Atlantapseudes sp.

Matsushima, Yoshinobu, Bâlcu, Maxim-Jean & Kakui, Keiichi, 2025, Atlantapseudes tridens sp. nov. (Tanaidacea: Apseudidae) from the Okinawa Trough, Japan, with a note on the taxonomic status of Atlantapseudes curvatus, Zootaxa 5679 (4), pp. 484-500 : 490

Atlantapseudes sp.

( Fig. 4 )

Atlantapseudes nigrichela Băcescu, 1978 , 317–322 (in part), fig. 1A.

Atlantapseudes nigrichela : Meyer & Heard 1989, table 1; Bamber 2007, 51, 52, 66; Santos & Hansknecht 2007, 29, 38, table 2; Błażewicz-Paszkowycz et al. 2011, 10–16, figs 6–9; Esquete & Cunha 2017, 64, 65, 72, table S1; García-Herrero et al. 2021b, suppl. 2, 3.

Material examined. One male (394/30687, Muzeul Național de Istorie Naturală “ Grigore Antipa,” TBL = 5.50 mm), Stn 396, Atlantic Ocean, western Portugal (41°17'4"N, 09°15'7"W), 900 m depth, silty or sandy-silty bottom, cruise “Thalassa,” September 1972 ; one ovigerous female (49217-4, Muzeul Național de Istorie Naturală “ Grigore Antipa,” TBL = 7.60 mm), Stn 407, Atlantic Ocean, western Portugal (40°33'5"N, 09°24'0"W), 740 m depth, silty or sandy-silty bottom, cruise “Thalassa,” 1 September 1972 .

Supplemental description of ovigerous female and male. Monodentate rostrum ( Fig. 4A ); spine present on mid-lateral margin of cephalothorax ( Fig. 4A ); each eye lobe with anterior spine ( Fig. 4A ); pereonites 1 and 2 without lateral spines ( Fig. 4B–E ); pereonites 3–6 with anterior spine on lateral margin ( Fig. 4F, G ); squama about 3.4 times (female) or 3.2 times (male) longer than antennal article-3 ( Fig. 4H ); pereopod-1 coxa with anterior spine; pereopod-1 propodus with six (female) or five (male) ventral and two dorsal spines; pereopod-1 dactylus with five small ventral spines; pereopod-2 coxa with spine; uropodal endopod with 23 articles; uropodal exopod with five articles (not observed in male); five paired pleopods lacking (female) or present (male) ventrally.

Remarks. Atlantapseudes sp. corresponds to the monodentate individuals of “ Atlantapseudes nigrichela . ” Băcescu (1978) described them having an anterolateral spine on the lateral margin of pereonites 1 and 2 (cf. Băcescu 1978, fig. 1A). Our re-examination of two of Băcescu’s specimens, however, revealed that the spine originates from the coxa of pereopods 1 and 2, rather than from pereonites 1 and 2. This was also true for the monodentate “ A. nigrichela ” of Błażewicz-Paszkowycz et al. (2011: fig. 6B). As the anterolateral spine on pereonite-2 was the key character distinguishing Atlantapseudes sp. from the monodentate species A. cyanea Bamber, 2007 , our finding meant that Atlantapseudes sp. is difficult to distinguish from the latter ( Table 1). Because we could not observe most appendages in detail, we refrain from making conclusions about the taxonomic status of Atlantapseudes sp.

Figures

FIGURE 4. Atlantapseudes sp., male 394/30687, Muzeul Național de Istorie Naturală “Grigore Antipa,” photomicrographs. A. Cephalothorax, dorsal view (black arrowhead = spine of rostrum; white arrowheads = anterior spines on eye lobes; grey arrowheads = mid-lateral spines on cephalothorax). B. Cephalothorax (posterior), pereonites 1 and 2, and pereonite-3 (anterior), dorsal view. C. Pereonites 1–3 and pereonite-4 (anterior), lateral view. D. Cephalothorax (right posterior), pereonite-1 (right), and pereonite-2 (right anterior), dorsal view. E. Pereonite-1 (right posterior), pereonite-2 (right), and pereonite-3 (right anterior), dorsal view. F. Pereonite-2 (posterior), pereonites 3 and 4, and pereonite-5 (anterior), dorsal view.G. Pereonite-2 (right posterior), pereonite-3 (right), and pereonite-4 (right anterior), dorsal view. B–G: black circles = anterolateral spines on pereonites; grey circles = spines on pereopodal coxae. H. Right antenna. Scales not available.