identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
BE556840AE3F50FA91AA5580F5DEE41F.text	BE556840AE3F50FA91AA5580F5DEE41F.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Trimma charon Peinemann & Bogorodsky & Tietbohl Talas & Berumen 2026	<div><p>Trimma charon sp. nov.</p><p>Figs 1, 2, 4 F</p><p>Trimma sp. 1 – Peinemann et al. 2025: 86 (in the maximum-likelihood tree).</p><p>Common name.</p><p>Charon’s pygmygoby.</p><p>Type locality.</p><p>Saudi Arabia, Red Sea: Walih Island, 27.7897°N, 35.1630°E.</p><p>Type material.</p><p>Holotype. • ROMI 118236, 16.8 mm SL, Red Sea, Saudi Arabia, <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=35.163&amp;materialsCitation.latitude=27.7897" title="Search Plazi for locations around (long 35.163/lat 27.7897)">Walih Island</a>, 27.7897°N, 35.1630°E, outside cave of steep reef slope, 30 m depth, collected with clove oil and hand net, V. N. Peinemann, 15 May 2023 . Paratype. • ROMI 118237, 12.1 mm SL, same data as for holotype .</p><p>Diagnosis.</p><p>A species of Trimma distinguished by the following combination of characters: predorsal midline with scales (present in larger specimen); fifth pelvic-fin ray unbranched and 41–43 % length of fourth; cheek and opercle scaleless; pectoral-fin rays 14, all rays unbranched; dorsal fins VI + I, 8; first dorsal fin rounded, second and third spines subequal; no elongate dorsal-fin spines; bony interorbital width 55–62 % of pupil diameter; cephalic sensory papillae row c with 6 papillae. Live coloration translucent with a distinct, broad, orange-red midlateral stripe extending from eye to caudal-fin base and interrupted by three narrow pale bars; numerous golden spots on caudal fin extending onto caudal peduncle; iris divided into four uneven sectors (dorsal and ventral white; anterior and posterior orange, posterior smaller).</p><p>Description.</p><p>Based on holotype (16.8 mm SL) and one paratype (12.1 mm SL), the latter in parentheses if different. Dorsal fins VI + I, 8, first fin rounded in shape, second and third spine longest (but not elongate) and approximately equal in length, extending to base of second dorsal-fin spine when adpressed; some second dorsal-fin rays branched; second dorsal fin reaching posteriorly 46 % (38 %) of caudal peduncle length; anal fin I, 8, some rays branched; anal fin reaching posteriorly 51 % (33 %) of caudal peduncle length; pectoral-fin rays 14, all unbranched; pectoral-fin length 23.2 % (24.1 %) of SL, fin reaching posteriorly to above urogenital papilla; pelvic-fin I, 5, fifth ray unbranched and 41 % (43 %) length of fourth ray, which reaches posteriorly to between base of first and second anal-fin ray, pelvic-fin rays 1 to 4 with one branching point each; membrane connecting fourth and third ray extending 60 to 80 % length of fourth ray; basal membrane vestigial; no pelvic frenum; caudal fin with 2 dorsal and 2–3 ventral segmented unbranched rays, and 5 dorsal and 6 ventral segmented branched rays.</p><p>Scales in longitudinal series 24; anterior transverse scales 8 (7), posterior transverse scales 7 (8); cheek and opercle scaleless; scales present on predorsal midline; three irregular rows of scales overlapping midline immediately anterior to dorsal-fin base, followed by a short unscaled interval (likely due to loss of deciduous scales) with space for 2–3 additional scales, and then a single median scale anteriorly (Fig. 1 B); smaller specimen lacking predorsal scales, possibly due to abrasion or ontogeny; body scales ctenoid; scales on sides of nape, chest, and base of pectoral fin (including dorsally) cycloid; pectoral-fin base with two large vertically aligned scales; ventral midline anterior to pelvic-fin base with two scales in larger specimen, absent in smaller specimen; circumpeduncular scales 12; scale rows in ventral midline between base of last anal-fin ray and first procurrent caudal-fin ray 8.</p><p>Gill opening extending anteroventrally to between middle and posterior third of pupil (Fig. 1 C); anterior naris tubular, about 1.5 times as long as wide, extending anteriorly to near anterior margin of the upper lip; posterior naris oval and pore-like with raised rim, separated from fleshy margin of orbit by approximately 1.5–2 times its diameter; bony interorbital width 55 % (62 %) of pupil diameter; posterior interorbital trough with sloping sides, extending posteroventrally to between dorsalmost papilla of row a and beginning of papilla row u; no dermal ridge on midline of nape extending anteriorly from origin of first dorsal fin.</p><p>Caudal peduncle depth as percentage of caudal peduncle length 48 % (45 %); head length 31 % (28 %) of SL; as percentage of head length: horizontal eye diameter 35 % (41 %); snout length 15 % (16 %); upper-jaw length 31 % (33 %).</p><p>Number of cephalic sensory papillae in each row (Fig. 1 A, B): a = 6; b = 1 (2); c = 6; d = 3 (2); d‘ = 4; p = 6; e-anterior = 8 (9); e-posterior = 10 (8); i-anterior = 6; i-posterior = 7 (8); cs “ = 3; ot = 8 (9); os = 3; oi = 3; cp = 1; n = 1; x = 4 (5); u = 6; z = 3 (4); f = 2; r = 2; s = 1.</p><p>Color pattern, live (Fig. 2).</p><p>Body translucent with a distinct, broad, orange-red stripe extending from the eye to the base of the hypural plate, about one-third the body depth in width. This stripe is interrupted by three narrow pale bars, two positioned beneath the second dorsal fin and one on the caudal peduncle. Scale pockets along the stripe with darker orange-red pigmentation. Snout and upper jaw orange-red; anterior tubular naris blackish to dark red; lower jaw and cheek white to translucent. Iris divided into four uneven portions of alternating color; dorsal and ventral portions white and approximately equal in size; anterior and posterior portions orange, with the posterior portion smaller, about 50–60 % the size of the anterior. Caudal fin with numerous golden spots, each one-third to one-half the pupil diameter in size; spots extend anteriorly onto the posterior caudal peduncle, forming three vertically aligned spots at the base of the caudal fin and another three at the posterior margin of the peduncle. Additional golden spots present on the ventral (1–2) and dorsal (up to 4) margins of the caudal peduncle. Remaining caudal fin hyaline, membranes with scattered white iridocytes. Dorsal fins hyaline with scattered white iridocytes (fewer in smaller individual) and diffuse golden spots. Anal fin hyaline with scattered white iridocytes and a diffuse golden stripe along the central 50–60 % of the fin. Pelvic and pectoral fins hyaline and unpigmented.</p><p>Color pattern, preserved (Fig. 1 D).</p><p>Body pale white throughout. An amorphous small cluster of melanophores present posterodorsal to the eye. Sparse melanophores scattered along the midlateral region of the body in the position of the orange-red stripe seen in life. Fins hyaline, membranes of the dorsal, anal, and caudal fins with a few white iridocytes. Pectoral and pelvic fins hyaline without pigmentation. Iris mostly black in preservative, with faint silver-white visible in the anterior and posterior portions corresponding to the orange areas in life; dorsal and ventral portions fully black.</p><p>Etymology.</p><p>The species is named Trimma charon after Charon, the ferryman of the underworld in Greek mythology, who carried the souls of the dead across the river Styx in exchange for coins (Charon’s obols). The name refers to the distinctive golden spots on the caudal fin and peduncle, reminiscent of the coins. To be treated as a noun in apposition. The suggested common name is Charon’s pygmygoby.</p><p>Distribution and habitat.</p><p>The species is known only from two specimens collected at Walih Island in the northern Red Sea (27.7897°N, 35.1630°E). Both were observed at the bottom of a cave entrance at 30 m depth, resting on dead carbonate substrate. The site is a steep reef slope descending beyond 100 m, with a hard carbonate bottom that, unusually for the Red Sea, supported little structure and few living or recently dead corals. Despite extensive surveys of comparable habitats at similar depths across other Red Sea reefs, no additional specimens were found. The species may therefore be genuinely rare, or 30 m may represent the shallowest limit of its distribution, with greater abundance occurring at deeper depths. The apparent rarity of this species, or its restriction to deeper and northern habitats, is further supported by its absence from the extensive rotenone sampling stations of Coker et al. (2018) and Pombo-Ayora et al. (2024), as well as from the larval barcoding survey of Isari et al. (2017).</p><p>Comparisons.</p><p>The species most similar to T. charon is the Indo-West Pacific T. anaima . Both share a prominent orange-to-red midlateral stripe, all pectoral-fin rays unbranched, an unbranched fifth pelvic-fin ray, VI + I, 8 dorsal-fin and I, 8 anal-fin formulas, and no elongate dorsal-fin spines. Trimma charon differs from T. anaima by the presence of scales on the predorsal midline (scales absent in T. anaima; although also absent in the small paratype of T. charon) and pectoral-fin rays 14 (vs. 15–17, usually 16 rays). Live coloration readily separates the species: in T. charon the midlateral orange-red stripe is restricted to the central third of the body and interrupted by three narrow pale bars (vs. continuous and extending ventrally on the caudal peduncle in T. anaima); T. charon has distinct golden spots on the caudal and dorsal fins (absent in T. anaima, except sometimes along the dorsal and ventral margins of the caudal peduncle); and the iris of T. charon is divided into four uneven portions, with dorsal and ventral sectors white and anterior and posterior sectors orange, the posterior smaller (vs. iris uniformly bright red with a dorsomedial electric-blue stripe in T. anaima). Almost all body coloration of T. charon fades in preservative, but the four uneven iris portions remain faintly visible with subtle silver-white in the anterior and posterior portions (vs. uniform in T. anaima).</p><p>In the key to the genus Trimma by Winterbottom (2019), T. charon keys out to couplet 71, alongside T. imaii Suzuki &amp; Senou, 2009 and T. matsunoi Suzuki, Sakaue &amp; Senou, 2012 . It differs from both species in having a bony interorbital width 55–62 % of pupil diameter (vs. ~ 40 % in T. imaii and ~ 75 % in T. matsunoi) and in its live coloration, which includes a distinct midlateral orange-red stripe absent in both T. imaii and T. matsunoi . It can be further distinguished from T. imaii by having 8 dorsal-fin rays (vs. 9).</p><p>Within the Red Sea, Trimma charon is distinct from congeners. It bears some superficial resemblance to Trimma nubarum and Trimma fishelsoni, both of which combine orange-to-red body coloration with areas of transparency. Trimma nubarum additionally has faint yellow spots on the caudal and dorsal fins. However, both T. nubarum and T. fishelsoni possess an elongate filamentous second spine of the first dorsal fin, which is not elongate in T. charon .</p><p>Molecular sequences of type material</p><p>Sequences of the vouchers examined here were amplified, sequenced, and analyzed in Peinemann et al. (2025) and are made available here. GenBank accession numbers are provided in Table 1.</p><p>Key to Trimma species of the Red Sea</p><p>Habitat, depth, and relative abundance observations for Red Sea Trimma species, based on extensive field surveys by the authors, are provided in Table 2.</p></div>	https://treatment.plazi.org/id/BE556840AE3F50FA91AA5580F5DEE41F	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Pensoft via Plazi	Peinemann, Viktor N.;Bogorodsky, Sergey V.;Tietbohl Talas, Matthew D.;Berumen, Michael L.	Peinemann, Viktor N., Bogorodsky, Sergey V., Tietbohl Talas, Matthew D., Berumen, Michael L. (2026): Trimma charon, a new species of pygmygoby (Teleostei, Gobiidae) from the Red Sea with a key to the Red Sea species of the genus. ZooKeys 1293: 1-16, DOI: 10.3897/zookeys.1293.204097
