A new species of Hetereleotris (Perciformes: Gobiidae) from the Red Sea.

A new species of the genus Hetereleotris is described from the Gulf of Aqaba, Red Sea, on the basis of two specimens. Hetereleotris psammophila sp. nov. is unique among the species of the genus Hetereleotris, except for H. diademata, in lacking scales and head pores. The new species differs from the morphologically similar H. diademata in having fewer rays in the second dorsal and anal fins, and in coloration. The habitat preference of the new species for open sand area close to coral reefs in 8-21 m and its nocturnal habits are unusual for species of the genus Hetereleotris.

Gymnoxenisthmus tigrellus, new genus and species of gobioid fish from the Red Sea (Gobioidei: Xenisthmidae).

Gymnoxenisthmus tigrellus is described from the 15.2 mm SL holotype collected from the Farasan Archipelago, southern Red Sea. It is distinguished from other xenisthmid genera in having the following combination of characters: head pores absent; no scales; first dorsal fin with five spines; at least some dorsal-, anal- and pectoral-fin rays branched; pelvic fin with a spine and five unbranched rays. Evaluation of available (mostly external) characters suggests the new genus is the sister group of a clade consisting of Rotuma, Tyson and Allomicrodesmus.

Two new species of Cabillus (Perciformes: Gobiidae) and the first record of Cabillus macrophthalmus from the Western Indian Ocean.

Two new species of the gobiid genus Cabillus, C. nigromarginatus sp. nov. and Cabillus nigrostigmus sp. nov. are described. Cabillus nigromarginatus (from Rodrigues, Western Indian Ocean) is distinguished from congeners by having 18-20 pectoral-fin rays; predorsal area naked; two scales with enlarged ctenii ventrally and dorsally at the caudal-fin base; head with anterior and posterior oculoscapular, and preopercular canals, with pores σ, λ, κ, ω, α, ß, ρ, ρ1, ρ2 and γ, δ, ε respectively; the body with four midline lateral blotches, with two or three of them expanding upwards in dorsal saddles; a dark triangular blotch at caudal-fin base; and predorsal with pigmentation at lateral edges forming a rectangle. Cabillus nigrostigmus (from the Red Sea) is distinguished from its congeners by having 19 pectoral-fin rays; transverse scale series 7; nape scaled, median predorsal scales 7; body depth 5.8-6.0 in SL; snout length 1.5-1.9 in eye diameter; caudal-peduncle depth in its length 2.4-2.5; a broad dark brown bar below first dorsal fin beginning anteriorly at the level of fourth spine of the first dorsal fin; elongate black blotch along posterior half of first dorsal fin extending into the sixth spine and adjacent membranes; and midlateral black spot at the end of caudal peduncle followed by S-shaped dark bar. Cabillus macrophthalmus is recorded for the first time in the Western Indian Ocean (Red Sea and Seychelles) and redescribed.

Four new species of coral gobies (Teleostei: Gobiidae: Gobiodon), with comments on their relationships within the genus.

Four new species of the coral-associated gobiid genus Gobiodon were discovered in the Red Sea. Although several of these species are common not only in the Red Sea but also in the Indian and western Pacific Ocean, they have not been described before. Detailed descriptions of the four species are based on morphological and molecular genetic (mitochondrial 12s and 16s rRNA) investigations. The new species, like most species of the genus, lack scales and have species-specific life colouration. Gobiodon bilineatus sp. nov. is the closest relative to G. quinquestrigatus (Valenciennes) and of G. sp. D (Munday et al.), and has five distinct, blue lines on the head as juveniles and subadults, which disappear in adults, and which are often uniformly orange-red with two distinct, vertical blue lines through each eye. Gobiodon irregularis sp. nov. has been confused with the former new species in the past, and is closely related to G oculolineatus Wu, but is unmistakable in live colouration. Juveniles are characterised by a transparent body, red bars on the head with bluish to greyish interspaces, and irregular red lines and dots on the nape and dorsally on the body. Adults are usually uniformly brown or green-brown, with only remnants of the bars through the eye and below the orbit. Gobiodon ater sp. nov. is a small, entirely black species and can be easily confused with other black species, although it is genetically clearly distinct from G. ceramensis Bleeker and its black relatives. Gobiodonfuscoruber sp. nov. is likely to be the closest relative of G ater sp. nov., but is uniformly reddish-brown or brown, has bright median fin margins (at least in the Red Sea), and grows considerably larger than G. ater. It has been genetically determined that G. fuscoruber sp. nov. is identical with an Indian Ocean/western Pacific species that has been called G. unicolor Castelnau by several authors. However, examination of the holotype of G unicolor, including the original description, revealed that the type species and original description are clearly different from the species frequently called G. unicolor. The holotype resembles G. histrio (Valenciennes) and the name G. unicolor must therefore be considered a junior synonym of G. histrio. As a consequence, a new name for this species is provided.

Description of a new species of the cardinalfish genus Pseudamiops (Perciformes, Apogonidae) from the Red Sea.

A new species of pseudamine cardinalfish, Pseudamiops springeri, is described from five specimens collected in the Red Sea. It may be distinguished from the four known species of Pseudamiops in having 13 pectoralfin rays, pseudobranch with 2-4 filaments, no canine teeth on the vomer, anterior nostril with a conspicuous skin flap and genital opening flanked by two slender papillae. Pseudamiops springeri is closest to its Western Indian Ocean congener P. pellucidus Smith.

Acanthoplesiops cappuccino, a new species of acanthoclinine fish from the Red Sea (Teleostei: Plesiopidae) .

Acanthoplesiops cappuccino is described from the 16.4 mm SL holotype collected from Jeddah, Saudi Arabia, Red Sea. The following combination of characters distinguishes it from congeners: dorsal-fin rays XVIII,4; anal-fin rays VII,4; pectoral-fin rays 18; caudal fin not connected to last rays of dorsal and anal fins by membrane; and caudal peduncle with a pale yellowish brown bar, which extends broadly on to caudal fin. An underwater photo of the anaesthetised holotype is provided, as well as one of the freshly dead holotype and only known specimen of the similar species A. naka. Tables summarizing diagnostic characters of the six known species of Acanthoplesiops are included. congeners by possessing both rostral and maxillary barbels; having the last simple dorsal-fin ray weak and smooth; the lateral line complete, with 40-42+1 pored scales; ½7-½8/1/3½ scales in transverse line from dorsal-fin origin to pelvic-fin origin; 4½ scales between lateral line and anal-fin origin. Hypselobarbus kolus is considered a synonym of H. curmuca, which is redescribed: it is distinguished from all congeners by possessing maxillary barbels only; the last simple dorsal-fin ray weak and smooth; 41-43+1 lateral-line scales; 9-10/1/4½-5 scales in transverse line between origins of dorsal and pelvic fins; and 5½-6 scales between lateral line and anal-fin origin.  

Epinephelus geoffroyi (Klunzinger, 1870) (Pisces: Serranidae), a valid species of grouper endemic to the Red Sea and Gulf of Aden.

The grouper Epinephelus geoffioyi (Klunzinger), type locality Red Sea, previously regarded as a synonym of E. chlorostigma (Valenciennes) is recognized as a valid species. It is differentiated from E. chlorostigma by having 25-29 (modally 27) gill rakers vs. 23-26 (modally 24), a more angular anal fin, the dark spots on the abdomen more widely separated, and lacking a clear white margin posteriorly on the caudal fin. The missing holotype of E. geoffroyi was found at the Staatliches Museum für Naturkunde Stuttgart (SMNS 233, 191 mm). Epinephelits chlorostigma is wide-ranging from the Gulf of Aden and east coast of Africa to Samoa; it is reported from the depth range of 32-280 m. Epinephelus geoffroyi is presently known only from the Red Sea and Gulf of Aden at depths of 3-32 m. Illustrations are provided for three other species of groupers with numerous small dark spots, E. areolatus (Forsskål), E. gabriellae Randall & Heemstra, and E. polylepis Randall & Heemstra, that are, or might be, sympatric with E. geoffroyi.

How many valid Pleurosicya (Teleostei: Gobiidae) species are known from the Red Sea?

Four species of the gobiid genus Pleurosicya are reported from the Red Sea: P. bilobata, P. mossambica, P. plicata, and P. prognatha. Pleurosicya bilobata is reported as a new record for the Red Sea based on underwater photographs taken from a seagrass area at Dahab, Egypt, Gulf of Aqaba. A previous Red Sea record of P. micheli, a species occurring from Indonesia to French Polynesia, is based on a misidentification of P. mossambica and can be excluded as the Red Sea species. Phylogenetic COI barcode analysis showed that the genetic distance between Red Sea population and Western Indian Ocean specimens of P. mossambica is low, confirming the synonymy of P. sinaia, described from the Red Sea, with P. mossambica. Furthermore, phylogenetic analysis demonstrated that specimens from the western Pacific under the name P. mossambica are genetically distinct and may represent an undescribed species. Brief descriptions accompanied with underwater photographs are provided for four species of Pleurosicya from the Red Sea.

A new species of Trimma of the T. taylori species group (Teleostei: Gobiidae) from the Red Sea, Indian Ocean.

A new species of Trimma is described from the Red Sea along the Saudi Arabian coast. Specimens and/or photographs of this species are available from the Egyptian Red Sea to Eritrea. These specimens, formerly identified as T. taylori, differ from all other samples from the Indo-Pacific currently identified as T. taylori in having 9 and 89 dorsal- and anal-fin rays respectively (vs. usually 10 and 10 rays), 13 pectoral-fin rays (vs. usually 14 rays), and cycloid scales covering the entire predorsal region from the upper base of the pectoral fin anterior to a convex line posterodorsally to just lateral to the base of the sixth first dorsal-fin spine (vs. predorsal region mostly or entirely covered with ctenoid scales). In addition, specimens from the Red Sea form a monophyletic lineage in a Maximum Likelihood analysis of the COI gene. In this tree, the new species is the sister group to a clade composed of three lineages. One is composed of specimens from the Maldives, which is the sister group of a single available specimen from the Seychelles. These two together are the sister group of specimens of a widespread western Pacific clade.

A new species of Fusigobius (Teleostei: Gobiidae) from the Red Sea and Gulf of Aden.

The gobiid species, Fusigobius humerosus sp. nov., is described based on 12 type and 18 non-type specimens collected from the Red Sea and Gulf of Aden. The new species can be distinguished from congeners by a combination of meristic and morphometric characters. The new species was formerly misidentified with F. humeralis: both are characterised by a semitranslucent body; head and body with numerous small dusky orange-yellow spots; a round black spot in humeral region just above base of pectoral fin; and a black spot subequal to pupil diameter at midbase of the caudal fin. However, Fusigobius humerosus sp. nov. differs from F. humeralis by scales on side of nape not extending forward to above posterior margin of preopercle (vs. scales variably extending forward to between above posterior preopercular margin and orbit); first dorsal-fin spine longest (vs. second and third dorsal-fin spines longest); shorter upper jaw; shorter anal-fin spine; and posterior nostril about halfway between orbit and anterior nostril (vs. posterior nostril closer to orbit). The most complete description of the genus Fusigobius is provided. In phylogenetic analyses of publicly available sequences of the barcoding portion of the mitochondrial cytochrome oxidase subunit I (COI) gene, sequences derived from the new species form a separate and well-divergent monophyletic lineage. The resulting COI gene tree further suggests that the new Fusigobius species is phylogenetically most closely related to F. humeralis which forms its sister species in the maximum likelihood tree. Molecular species delimitation of available Fusigobius COI barcodes shows that 19 or 20 hypothetical divergent evolutionary lineages can be deduced depending on the analytical approach (ABGD = 19 and bPTP = 20), indicating a potentially higher taxonomic richness than the presently acknowledged 11 valid species. However, the assignment of available species names for some lineages remains uncertain, highlighting the need for an additional integrative taxonomic research on this genus.

Parrotfishes (Teleostei: Labridae: Scarini) of the Socotra Archipelago: Diversity and distributional biogeography, including a range extension of Scarus zufar Randall & Hoover, 1995.

An updated account of the diversity of parrotfishes from the Socotra Archipelago is provided. Fourteen species are positively recorded based on underwater observations, photography and collections, including confirmations of three species which were previously only tentatively recorded: Scarus falcipinnis(Playfair, 1868), Scarus scaber Valenciennes, 1840 and Scarus tricolorBleeker, 1847. The distribution of Scarus zufar Randall & Hoover, 1995, previously known only from coastal waters of southern Oman, Pakistan and Bangladesh, is extended to the Archipelago, with Abd al-Kuri Island representing the westernmost edge of its known range. Visual records of three additional species are yet to be documented. With 1417species the Archipelago approximates the modal richness range of 1518 species for Arabian ecoregions. A species account, accompanied by photographs, provides distinctive characters, distribution details in the Arabian region, and general remarks for each species. The distributional biogeography of the family pertinent to the Socotra Archipelago and the Arabian region is analysed in the context of the Western Indian Ocean. Three main Arabian units are identified: A Red Sea unit spans the combined Red Sea ecoregions and the western Gulf of Aden; a Socotra unit covers south-eastern Arabia including the Archipelago, the eastern Gulf of Aden and southern Oman; and a Gulf unit combines the Arabian/Persian Gulf, the Gulf of Oman, and putatively central Oman. These units form a discrete pan-Arabian cluster within the wider Western Indian Ocean. The Socotra unit resembles more strongly the Gulf unit than the Red Sea unit. Parrotfishes thus contrast overall distributional patterns of reef fishes in Arabia.

Biogeography of the coastal fishes of the Socotra Archipelago: Challenging current ecoregional concepts.

The Socotra Archipelago, located in the eastern Gulf of Aden, has a unique marine environment, which combines tropical and 'pseudo-temperate' elements. An updated species inventory recently considered its coastal fish diversity the highest among Arabian ecoregions, necessitating to re-assess the ichthyogeographic position of the island group. The main aim of this study is to describe the distributional biogeography of its coastal fish fauna in relation to contemporary ichthyogeographic and ecoregional concepts. Inferences are drawn with regard to the marine biogeographic arrangement and ecoregional partitioning of the Arabian region. The main datasets comprise eight and twenty selected families including 404 and 898 species, respectively, from Arabian ecoregions. The Socotra Archipelago has close affinities to a putative ecoregion in the eastern Gulf of Aden that extends to southern Oman. It is more closely related to the Arabian Sea coast of Oman than to ecoregions in the Red Sea and a putative ecoregion in the western Gulf of Aden. The Gulf of Aden does not represent a consistent ecoregion in ichthyogeographic terms, because its eastern and western parts are less closely related to one another than to other ecoregions. The Socotra Archipelago and the eastern Gulf of Aden should therefore not be assigned to a joined province with Red Sea ecoregions. The coastal fish faunas of the southern Red Sea have close affinities with those of the western Gulf of Aden. The Arabian/Persian Gulf is least related to the other Arabian ecoregions. The authors posit the Socotra Archipelago as a distinct ecoregion, either on its own or in combination with affiliated mainland areas. This best reflects the ichthyogeographic data and the exceptionally high levels of fish and overall marine diversity. Two alternative ecoregional delineations are proposed, serving as working hypotheses for onward research.

Contributions to the taxonomy of the mugilid genus Chelon Artedi (Teleostei: Mugilidae), with a major review of the status of C. persicus Senou, Randall & Okiyama, 1995.

New data based on multigene phylogenetic analyses using the COI, 16S, and cytb genes and subsequent molecular species delimitation revealed that the mugilid genus Chelon contains 11 species. Of these, two species, Chelon sp. A and Chelon sp. B, remained unidentified in previous studies. While Chelon sp. B seemingly is a close relative to C. dumerili (Steindachner, 1870), no more detailed information were provided for Chelon sp. A which is present along the east coast of South Africa. Genetic analyses performed in this study, revealed that specimens from the Arabian/Persian Gulf and the Red Sea are nested within one genetic lineage alongside Chelon sp. A. Morphological, morphometric, and meristic analyses of specimens from all three areas demonstrated that they belong to Chelon persicus Senou, Randall & Okyiama, 1995. Chelon persicus was originally described in the genus Chelon but was later placed either in the genus Liza or Planiliza. However, results presented herein confirm its placement in Chelon and its distribution range is extended in the Western Indian Ocean from the type locality (Arabian/Persian Gulf) west to the Red Sea and south to South Africa. Further, the uncertain validity of the recently described Chelon caeruleus Deef, 2018 from the Mediterranean Sea and a previously proposed generic character distinguishing Chelon from Planiliza and Parachelon, the shape of the paired postzygapophyses of the second vertebra, are briefly discussed.

Identification of Mediterranean marine gobies (Actinopterygii: Gobiidae) of the continental shelf from photographs of in situ individuals.

Numerous photographs of live fishes posted by anglers and divers on social media and citizen science databases are important sources of information for ichthyological research. However, validating records that extend the known ecology and bathymetric or geographic distribution of species should rely on a rigorous identification process. The family Gobiidae, with their small size, superficial resemblance among species and high species richness are particularly difficult to identify. Therefore, the identification from photographs of live individuals of Mediterranean marine gobies from the continental shelf was studied. A dichotomous identification key is provided based on photographs of live individuals, allowing positive identification of 41 out of the 66 species reviewed in this publication. Then, for all 66 species we provide a brief description of important characters, which can be used for provisional identification for those species that could not be positively identified using the key. Pending further progress in identification of live individuals, we suggest that records extending the known geographic and ecological species distribution be taken into account only if they could be validated using the dichotomous identification key.

The taxonomic identity of the monocle bream Scolopsis vosmeri species complex (Perciformes: Nemipteridae), with comments on molecular phylogenetic relationships within the genus Scolopsis.

The monocle bream Scolopsis vosmeri species complex is revised. Three species in the complex are recognized: Scolopsis vosmeri (Bloch, 1792), widespread in the Indo-West Pacific, from the northern Indian Ocean (Pakistan, western India, Sri Lanka, Bay of Bengal, and the Andaman Sea, but not recorded from the Red Sea or Arabian Gulf, east African coast or Madagascar) to western Indonesia and Borneo; S. japonica (Bloch, 1793), restricted to the western Pacific Ocean from western Indonesia and north-western Australia east to the Philippines and north to southern Japan; and S. curite Cuvier, 1815, widespread from the western to the eastern Indian Ocean, including the Red Sea and Arabian Gulf. All three species are similar morphologically, and have been confused taxonomically, but phylogenetic analysis of the COI barcoding region shows they are evolutionarily divergent. The three species are redescribed in detail and characters found to distinguish them. Scolopsis vosmeri is easily distinguished from S. japonica and S. curite in having a white band along the side of the body; having a black spot on most body scales (versus greenish yellow spot in S. japonica and S. curite); in lacking a distinct black spot (sometimes a small and faint spot present) on the upper pectoral-fin base (versus small black wedge-shaped spot present in S. japonica and S. curite); caudal peduncle whitish in live individuals (versus caudal peduncle usually yellowish in S. japonica and S. curite); and pelvic and anal fins crimson to orange-red (versus yellow in S. japonica and S. curite). Scolopsis japonica and S. curite are indistinguishable by color pattern but differ in the degree of spination on the preopercular margin. Neotypes are designated for Scolopsis japonica and S. curite. Nomenclatural problems, including validity of the genus Scolopsis, are discussed. We regard Scolopsis curite Cuvier, 1815 as a valid binomial name and thus the type species of Scolopsis Cuvier, 1814 by subsequent monotypy.

Flying fishes (Beloniformes: Exocoetidae) of the Socotra Archipelago with comments on status of Exocoetus socotranus Steindachner.

A checklist of the flying fishes found in the waters off Socotra Archipelago, northwestern part of the Indian Ocean, is provided based on published and original data. Thirteen species from five genera occur in the study area, and four more species found nearby. Keys for the species identification are provided. The type specimen of Exocoetus socotranus Steindachner, 1902 was examined and is determined to be a junior synonym of Cypselurus naresii (Günther, 1889).

A new species of Hetereleotris (Teleostei: Gobiidae) from the Socotra Archipelago (north-western Indian Ocean), a rare case of a hole-associated adaptation in gobiid fishes.

A new cryptobenthic gobiid species Hetereleotris nasoramosa sp. nov. is described based on the holotype and five paratypes collected from the north-eastern part of Socotra Island, Arabian Sea, from moderately large pieces of coral rocks with holes at depths of 811 m. Molecular phylogenetic analysis placed the new species within the genus Hetereleotris. Hetereleotris nasoramosa sp. nov., differs from all species of Hetereleotris in having developed tentacles extending from each anterior and posterior nostril and five transverse suborbital papillae rows (instead four or six in other species). The new species superficially resembles the recently described Red Sea endemic species Cerogobius petrophilus by having forward-set, elevated eyes, a short snout, a moderately large mouth, a relatively deep and short caudal peduncle, and developed tentacles on the head, but differs from it by the same characters of developed tentacles extending from each anterior and posterior nostril and five transverse suborbital papillae rows as from other Hetereleotris species. Both species also share a specific habitat preference for tight holes in rock covered by micro-algae. A full description of the species is provided as well as a revised key to the species of Hetereleotris.

Notes on batoid fishes of the Socotra Archipelago (north-western Indian Ocean), with four new records.

The species composition of batoid fishes from coastal waters of the Socotra Archipelago is reviewed, with confirmed records of the wedgefish Rhynchobatus djiddensis (Forsskål, 1775) and four new records of sharkrays, wedgefishes, and guitarfishes based on collected specimens, including one species from Abd al-Kuri Island, Rhina ancylostoma Bloch Schneider, 1801 (Rhinidae), and three species from the main island Socotra, Acroteriobatus salalah (Randall Compagno, 1995) and Rhinobatos punctifer Compagno Randall, 1987 (Rhinobatidae), and Rhynchobatus australiae Whitley, 1939 (Rhinidae). Among the new records for the Socotra Archipelago, R. australiae represents the first verified record for the Arabian region. In addition, records of four stingray species (Dasyatidae) are verified based on underwater observations accompanied with photographs. All recorded batoid fishes are commercial species caught in the local small-scale fishery. Information on the identification and distribution of each species is provided.

Review of the cardinalfishes of the genus Cercamia (Percomorpha: Apogonidae) of the Red Sea and Indian Ocean with descriptions of three new species.

The representatives of Cercamia from the Indian Ocean including Red Sea are reviewed and three new species are described: Cercamia spio n. sp., formerly known as C. eremia (Allen, 1987), is described from 14 specimens, 1733 mm SL, collected in 1015 meters from northern (Duba) to central (Jeddah) Saudi Arabia and from Jezirat Faraun, Egypt. It also has been photographed from the Gulf of Aqaba (Dahab, Egypt) and El Quseir (Mangrove Bay, Egypt). The new species is distinguished from other Indian Ocean Cercamia in having fewer developed gill rakers on lower limb (usually 11 versus usually 1213) and fewer anal-fin rays (11 versus usually 1213). Another new species, Cercamia laamu, n. sp., is described only from the Maldives and Chagos Archipelago based on five specimens 16.030.5 mm SL. It differs from all Indian Ocean Cercamia in having more greater number of the second dorsal-fin rays (10 versus usually 9), and a translucent body devoid of reddish marks versus small reddish dots and crisscross lines. The third new species, Cercamia mascarene, n. sp., is described from 40 specimens 1936 mm SL, from Rodrigues Island, Mauritius. It differs from Cercamia eremia in having a greater number of developed gill rakers on the lower limb of the first gill arch (usually 13 versus usually 12). Free neuromasts and cephalic pores are illustrated for Cercamia mascarene and free neuromasts on the body and caudal fin are illustrated for Japanese specimens of C. cf. eremia. New diagnoses are provided for Cercamia cladara, the type species of the genus, and C. eremia. A map of collection locations for species of Cercamia is presented to show the breath of known occurrences in the Red Sea and Indian Ocean. A new morphologic diagnosis is provided for Cercamia. A phylogenetic analysis of the barcoding portion of the mitochondrial COI gene, including all available sequences from members of the genus Cercamia, displays a much higher species diversity than expected, with high levels of divergence among recognized and undescribed species. A key to the described Indian Ocean species is provided.

A new species of the cardinalfish genus Apogon (Teleostei, Apogonidae) from the southern Red Sea and Indian Ocean with comments on phylogenetic relationships within the Apogonini.

Apogon fugax is described as a new species of cardinalfishes based on a specimen trawled off Jizan (Saudi Arabia), southern Red Sea, at a depth of 60-67 m; two specimens trawled off southwest of Ayeyarwady Delta, Myanmar, at 54-129 m; and two specimens trawled off Western Australia at 166 m. The new species shares characters with the modified 'talboti look-alikes' species group (i.e., A. caudicinctus, A. dianthus and A. soloriens) as well as A. rubrifuscus and A. deetsie (both previously also assigned to the latter species group) in having two supraneurals, 12 pectoral-fin rays (13 rays in A. soloriens), and an enlarged, membranous, ventral preopercular edge. Molecular phylogenetic analysis of the apogonid tribe Apogonini, however, revealed that A. fugax n. sp. and its most closely related congeners, A. deetsie and A. rubrifuscus, form a separate phylogenetic clade unrelated to that formed by the 'talboti look-alikes' species group that is part of the A. unicolor species group. Apogon fugax n. sp. is distinguished from the species of the 'talboti look-alikes' species group, A. deetsie and A. rubrifuscus, in having a large head (2.2-2.4 in SL versus 2.4-2.8 in SL), longer first dorsal-fin spine (1.7-2.0 versus 2.7-4.0 in length of the second spine), and in their gill rakers count (developed gill rakers on the first gill arch 11-12 versus 8-9 in A. soloriens and 13-20 in the other four species).