinocalanus and Yrocalanus for ITS 2. Within the ribosomal locus 18 S, sequence distances were low between Caudacalanus and most Ryocalanus species compared to differences between species of other genera. Intraspecific genetic divergences for Yrocalanus kurilensis sp. nov. and Ryocalanus infelix were 0 for 18 S and 28 S, and 0 – 0.005 for ITS 2.	en	Renz, Jasmin, Markhaseva, Elena L., Laakmann, Silke (2018): The phylogeny of Ryocalanoidea (Copepoda, Calanoida) based on morphology and a multi-gene analysis with a description of new ryocalanoidean species. Zoological Journal of the Linnean Society 185: 925-957
