Neonesidea alyamanai, Asaba & Asaba & Tsukagoshi, 2024

Asaba, Erika, Asaba, Reina & Tsukagoshi, Akira, 2024, Three new interstitial species of the genus Neonesidea (Bairdioidea: Podocopida: Ostracoda) from the infralittoral zone in Japan, Zootaxa 5397 (3), pp. 377-396 : 387

Neonesidea alyamanai sp. nov.

( Figs. 7C, D , 8 , 9 )

Type series. All examined specimens collected at upper infralittoral zone of coarse sand beach in Motosima Islet, Tanabe City , Wakayama Prefecture (33° 43′ 56″ N, 135° 20′ 58″ E; Loc. 2 in Fig. 1 ) on 19 September 2015. Holotype: adult male ( SUM-CO-2532 ), left valve length 0.79 mm, height 0.45 mm, appendages mounted on glass slide and valves preserved in cardboard cell slide . Paratypes: 6 adult males ( SUM-CO-2526 , 2527 , 2530, 2531 , 2533 and 2534 ) and 3 adult females ( SUM-CO-2528 , 2529 and 2535 ).

Etymology. In honour of Dr Yusuke Yamana of Wakayama Prefectural Museum of Natural History for provid-ing specimens of this species. Prefix “al” formed from first letters of Latin words arena (sand) and locus (space), characterising their interstitial location.

Description. Carapace ( Fig. 8 ) characters almost corresponding to Neonesidea arenalocus sp. nov. Dorsal margin of right valve almost straight and nearly parallel to ventral margin. Posterior frill on right valve finely serrated. Approximately 15 auxiliary fine dentitions along interior postero-ventral margin in left valve, but no complementary structure in right valve.

Eye. Naupliar eye. No eye spot on carapace.

Antennula ( Fig. 9A ). Seven articulated podomeres. Chaetotaxy almost corresponding to Neonesidea arenalocus sp. nov.

Antenna ( Fig. 9 Bm and 9Bf). Five articulated podomeres. No tiny spine on terminal claw. Chaetotaxy almost corresponding to Neonesidea arenalocus sp. nov.

Mandible ( Fig. 9C ) consisting of 5 podomeres. Chaetotaxy almost corresponding to Neonesidea arenalocus sp. nov.

Maxillula ( Fig. 9D 1 , D 2 ). First (dorsal-most) endite bearing 2 claw-like and 2 simple short setae on distal end. Second endite with 3 short and 1 spatula-like (distal margin almost straight) setae on distal end. Other chaetotaxies almost corresponding to Neonesidea arenalocus sp. nov.

Fifth limb ( Fig. 9E 1 , E 2 ) consisting of 5 articulated podomeres. Chaetotaxies almost corresponding to Neonesidea arenalocus sp. nov.

Brush-shaped organ (in male) ( Fig. 9H ), consisting of asymmetrical paired branches. Chaetotaxy almost corresponding to Neonesidea arenalocus sp. nov.

Sixth limb ( Fig. 9F ). Consisting of 5 articulated podomeres. Chaetotaxy almost corresponding to Neonesidea arenalocus sp. nov.

Seventh limb ( Fig. 9G ). Consisting of 5 articulated podomeres. Chaetotaxy almost corresponding to Neonesidea arenalocus sp. nov.

Furca ( Fig. 7C, D ) bearing 7 setae. Terminal-most 2nd seta (2) nearly 2 times longer than terminal- most (1) seta. Other chaetotaxies almost corresponding to Neonesidea arenalocus sp. nov.

Caudal process ( Fig. 7C, D ). One simple seta, approximately 30 µm long.

Male copulatory organ ( Fig. 7C ). Basal capsule sub-semicircular and consisting of some lobes. Distal lobe small, short and acute. Copulatory duct arched from sub-centre of capsule to end of distal lobe.

Female genital lobe ( Fig 7D ). Semicircular with 3 to 4 times coiled spiral and bent tube inside.

Dimension. See Table 2 .

Occurrence. Known only from type locality.

Remarks. The carapace is more similar to that of Neonesidea arenalocus sp. nov. than that of N. alwakasaensis sp. nov. because of the development of a frill in the right valve. However, the spines on the frill are finer than that in N. arenalocus sp. nov. Approximately 15 auxiliary fine dentitions along the interior posteroventral margin in the left valve were observed in this new species but not in the other two new species. The capsule of the male copulatory organ is relatively smaller than that in the other two new species, and the shape of the distal lobe is distinct. The terminal-most second seta (2) of the furca is remarkably longer than that in the other two new species.

Figures

FIGURE 1. Map showing the sampling localities of Neonesidea species. Miho-Masaki Beach (Loc. 1), Motojima (Loc. 2), and Tai Beach (Loc. 3).

FIGURE 2. Sampling in Miho-Masaki Beach (Loc. 1 in Fig. 1). A, detailed location of Miho-Masaki Beach (Loc. 1). B, sampling scheme in Loc. 1, sediment materials were collected at eight points at 0.5 m intervals. C, individual number / 500 ml of Neonesidea arenalocus sp. nov. (grey bars at the back) and other ostracod species (black bars at the foreground). Materials were collected on 18 June 2015.

FIGURE 7. Copulatory organs, furcae, and caudal process of Neonesidea arenalocus sp. nov. (A, male holotype, SUM-CO2522; B, female paratype, SUM-CO-2525), Neonesidea alyamanai sp. nov. (C, male holotype, SUM-CO-2532; D, female paratype, SUM-CO-2535), and Neonesidea alwakasaensis sp. nov. (E, male holotype, SUM-CO-2542; F, female paratype, SUM-CO-2544). CD, copulatory duct; CP, caudal process; DL, distal lobe. Setae on furcae are numbered (1–7) from distal to proximal. Scale: 100 μm.

FIGURE 8. Carapace morphology of Neonesidea alyamanai sp. nov. A and B, male left and right valves, respectively (SUMCO-2526, paratype). C and D, internal view of male left and right valves, respectively (SUM-CO-2527, paratype). E and F, external view of female left and right valves, respectively (SUM-CO-2528, paratype). G and H, internal view of female left and right valves, respectively (SUM-CO-2529, paratype). I, dorsal view of male carapace (SUM-CO-2530, paratype). J, centre of internal ventral margin of male left valve (SUM-CO-2527, paratype). K, internal posterior-ventral margin of female left valve (SUM-CO-2529, paratype). Scale: 200 μm for A–I, 50 μm for J, K.

FIGURE 9. Appendages of Neonesidea alyamanai sp. nov. A, antennule; Bf, antenna of female; Bm, antenna of male; C, mandibula; D1/D2, maxillula; E1/E2, 5th limb; F, 6th limb; G, 7th limb; H, brush-shaped organ. A and Bm, male paratype, SUMCO-2531; Bf, female paratype, SUM-CO-2535; C, D2, G and H, male holotype, SUM-CO-2532; D1, E1, E2, male paratype, SUM-CO-2533; F, male paratype, SUM-CO-2534. Scale:100 μm.