Pseudodiaptomus inopinus Burckhardt 1913

Pseudodiaptomus inopinus Burckhardt, 1913 (Figs. 3 B, 7, 8) Synonyms. Pseudodiaptomus inopinus Burckhardt (1913), 379, pl. 11 E, figs. 2 –5, 7, 8, pl. 11 F, figs. 1 –4, 9, 10, pl. 11 G, figs. 1 –4, 6– 8, pl. 12 H, figs. 1 –4, 7, 8, 10, 11; Smirnov (1929), 318, figs. 1–3; Tanaka (1966), 42, fig. 3; Mizuno and Miura (1984), 481, fig. 260; Chang and Kim (1986), 49, pl. 1, figs. 6–9; Cordell et al. (1992), 261; Soh et al. (2001), 203, fig. 3 C; Cordell et al. (2007), 214, fig. 4; Eyun et al. (2007), 265; Lee et al. (2007), 140, figs. 6–7; Chang (2009), 110, figs. 24–25. Pseudodiaptomus japonicus Kikuchi (1928), 68, pl. 18, fig. 9–12, pl. 19, figs. 13–18. Schmackeria inopinus, Shen and Tai (1962), 101; Shen and Lee (1963), 578; Shen et al. (1979), 69, figs. 27, 28. Material examined. Six females and 20 males from Tsuri-kawa R. (33 ° 50 ’ 55 ”N, 130 ° 30 ’0 8 ”E, 18 August 2009; # 10 in Fig. 1), 1 female from Imari-gawa R. (33 ° 16 ’ 22 ”N, 129 ° 53 ’ 10 ”E, 19 August 2009; # 11), 57 females and 47 males from Yukiura-gawa R. (33 ° 56 ’ 34 ”N, 129 ° 41 ’0 0”E, 19 August 2009; # 12), 4 females and 4 males from Rokkaku-gawa R. (33 ° 11 ’ 44 ”N, 130 ° 12 ’ 27 ”E, 19 August 2009; # 13), 39 females and 71 males from Chikugo-gawa R. (33 ° 11 ’ 46 ”N, 130 ° 21 ’ 36 ”E, 20 August 2009; # 14), 36 females and 57 males from Manose-gawa R. (31 ° 26 ’ 52 ”N, 130 ° 18 ’ 31 ”E, 20 August 2009; # 15), 4 females and 1 male from Hitotsuse-gawa R. (32 °0 3 ’0 8 ”N, 131 ° 28 ’ 18 ”E, 21 August 2009; # 16), 11 females from Shiomi-gawa R. (32 ° 24 ’ 57 ”N, 131 ° 37 ’0 9 ”E, 21 August 2009; # 17), 2 females and 1 male from Yasaka-gawa R. (33 ° 24 ’ 23 ”N, 131 ° 36 ’ 38 ”E, 21 August 2009; # 18), and 2 females and 8 males from Yamakuni-gawa R. (33 ° 36 ’0 9 ”N, 131 ° 10 ’ 37 ”E, 21 August 2009; # 19). All the specimens were collected by S.O. Sakaguchi and H. Ueda. One female and two male specimens from the Tsuri-kawa River were dissected for close examination of appendages. Ten female and 10 male specimens from the Tsuri-kawa River in alcohol were deposited in each the NSMT (NSMT-Cr 21263, 21264) and the USNM (USNM 1145709, 114510). Redescription. FEMALE. Body (Fig. 7 A, B) length 1.38–1.44 mm (n= 5). Second to fourth prosomites laterally with row of fine spinules along posterior margins; fourth and fifth pediger fused with rounded corners, with spiniform process dorsally, small bump terminally (indicated by arrowhead a in Fig. 7 A, C), several long spinules ventral to bump (arrowhead b), and row of spinules on posterolateral corner on each side (arrowhead c). Genital double-somite (Figs. 7 D, E, 3 B) 1.1 times longer than wide, with several spinules on each anterolateral projection, long anterolateral seta and dorsolateral row of spinules at one-third and twothird anteriorly on each side; posterior process of genital flap (indicated by arrowhead in Fig. 7 D) pointed and longer than that of P. nansei sp. nov. Caudal left rami (Fig. 7 F) slightly larger, lateral and terminal caudal setae thicker and shorter than those of P. nansei, the medial terminal seta especially swollen and as long as ramus, except one specimen from the Yukiura-gawa River with thin, long setae on both rami (Fig. 7 G). Leg 5 (Fig. 7 H) coxa with spinules on posterior and anterior surfaces. First exopodal segment with round distomedial process; terminal spine of third segment without notch at base and bearing short anterior spine with teeth medially (Fig. 7 I). Other morphological characters as in P. nansei. MALE. Body (Fig. 8 A, B) length 1.10–1.15 mm (n= 5). Second to fourth prosomites each with group of minute spinules near anteroventral corner, fifth pediger with spiniform process dorsally, and posterolateral spinules on each corner. Second urosomite with patch of minute spinules anterolaterally and ventral transverse rows of spinules (Fig. 8 C). Right antennule (Fig. 8 D) segmentation pattern and setal formula as in P. nansei; serration of 18 th with longer teeth than those of P. nansei; length ratios of 18–20 th segments to 17 th segment 1.5, 1.4, 2.6, respectively. Left leg 5 (Fig. 8 E) without spinules at base of distal smaller process of basoendopod; second exopodal segment of 5 specimens paddle-shaped among 20 specimens examined (Fig. 8 F). Right leg 5 first exopodal segment with proximomedial spinule and distolateral spine extending more than mid length of second segment with small lateral spine; third segment not swollen proximally. Other morphological characters as in P. nansei. Remarks. Diagnostic characters of our specimens closely agree with Burckhardt’s (1913) original description from Taifu Lake of the Yangtze River delta. However notable differences were observed in the following two respects. First, the female leg 1 is much shorter than that illustrated by Burckhardt (1913, plate 11 G, fig. 6); e.g. the second exopodal segment is as long as wide in our specimens as in the new species, but two times longer than wide in the original description. The proportions of the leg 1 segments illustrated by Lee et al. (2007) and Chang (2009), who provided illustrations of P. inopinus from Korea, are similar to those of our specimens. Second, a clear row of spinules is present medially to the conspicuous dorsal spinule of the female fifth pediger in Burckhardt’s illustration (plate 11 E, fig. 5), whereas in our specimens a spinule row is present ventrally to the bump. Lee et al. (2007) and Chang (2009) described another type of ornamentation in which no spinule rows were present except for those on the distolateral corner of the somite. Considering these morphological differences among specimens from different localities, they may be a species complex. However, we call them P. inopinus for convenience in this study. Revising this potential complex worldwide is clearly beyond the scope this paper. This species occurred in most river estuaries in Kyushu but was never found in collections from the Nansei Islands.Published as part of Sakaguchi, Sakiko Orui & Ueda, Hiroshi, 2010, A new species of Pseudodiaptomus (Copepoda: Calanoida) from Japan, with notes on the closely related P. inopinus Burckhardt, 1913 from Kyushu Island, pp. 52-68 in Zootaxa 2623 on pages 62-65, DOI: 10.5281/zenodo.19812

Acartia (Acanthacartia) cagayanensis Sakaguchi & Ueda 2020, sp. nov.

<i>Acartia</i> (<i>Acanthacartia</i>) <i>cagayanensis</i> sp. nov. <p>(Figs. 1–3)</p> <p> <b>Material examined.</b> Female holotype (NSMT-Cr 28389) and male allotype (NSMT-Cr 28390) collected from the mouth of the Cagayan River on February 2, 2009. Paratypes: 2 females and 2 males were collected from the mouth of the Cagayan River on February 2, 2009 (NSMT-Cr 28391– 28394) and 10 female specimens were collected from the river on February 16, 2010 (NSMT-Cr 28395). Furthermore, 46 females and 2 males were collected from the mouth of the Pata River on February 15, 2010.</p>Published as part of <i>Sakaguchi, Sakiko Orui & Ueda, Hiroshi, 2020, A new species closely related to Acartia sinjiensis (Copepoda: Calanoida), from river estuaries of northern Luzon, the Philippines, pp. 532-544 in Zootaxa 4881 (3)</i> on page 534, DOI: 10.11646/zootaxa.4881.3.6, <a href="http://zenodo.org/record/4283948">http://zenodo.org/record/4283948</a&gt

Pseudodiaptomus nansei Sakaguchi & Ueda, 2010, sp. nov.

Pseudodiaptomus nansei sp. nov. (Figs. 2, 3 A, 4–6) Synonym. Pseudodiaptomus inopinus Burckhardt, 1913, Oka et al. (1991), 85, fig. 3. Type material. Female holotype (NSMT-Cr 21259), male allotype (NSMT-Cr 21260) dissected in lactophenol and mounted on 8 glass slides using CMC- 10, aqueous mounting medium (Masters Company, Inc., Wood Dale, IL), and undissected 8 female and 10 male paratypes (NSMT-Cr 21261, 21262) in alcohol were deposited in the NSMT. Undissected 10 female and 10 male paratypes in alcohol were deposited in the USNM (USNM 1145707, 1145708). All type specimens (57 females and 48 males including the sequenced specimens) were collected from the mouth of the Hirakubo-gawa R. (24 ° 35 ’ 39 ”N, 124 ° 18 ’ 48 ”E, 10 October 2008, colls S.O. Sakaguchi and H. Ueda; # 1 in Fig. 1) of Ishigaki-jima Island on 10 October 2008. Other material examined. Five females and 4 males from the Miyara-gawa R. (24 ° 21 ’ 31 ”N, 124 ° 12 ’ 42 ”E, 10 October 2008; # 2 in Fig. 1), southern Ishigaki-jima Island; 12 females and 4 males from the Yakashimoguchi-gawa R. (26 ° 28 ’ 50 ”N, 127 ° 50 ’ 48 ”E, 12 October 2008; # 3) on the west coast, 1 male from the Tokuhina-gawa R. (26 ° 27 ’ 16 ”N, 127 ° 51 ’ 23 ”E, 12 October 2008; # 4) and 8 males from the Ginozafukuchi-gawa R. (26 ° 28 ’ 22 ”N, 127 ° 57 ’05”E, 12 October 2008; # 5) on the east of central Okinawajima Island; 1 female from the Chinaze-gawa R. (28 ° 22 ’ 46 ”N, 129 ° 26 ’ 47 ”E, 15 October 2008; # 6) and 1 female from the Kawauchi-gawa R. (28 ° 16 ’ 17 ”N, 129 ° 18 ’ 28 ”E, 15 October 2008; # 7) on the western coast, and 2 females and 8 males from the Yakugachi-gawa R. (28 ° 15 ’ 17 ”N, 129 ° 24 ’ 14 ”E, 15 October 2008; # 8) and 5 females and 25 males from the Ura-gawa R. (28 ° 24 ’ 36 ”N, 129 ° 35 ’ 29 ”E, 15 October 2008; # 9) on the eastern coast of Amami-ohshima Island. All the specimens were collected by S.O. Sakaguchi and H. Ueda. Description. FEMALE (HOLOTYPE). Body (Fig. 2 A, B) length 1.13 mm; prosome length 0.65 mm. Forehead rounded in dorsal and lateral views. Cephalosome and first pediger fused; fourth and fifth pedigers fused; dorsal and lateral surfaces of pedigers smooth, except 3–4 spinules on each posterolateral rounded corner of fifth pediger. Urosome symmetrical. Genital double-somite 1.3 times longer than wide, with several spinules on each anterolateral projection, long anterolateral seta and dorsolateral row of spinules at one-third anteriorly on each side; genital operculum (Figs. 2 C, D, 3 A) with broad hyaline frill laterally and rounded posterior process (indicated by arrowhead in Fig. 2 C); second urosomite with dorsal row of spinules at on each side; genital double-somite and second and third urosomites with posterior row of spinules along dorsal margin. Caudal rami (Fig. 2 E) symmetrical, 3.3 times longer than wide; 1 lateral and 4 terminal caudal setae thin and dorsal seta short and sinuate; lateral medial terminal caudal seta (longest caudal seta) twice longer than ramus. Antennule (Fig. 2 F) 22 -segmented with incomplete suture between sixth to seventh segments; setal formula as follows: 1 = 1 +ae (aesthetasc), 2 = 3 + ae, 3 = 2 + ae, 4 = 2 + ae, 5 = 3 + ae, 6 = 1 (spiniform), 7 = 2 + ae, 8 = 2 + ae, 9 = 2 + ae, 10 = 2 (1 spiniform) + ae, 11 = 2 + ae, 12 = 2 + ae, 13 = 2 + ae, 14 = 2 + ae, 15 = 2, 16 = 2, 17 = 2 + ae, 18 = 1, 19 = 1, 20 = 2, 21 = 2, 22 = 6 + ae; 20 th segment with seta bearing unique row of dense hairs (Fig. 2 G). Antenna (Fig. 4 A) coxa and basis and first endopodal segment completely fused; coxa with seta; basis with 2 setae; first endopodal segment with 2 setae, second segment with 9 subterminal and 7 terminal setae; exopod 5 -segmented, with setal formula 1, 5, 1, 2, 3. Mandible (Fig. 4 B) basis with 4 setae; exopod 5 -segmented, with seta on each first to fourth segments and 2 setae on fifth segment; endopod 2 -segmented, with 4 setae on first segment and 9 setae. Maxillule (Fig. 4 C) praecoxal arthrite with 9 spines and 6 setae; coxal endite with 4 setae, epipodite with 9 setae; basal endites with 3 and 5 setae, exite with seta; exopod with 9 seta; endopod 3 -segmented, with setal formula 4, 4, 7 Maxilla (Fig. 4 D) praecoxal with 4 setae on first endite and 3 setae on second endite; coxal endites with 3 and 3 setae; basal endite with 4 setae; endopod 4 -segmented, with setal formula 2, 3, 2, 2. Maxilliped (Fig. 4 E) coxa with 2, 3, 4 setae on first to third endites; basis with 3 setae; endopod 6 - segmented, with setal formula 2, 3, 2, 3, 3, 4; 2 setae on second segment and seta on third segment of endopod modified as shown in Fig. 4 F and seta on fourth segment short and bearing teeth-like spinules. Legs 1–4 (Fig. 5 A–D, Table 1). Terminal spines on third exopodal segments of legs 1–3 with row of hairs along distal half of medial margin. Coxa Basis Exopodal segment Endopodal segment Leg 1 0-1 0-0 I- 1; 0-1; II, I, 3 0-1; 0-1; 1, 2, 3 Leg 2 0-1 0-0 I- 1; I- 1; II, I, 5 0-1; 0-2; 2, 2, 4 Leg 3 0-1 0-0 I- 1; I- 1; II, I, 5 0-1; 0-2; 2, 2, 4 Leg 4 0-1 1 -0 I- 1; I- 1; II, I, 5 0-1; 0-2; 2, 2, 3 Leg 5 (Fig. 5 E) symmetrical; coxa with spinules anterolaterally; basis with proximal and distal spinules medially, posterior seta and anterior spinules laterally. Exopod 3 -segmented; first segment with pointed distomedial process, distolateral spine, and anterodistal row of spinules; second segment with 1 large medial and 1 small lateral spines; third segment representing long terminal spine with notch (Fig. 5 F) and short anterior spine at base (Fig. 5 G). MALE (ALLOTYPE). Body (Fig. 6 A, B) length 0.90 mm, prosome length 0.54 mm. Cephalothorax as in female. Fifth pediger with no spinules on each posterolateral rounded corners. Genital somite with small posterolateral process on each side; second urosomite ventrally with transverse rows of spinules (Fig. 6 C); second to fourth urosomites fringed with spinules on whole margins. Right antennule (Fig. 6 D) 20 -segmented, with sixth to seventh segments incompletely fused; setal formula as follows: 1 = 1 + ae, 2 = 3 + ae, 3 = 2 + ae, 4 = 1, 5 = 2 + ae, 6 = 1, 7 = 2 + ae, 8 = 1 (spine), 9 = 2 + ae, 10 = 1 (spine) + ae, 11 = 2 (1 spine) + ae, 12 = 2 (1 spine) +ae, 13 = 2 (1 spine) + ae, 14 = 2 + ae, 15 = 2 + ae, 16 = 2 + ae, 17 = 2 (1 spine), 18 = 2 (1 pine), 19 = 3 (2 spine), 20 = 9 + 2 ae; 18 th segment with serrate ridge; 19 th segment with hirsute proximal ridge; length ratios of 18–20 th segments to 17 th segment 1.9, 1.6, 3.2, respectively. Leg 5 (Fig. 6 E, F) coxa with spinule patch on both surfaces. Left basis and endopod completely fused, produced into 2 large medial processes, medial one large and laterally curved with anterior row of long spinules at mid length, and distal one smaller, and discontinuously tapering into thin spiniform process with many spinules on posterior surface of base, and with lateral seta and anterolateral row of spinules. Left exopod 2 -segmented; first segment rectangular with spine and spinules at distolateral corner, second segment thumb-shaped with lateral notch one-third from tip, proximomedial row of spinules, proximolateral spine, 2 setae each at notch and tip. Right leg basis with 2 medial processes, proximal one rounded, tip bearing hairlike spinule, and distal one triangular, and with proximolateral spinules, lateral seta and distal spinules. Exopod 3 -segmented; first segment with fused thick curved terminal spine extending at most to half length of second segment, with proximomedial spinule and anterolateral spinules; third segment shaped falcate long, proximally swollen along lateral margin with maximum width at proximal one-third, bearing medial seta and medial triangular process with seta, terminal third with medial spinules. Other appendages as in female. Variability. The body length ranged from 1.10–1.13 mm (n= 5) in females and 0.86–0.91 mm (n= 5) in males, and the prosome length 0.65–0.67 mm in females and 0.54–0.55 mm in males. One female specimen from the Yakugachi-gawa River had slightly swollen setae on the caudal rami (Fig. 2 H). The male first urosomite lateral spinules and second urosomite ventral spinule rows varied and in some specimens the rows resembled those of P. inopinus Burckhardt, 1913 described below. Male left leg 5 posterior spinules patch on the fused basis-endopod segment was absent in specimens from the Amami-ohshima Island. Male left leg 5 the second exopodal segment of a specimen from the Ura-gawa River was the intermediate form between thumb- and paddle-types by having a weak lateral depression, and a spinule patch on the anterior surface (Fig. 6 G), which was absent in the thumb-type specimens. Etymology. The species name is a noun in apposition derived from the Nansei Islands, the distribution range of the species. Remarks. This new species was collected from three islands of the Nansei Islands in southern Japan: Ishigaki-jima, Okinawa-jima and Amami-ohshima Islands (Fig. 1), but not found in the samples from Kyushu and the other islands of the Nansei Islands. Salinity and temperature at the sampling sites of the species ranged from 0.3–25.1 and from 21.6–29.7 °C, respectively. This species was especially dominant at the site of the Hirakubo-gawa River, Ishigaki-jima Island, where the salinity ranged from 3.1–6.2. Oka et al. ’s (1991, fig. 3) specimens described as P. inopinus from Iriomote-jima, Ishigaki-jima, Okinawa-jima, Amami-ohshima and Tanegashima Islands of the Nansei Islands are here attributed to P. nansei. The authors published illustrations showing the female caudal rami with thin terminal setae and the male right leg 5 with the third segment swollen at the proximal one-third. Oka et al. (1991) and Oka and Saisho (1994) also recorded the dominance of P. nansei in brackish waters of the Nakama-gawa River (salinity 1.5), Iriomote-jima Island, and the Sumiyo-gawa River (salinity 21.8 ± 7.5), Amimi-oshima Island, respectively.Published as part of Sakaguchi, Sakiko Orui & Ueda, Hiroshi, 2010, A new species of Pseudodiaptomus (Copepoda: Calanoida) from Japan, with notes on the closely related P. inopinus Burckhardt, 1913 from Kyushu Island, pp. 52-68 in Zootaxa 2623 on pages 53-61, DOI: 10.5281/zenodo.19812

A new species closely related to Acartia sinjiensis (Copepoda: Calanoida), from river estuaries of northern Luzon, the Philippines

Sakaguchi, Sakiko Orui, Ueda, Hiroshi (2020): A new species closely related to Acartia sinjiensis (Copepoda: Calanoida), from river estuaries of northern Luzon, the Philippines. Zootaxa 4881 (3): 532-544, DOI: https://doi.org/10.11646/zootaxa.4881.3.

Alien or native to Japan? : whether has a planktonic copepod recently described from Shimizu Port as a new species been introduced?

The planktonic calanoid copepod Centropages maigo Ohtsuka, Itoh & Mizushima, 2005 has been described from Shimizu Port, Middle Japan, as a new species, which was supposed to have been introduced from southeastern Asia via ballast water. Since it was first discovered from a sample collected from Japan in 1979, additional records of its occurrence all over Japan have been rapidly increasing. Whether this species is alien or native to Japan was investigated on the basis of the biology and zoogeography of other planktonic copepods. It is likely that C. maigo is widely distributed around Japan as a native species