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Detaylı Bibliyografya
Asıl Yazarlar:	Chen, Jia-Jie, Zhao, Bei-Jia, Yang, Ning-Ya, Zhang, Hui, He, You, Zhang, Han-Ye, Wang, Xiao-Dong, Zhong, Jun-Sheng
Materyal Türü:	Recurso digital
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Baskı/Yayın Bilgisi:	Zenodo 2026
Konular:	Biodiversity Taxonomy Animalia Chordata Ophidiiformes Ophidiidae Neobythites Neobythites nanhaiensis
Online Erişim:	https://doi.org/10.5281/zenodo.18637564
Etiketler:	Etiketle Etiket eklenmemiş, İlk siz ekleyin!

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Neobythites nanhaiensis sp. nov.Figs 1, 2English name: South China Sea cusk; Chinese name: 南海新鼬鳚Type material.Holotype • ECSFRI 28760, 135.70 mm SL, sex uncertain, South China Sea, near Nan’an Reef (5°23.08'N, 112°11.41'E), depth 400 m, collected by trawling by Bei-Jia Zhao in March 2025 (Fig. 1). Paratypes • ECSFRI 28757, 119.52 mm SL; ECSFRI 28758, 121.26 mm SL; ECSFRI 28759, 144.51 mm SL; ECSFRI 28765, 106.32 mm SL; ECSFRI 28843, 133.65 mm SL, female; ECSFRI 28844, 142.56 mm SL, male; ECSFRI 28845, 132.23 mm SL, female; ECSFRI 28846, 117.43 mm SL, female; ECSFRI 28847, 126.42 mm SL, female; ECSFRI 28848, 122.42 mm SL, female; ECSFRI 28849, 114.73 mm SL, female (cleared and stained); ECSFRI 28850, 118.44 mm SL; ECSFRI 28851, 106.29 mm SL, female. All collected with holotype. Sex uncertain except where noted (Fig. 2).Diagnosis.Neobythites nanhaiensis is distinguished from all currently known congeners by the presence of two (rarely three) distinct black ocelli on the mid-flank (vs flank ocelli absent in all other Neobythites species) (Table 2). It further differs from other ocellated species (which possess ocelli on the dorsal fin) by the absence of ocelli, stripes, or dark margins on all median and paired fins. Additionally, it can be identified by the following combination of meristic features: dorsal-fin rays 107 (90–115), originating above 4 th vertebra; anal-fin rays 93 (80–94), originating below 16 th dorsal-fin ray (13 th – 16 th) and 20 th vertebra (17 th – 21 st); pectoral-fin rays 25 (21–27); pelvic-fin rays 2; caudal-fin rays 8 (6–10); total vertebrae 62 (58–64), precaudal vertebrae 13, caudal vertebrae 49 (not including ural centra); long gill rakers on outer face of first arch 9–11; pseudobranchial filaments 4–8; preopercular spines 2; snout shorter than horizontal eye window; pelvic-fin length 7.49–11.57 % SL; longest gill filament 5.27–7.53 % HL; vomerine tooth patch triangular with each side concave; body yellowish to light brownish-yellow, with two (rarely three) black ocelli on flank.Neobythites nanhaiensis sp. nov. is distinguished from other regional congeners by a suite of meristic and morphological characters. Most notably, it possesses two (rarely three) distinct ocelli on the mid-body flank, a feature absent in N. marginatus, N. steatiticus, and N. unimaculatus. Furthermore, the new species lacks a dorsal-fin ocellus, which is present in both N. steatiticus and N. unimaculatus. In terms of fin-ray counts, N. nanhaiensis has 90–115 dorsal-fin rays and 80–94 anal-fin rays, overlapping with but extending to higher counts than its congeners (Table 2). The count of developed gill rakers (9–11) is lower than in N. marginatus and N. steatiticus (11–14) but higher than in N. unimaculatus (7–9). Vertebrally, the new species (58–64 total vertebrae) has a higher count than N. steatiticus (53–57) and N. unimaculatus (51–52), while overlapping with N. marginatus (61–66). Ecologically, N. nanhaiensis is currently known only from a depth of ~ 400 m in the South China Sea, distinguishing it in both depth range and geographic distribution from the compared species.Comparative data for congeners follow Nielsen (1999), Nielsen et al. (1999, 2009), Li and Zhang (2011), Iwamoto and McCosker (2014), Uiblein and Nielsen (2018), Koeda and Ho (2019), Fricke et al. (2025); data for N. nanhaiensis are from the present study.Description.Morphometric measurements and counts are summarized in Table 3. Condition of holotype given first, followed by those of paratypes in parentheses, if different. Body elongate, compressed, depth at dorsal-fin origin 5.9 in SL, at anal-fin origin 6.1 in SL. Head length 5.1 (4.8–5.3) in SL; snout rounded, shorter than horizontal eye window, length 6.2 in HL; eye circular, horizontal width 4.2 (3.7–4.8) in HL; interorbital space narrow, width 6.1 in HL; postorbital length 1.7 in HL.Pectoral fin short, length 1.5 in HL, tip slightly pointed, not reaching vertical through anus. Pelvic fin inserted below hind margin of preopercle, length 2.38 in HL, tip not reaching anus; inner ray slightly longer than outer. Dorsal-fin origin above pectoral-fin, base length 1.26 (1.26–1.30) in SL; anal-fin base length 1.58 (1.54–1.69) in SL; both continuous with caudal fin. Caudal fin slender, slightly pointed, length 0.60 (0.42–0.76) in horizontal eye window. Small cycloid scales embedded on head, body, and dorsal-and anal-fin bases. Lateral line single, at upper one-fourth of body, from upper part of gill opening, indistinct posteriorly.Mouth large, subterminal; upper-jaw length 2.3 in HL; maxilla extending beyond posterior margin of eye window; posterior end truncated. Two nostrils: anterior nostril with concave rim, situated anteroventrally to snout; posterior nostril larger, positioned anteroventrally to eye and above horizontal through anterior nostril. Symphysis of premaxillae notched and edentate (Figs 1, 2).Premaxilla, dentary, vomer, palatine and basibranchial with villiform teeth; vomerine tooth patch triangular, each side concave (Fig. 3 A); palatine tooth patch broad, gradually narrowing anteriorly; two median basibranchial tooth patches: anterior patch with broad anterior and narrow posterior part, posterior patch teardrop-shaped, 1 / 4 length of anterior, separated from palatine tooth patch by space equal to its length (Fig. 3 B).Opercle with one strong, falcated spine, its tip almost reaching posterior margin of opercle. Preopercle with two spines on posterior margin. Gill opening wide, reaching dorsal edge of pectoral-fin base. Developed gill rakers on first arch 9–11, elongated rod-shaped; pseudobranchial filaments short (Fig. 4).Osteology (Fig. 5). First neural spine short, ~ 1 / 2 length of second; bases of first three neural spines not thickened; parapophyses on vertebrae 7–13, vertebra 7 asymmetrical; pleural ribs on vertebrae 1–13: ribs 1 and 2 short rod-shaped, rib 3 with expanded base tapering to slender tip, ribs 4 and 5 rod-shaped anteriorly and slender posteriorly, ribs 6 and 7 slender; epipleurals on pleural ribs of vertebrae 3–5, that on vertebra 3 with expanded base; epineurals absent. Six anal-fin pterygiophores anterior to first haemal spine.Otolith (Fig. 6, Table 4). Sagittal otolith oval, length 23.81–26.14 % HL, length / depth ratio 1.56–1.80; ventral and anterior margins smoothly curved, dorsal margin crenate; distal surface slightly concave, proximal surface slightly convex; sulcus groove mesial, shallow, horizontal, archaesulcoid, length 16.62–20.19 % HL; both colliculums present, ostial elongated, caudal oval; cristae superior and inferior poorly developed; rostrum absent; excisura absent; dorsal depression very shallow; ventral depression absent.Coloration.When fresh (Figs 1 A, 2), body yellowish to pale brownish-yellow, with two black ocelli on flank (rarely three, ECSFRI 28765, Fig. 2 D): first ocellus between pectoral-fin tip and above anus, slightly larger, second ocellus mid-flank below middle of dorsal fin, somewhat dorsally, third ocellus (if present) between anterior two; ocelli usually covering 5–7 vertical scale rows; dorsal and anal fins dusky with pale bases, without ocellus; pectoral, pelvic and caudal fins dusky. When preserved, color similar but paler. Oral cavity pale or with sparse melanophores, including underside of tongue, lower gill arches and rakers; mouth roof behind vomer, inner opercle, and upper gill arches dusky; peritoneum black.Distribution.Known only from the type locality in the South China Sea near Nan’an Reef (5°23.08'N, 112°11.41'E), at a depth of 400 m.Etymology.The specific name nanhai is named after the South China Sea, known as ‘ Nan Hai’ (南海) in Chinese, which is the currently known only locality for this species, from which the type specimens were collected near Nan’an Reef.Common name.Both the Chinese and English common names of this species are derived from the South China Sea, its only known habitat. Thereby, the names “ 南海新鼬鳚 ” (Nán H&abreve;i X&imacr;n Yòu Wèi) and “ South China Sea cusk ” are established, consistent with the geographical origin referenced in the specific name nanhai.Mitogenomic characteristicsThe complete mitochondrial genome of Neobythites nanhaiensis sp. nov. (accession no. PX 512822, ECSFRI 28760) is 17,287 bp in length and exhibits the typical vertebrate structure, comprising 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and one control region. All genes are encoded on the heavy strand except for ND 6 and eight tRNAs. The overall base composition shows a distinct A + T bias (55.1 %). Most PCGs initiate with the standard ATG codon, except COX 1 (GTG), ND 1, and ND 3 (ATA). A subset of PCGs possesses incomplete stop codons (TA or T). Consistent with many teleosts, the mitogenome shows a codon usage bias, with leucine being the most frequently encoded amino acid. A notable structural feature is the absence of the DHU arm in tRNA - Ser, a conserved trait among metazoans (Suppl. material 1). The Ka / Ks ratio for most PCGs indicates strong purifying selection, while the notably elevated ratio for ATP 6 (1.6173) suggests potential positive selection or relaxed constraints (Fig. 7, Suppl. material 3: tables S 4 – S 6).Phylogenetic analysisBased on the COI gene, both maximum likelihood and Bayesian inference analyses (Fig. 8) consistently recovered Neobythites nanhaiensis sp. nov. as a distinct, fully supported monophyletic lineage (ML BS = 100, BI PP = 1). The species was robustly placed as the sister to a well-supported clade comprising seven congeners: N. analis, N. bimaculatus, N. gilli, N. marginatus, N. soelae, N. stelliferoides, and N. stigmosus (ML = 88.7, BI = 0.98). However, the internal branches within N. nanhaiensis showed notably variable and sometimes low support (ML BS as low as 60.7; BI PP ranging from 0.175 to 0.636), indicating some uncertainty in the fine-scale relationships among its specimens.In contrast, phylogenetic analyses based on the concatenated set of 37 mitochondrial genes (13 PCGs, 2 rRNAs, and 22 tRNAs) (Fig. 9) provided overwhelming support for the species’ validity and internal coherence. The mitogenome (37 - gene) tree robustly identified N. nanhaiensis as a distinct lineage and resolved it as a maximally supported sister to N. marginatus. Furthermore, this analysis confirmed the genetic cohesiveness of N. nanhaiensis, with key internal nodes receiving consistently high support (ML bootstrap values ranging from 75 % to 100 %; Bayesian posterior probabilities from 0.67 to 1.0).In summary, the consistent and high support for N. nanhaiensis as a distinct monophyletic unit across all analyses — using both the single mitochondrial COI gene marker and the complete mitogenome (37 genes) — provides robust molecular evidence for its recognition as a new species. While the COI gene revealed some phylogenetic uncertainty at the population level, the stronger and more consistent nodal support from complete mitogenome data firmly establishes the genetic distinctness and internal coherence of N. nanhaiensis.

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