Paracheilinus amanda, Tea & Walsh, 2023

Tea, Yi-Kai & Walsh, Fenton, 2023, Review of Australian Species of Paracheilinus Fourmanoir (Teleostei: Labridae), with Description of a New Species from the Great Barrier Reef and Coral Sea, Ichthyology & Herpetology 111 (3), pp. 397-415 : 402-409

Paracheilinus amanda , new species

urn:lsid:zoobank.org:act:84FE0313-6FEF-43EC-9DB1-DE52090AB295

Amanda’s Flasher Wrasse

Figures 3 , 4 , 5A 1–A 2 , 6 , 7 ; Tables 1–2

Paracheilinus rubricaudalis (non Randall and Allen, 2003): Allen et al., 2016: 73, fig. 47 (aquarium specimen from Great Barrier Reef; image reproduced here [ Fig. 2 ]); also misidentified as P. rubricaudalis in molecular phylogeny.

Holotype.— QM I.39758, 47.6 mm SL, Harrier Reef, Great Barrier Reef, 15808 0 S, 145841 0 E, 20 m, T. Bennett, 27 October 2013.

Paratypes.— AMS I.50116-001, 44.4 mm SL, Flora Reef, Coral Sea, 16846 0 S, 147846 0 E, 42 m, hand nets, T. Bennett, 2 February 2022 (GenBank accession number OQ605966); WAM P.33973.001, 2, 37.3–43.7 mm SL, Harrier Reef, Great Barrier Reef, 15808 0 S, 145841 0 E, 35–36 m, hand nets, T. Bennett, 1 September 2013 ; ZRC 64175, 2, 32.3–47.6 mm SL, 40–50 m, hand nets, G. Gaylan, J. M. Nugas, and J. Genoso, off Hula, southern Papua New Guinea, Coral Sea, 28 March 2023 .

Diagnosis.— Dorsal-fin rays IX,11; anal-fin rays III,9; pectoral-fin rays 14; pelvic-fin rays I,5; pored lateral-line scales 14– 17 þ 5–7 ¼ 19–24; gill rakers 5–6 þ 11–12 ¼ 16–18; body depth 3.2–3.8 in SL; head length (HL) 3.1–3.3 in SL; snout length 4.0 in HL; orbit diameter 3.0– 3.6 in HL; interorbital width 3.0– 3.4 in HL; least depth of caudal peduncle 2.3 in HL; caudal peduncle length 1.7–2.3 in HL; TP males with one elongate, red filamentous dorsal-fin ray, longest dorsal-fin soft ray 2.1–5.5 in SL; pelvic fin length 2.0– 2.8 in HL; caudal fin of TP males round without filamentous lobes; body with stripe pattern B; basal third of anal fin bright yellow, remaining distal two-thirds orange red, demarcation of both colors with incomplete row of blue spots (usually completely absent).

Description.— Dorsal-fin rays IX,11; anal-fin rays III,9; last dorsal- and anal-fin rays split to base; pectoral-fin rays 14, upper two unbranched; pelvic-fin rays I,5; principal caudal-fin rays 7 þ 6, uppermost and lowermost unbranched (lowermost principal caudal-fin ray aberrantly branched in AMS I.50116-001; Fig. 4 ); upper procurrent caudal-fin rays 5; lower procurrent caudal-fin rays 5 (4–5); lateral line interrupted, with dorsoanterior series of pored scales 17 (14–17) and midlateral posterior peduncular series 6 (5–7); first pored scale on posterior peduncular series often pitted; last pored scale on posterior peduncular series enlarged and overlapping hypural crease; scales above lateral line to origin of dorsal fin 2; scales below lateral line to origin of anal fin 6; median predorsal scales 5; median preventral scales 5 (3–6); transverse scale rows on cheek 2; circumpeduncular scales 16 (14–16); gill rakers 6 (5–6) þ 11 (11–12) ¼ 17 (16– 18); vertebrae 9 þ 16 ( Fig. 4 ).

Body depth 3.2 (3.2–3.8) in SL; body width 2.1 (1.9–2.3) in body depth; head length 3.1 (2.8–3.3) in SL; snout length 4.0 (4.0–4.4) in HL; orbit diameter 3.6 (3.0–4.5) in HL; interorbital width 3.4 (3.0–4.5) in HL; least depth of caudal peduncle 2.3 (2.3–2.9) in HL; caudal-peduncle length 1.8 (1.7–2.3) in HL.

Mouth small, oblique, maxilla not reaching vertical at front edge of orbit, upper jaw 4.0 (3.9–6.4) in HL; three pairs of curved canine teeth anteriorly in upper jaw, progressively more laterally projecting, third (posteriormost) pair largest; single pair of canine teeth anteriorly in lower jaw, very strongly curved laterally; side of jaws with single row of small close-set conical teeth; no canine tooth at corner of mouth; no teeth on palate; fleshy flap on side of lower lip; gill rakers short, longest about one-third length of longest gill filaments on first gill arch; posterior nostril an oval opening about 2–3 times larger than cephalic sensory pores, about level with fleshy upper edge of orbit and slightly anterior to vertical at anterior bony rim of orbit; anterior nostril smaller, with a short fleshy rim anterior and slightly ventral to posterior nostril; internarial space about 1.0 in orbit diameter.

Head scaled except for interorbital space, snout, and chin; a row of pointed scales on base of dorsal and anal fins; basal half of caudal fin with large scales; axillary scale of pelvic fin slightly longer than pelvic spine; midventral scaly process of pelvic fins slightly shorter than pelvic spine. Free ventral margin of preopercle extending to vertical at center of orbit, vertical posterior margin to level of lower edge of orbit; exposed bony edge of preopercle smooth without serrations. Origin of dorsal fin above third lateral-line scale, predorsal length 3.2 (2.8–3.2) in SL; dorsal-fin spines progressively longer, first 9.6 (9.2–14.6) in HL, and ninth 2.1 (2.0–2.7) in HL; one to three elongate filamentous segmented rays on posterior dorsal fin in males, bound together by membrane, first longest, 2.1 (1.8–5.7) in SL; origin of anal fin below base of last dorsal-fin spine, preanal length 1.9 (1.7–1.9) in SL; first anal-fin spine 5.1 (4.5–9.6) in HL; second anal-fin spine 3.8 (3.6–5.0) in HL; third anal-fin spine 3.0 (3.0–4.3) in HL; longest anal-fin soft ray 4.2 (3.7–8.1) in SL; caudal fin rounded, 3.6 (3.6–4.6) in SL; pectoral-fin length 1.6 (1.5– 1.7) in HL; pelvic-fin length 2.0 (2.0–2.8) in HL.

Coloration of males in life.— Based on color photographs of specimens when freshly dead, and live individuals photographed in aquaria ( Figs. 3 , 5A 1–A 2 , 7 ): head and body orange to orange brown with body stripes following pattern B; stripes purplish blue to bright neon blue in life; iris bright orange with bright yellow ring around pupil; spinous portion of dorsal fin yellow; posterior soft dorsal fin hyaline overlain with bright metallic blue, sometimes breaking into indistinct spot-bands medially and on distal edge; first two to three interradial membrane spaces (including the filament) bright red; basal third of anal fin bright yellow, remainder distal portion of fin bright orange red, interphase of both colors usually without blue spots, or if present, usually incomplete and towards posterior portion of fin; distalmost edge of anal fin bright blue; caudal fin hyaline with a pair of concentric blue bands following contour of fin, first on basal third, second on outermost edge; pelvic fins reddish hyaline, bright blue on distalmost edge; pectoral fins hyaline.

Coloration of females in life.— Females typical of species in this species complex. Head and body orange to orange brown with body stripes following pattern B; stripes purplish blue to neon blue in life. Median fins yellow hyaline with indistinct blue markings.

Color in preservation.— Uniformly pale tan, except body stripe pattern now dark tan. All fins translucent hyaline. Segmented fin rays on median fins in the largest specimen (47.6 mm SL holotype) purple.

Habitat and distribution.— Paracheilinus amanda is known from Harrier Reef in the northern Great Barrier Reefs, as well as Flora, Holmes, and Osprey Reefs in the Coral Sea. It is also known from specimens collected off Taurama and Hula in southern Papua New Guinea, along the north-western margin of the Coral Sea. The identity and collection locality of the specimen of P. rubricaudalis used in the molecular phylogeny of Allen et al. (2016) is erroneous. The specimen is P. amanda , collected from Harrier Reef, not Ribbon Reef, alongside the WAM paratypes (WAM P.33973.001). The species frequents habitat typical of the genus, consisting of low-lying rubble pans between 20 to 50 m. It is replaced by the closely related P. carpenteri in Japan, Philippines, Brunei, eastern Sulawesi, and Palau, P. flavianalis in Indonesia (Bali eastwards in the Lesser Sunda Islands and the Moluccas), Timor Leste, West Papua, and north-western Australia, P. mccoskeri in the Indian Ocean, and P. rubricaudalis in wider Melanesia (northern Papua New Guinea, the Solomon Islands, Fiji, and Vanuatu).

Etymology.— The species is named in honor of Amanda Hay, ichthyology collections manager at the Australian Museum, Sydney. With over 25 years of experience in ichthyological collections and research, she has not only contributed significantly towards the study of Australasian fishes, but also supported and assisted the research endeavors of many ichthyologists of all career stages working at the Australian Museum. The name amanda is treated as a noun in apposition.

Comparisons and phylogenetic interpretation.— Paracheilinus amanda most closely resembles P. carpenteri , P. flavianalis , P. mccoskeri , and P. rubricaudalis ( Fig. 5 ). The five species form a complex of largely allopatric species united in sharing stripe pattern B, hereafter referred to as the P. mccoskeri complex. Except for P. carpenteri and P. flavianalis , members of the P. mccoskeri complex typically possess a single dorsal-fin filament through prolongation of the anteriormost 1–3 segmented rays. Since all five species possess overlapping morphometric and meristic characters, separation of species is most reliable through comparison of live coloration of TP males, which typically involves a combination of coloration details of the dorsal filament(s), posterior dorsal fin, and anal fin. As with many species of Paracheilinus , intraspecific variation is typically very high, although some trends are evident within each species. This variation is further exacerbated by the proclivity for hybridization displayed in several species. As such, it is possible to encounter individuals that depart from the following character summaries.

In P. amanda ( Figs. 3 , 5A 1–A 2 , 7 ), the anal fin is sharply bicolored, with the basal third yellow and the distal region bright orange red. The interphase of both colors on the anal fin is incompletely lined with bright blue spots (spots usually absent entirely). The dorsal fin is always with a single red filament, and the posterior portion of the dorsal fin is extensively decorated in metallic blue. The segmented rays of the median fins are deep purplish red in life, turning purple in alcohol.

In P. carpenteri ( Fig. 5B ), the anal fin is usually sharply bicolored (as with P. amanda ) and usually, but not always, with a complete series of blue spots along the colored interphase. The dorsal fin is ornamented with 2–6 (usually 3–4) filaments that vary in color from yellow to red. The bases of the caudal fin and posterior dorsal fin are often blackened (the latter with an elongate black blotch). In addition to displaying the typical assortment of stripes in pattern B, there is always an additional short stripe behind the pectoral fin. Large males can sometimes have the body stripes broken and somewhat reticulate.

In the highly variable P. flavianalis ( Figs. 5C , 7 , 8 , 9 ), the anal fin is never sharply bicolored, and is almost always uniformly yellow or orangey yellow (very rarely it may be washed with red near the distal edge, but this demarcation is always suffused; Fig. 8B ). There is usually, but not always, a complete series of blue spots (cf individuals in Figs. 5C , 7 , 8B, D ) on the anal fin. The dorsal fin is ornamented with 1– 4 (usually one) red filament(s). The segmented rays of the median fins turn purple in alcohol.

In P. mccoskeri ( Fig. 5D ), the anal fin is usually, but not always, sharply bicolored (as with P. amanda and P. carpenteri ), with the basal third yellow and the distal region bright orange red. Occasionally, individuals may have entirely yellow or red anal fins (the latter phenotype is more common in the western Indian Ocean). The interphase of both colors on the anal fin is usually, but not always, completely lined with bright blue spots. The dorsal fin is always with a single yellow filament, and the posterior dorsal fin is richly decorated in metallic blue on the distal edge.

In P. rubricaudalis ( Figs. 5E , 7 ), the interradial membranes of the anal fin are a rich orange yellow that contrast strongly with the bright purplish red segmented rays, giving the appearance of deep serrations on the fin. The anal fin is almost always without blue spots. The dorsal fin is always with a single yellow or red filament, and the posterior dorsal fin is bright red without metallic blue markings. The caudal fin is bright red and with the usual concentric bands attenuated or completely absent.

Among members of the P. mccoskeri complex, P. rubricaudalis , P. amanda , and P. flavianalis share the unusual property of having the segmented rays on their median fins turning purple in alcohol ( Fig. 7 ). In contrast, the rays of P. mccoskeri and P. carpenteri are either translucent, or in large individuals, weakly blue green, in preservation. The unusual quality of purple fin rays and other osseous elements was briefly reviewed by Tea et al. (2022a) for species of Cirrhilabrus , but the condition has not been extensively reviewed for Paracheilinus and other labrid taxa. Several other species of Paracheilinus develop purpling of radial elements in alcohol (see Allen et al., 2016), including P. filamentosus (see below). Character summaries for all species of the P. mccoskeri complex are presented in Table 2.

Molecular phylogenetic analyses of mitochondrial COI recover the P. mccoskeri complex as monophyletic, suggesting that pattern B is synapomorphic for this complex and apomorphic within Paracheilinus ( Fig. 6A ). Paracheilinus amanda , P. flavianalis , and P. rubricaudalis form a monophyletic lineage within the P. mccoskeri complex, with the three sharing successive sister relationships to P. carpenteri and P. mccoskeri ( Fig. 6A ). This relationship is supported by a single morphological character (i.e., purpling of radial elements) and is mostly congruent to those described in Allen et al. (2016), except that in their study, P. rubricaudalis was not included in the analyses; the P. rubricaudalis in Allen et al. (2016) is P. amanda (GenBank accession number KT253628).

While the haplotype diversity for each species corresponds well with species-specific coloration pattern and geographical distribution ( Fig. 6B ), phylogenetic resolution based on mitochondrial COI was unsatisfactory for the lineage comprising P. amanda , P. rubricaudalis , and P. flavianalis . Paracheilinus amanda and P. rubricaudalis were recovered as monophyletic sister lineages, but the relationship of P. flavianalis could not be resolved due to low sequence variability in mitochondrial COI. This scenario is not uncommon for groups of coral reef fishes where sexual selection favors female mate choice and male coloration, leading to incongruent signals in morphological and molecular data, or those that have speciated only very recently ( Victor and Randall, 2014; Hench et al., 2019). Pairwise comparison of mitochondrial COI reveals a genetic distance of 1–1.2% (uncorrected p -distance) between P. amanda and P. rubricaudalis , and between P. amanda and P. flavianalis . Genetic distances between P. rubricaudalis and P. flavianalis were less than 1%, suggesting that separation of both species occurred only very recently. All three species are allopatric ( Fig. 6C ). Notwithstanding the lack of phylogenetic resolution, P. amanda is at the very least distinct from all congeneric species on the basis of morphology and molecular sequence data.

Remarks.— The paratypes of the new species consist mostly of non-TP males, which may account for the larger variation in dorsal-fin filament lengths when compared with other members of its species complex (17.6–54.4% SL vs. 27.8–50.3% SL in our examined specimens of P. flavianalis ; and 45.8–64.1% SL in our examined specimens of P. rubricaudalis ). Live photographs of TP males and morphometric data from the two TP males in the type series ( Figs. 3 , 5A 1 , 5A 2 , 7 ), however, show proportionately longer dorsal-fin filaments in P. amanda compared to lengths typically displayed by related species. The width of the dorsal-fin filament appears to be broadest in P. amanda , consisting of three segmented rays (vs. one to two) at the base of the filament in all specimens examined in the type series. More comparative material is needed to determine if this character is restricted to this species.

The AMS paratype of P. amanda (AMS I.50116-001) has the lowermost principal caudal-fin ray deeply bifurcate and branched close to the base ( Fig. 4 ). An X-ray of the specimen suggests that this branching is aberrant and likely a result of improper healing of an injury. The ray immediately above appears to have been injured in the same position.

Figures

FIG. 3. Paracheilinus amanda, new species, aquarium specimen from Harrier Reef, the Great Barrier Reef. Specimen not retained. Photograph by K. Endoh.

FIG. 4. X-ray of Paracheilinus amanda, new species, AMS I.50116-001, paratype, showing aberrant branching of lowermost principal caudal ray.

FIG. 5. A selection of Paracheilinus in life. (A1) P. amanda, new species, ZRC 64175, male paratype, 47.6 mm SL, off Hula, southern Papua New Guinea, Coral Sea; (A2) P. amanda, new species, underwater photograph from Osprey Reef, Coral Sea; (B) P. carpenteri, underwater photograph from Mabini, Batangas, Philippines. Note the darkened posterior dorsal- and caudal-fin bases and the presence of a second stripe behind the pectoral fin; (C) P. flavianalis, underwater photograph from Bali, Indonesia; (D) P. mccoskeri, underwater photograph from Khao Lak, Thailand; (E) P. rubricaudalis, underwater photograph from Mborokua, Solomon Islands. Note the reduced markings on caudal fin. Photographs by H. H. Tan (A1); T. Yamazumi (A2); T. Cameron (B); V. Chalias (C); T. Kawamoto (D); and N. DeLoach (E).

FIG. 1. Schematic diagrams illustrating the body stripe pattern in species of Paracheilinus. (A1) Pattern A; (A2) Pattern A’. Note spot-band pattern derived from Pattern A; (B) Pattern B. Note caudal-fin markings, which do not typically vary for species sharing Pattern B; (C) Pattern C. Note “shepherd’s crook” marking at pectoral-fin base. Illustration by J. W. Soong.

FIG. 2. Paracheilinus paineorum (non-Australian species) demonstrating filamentous prolongation of segmented dorsal- and anal-fin rays. In this specimen, nearly all dorsal-fin rays are unbranched. Note that the bifurcation at the tip of the first dorsal filament is not supported by branching of the segmented ray (it appears to be a result of a tear in the surrounding membrane). Note the presence of aberrant anal-fin filaments. Underwater photograph taken in Lembeh Strait, Indonesia, by N. DeLoach.

FIG. 6. (A) Maximum-likelihood phylogenetic relationships for select species of Paracheilinus inferred using mitochondrial COI. Support values at nodes correspond to SH-aLRT and UFBS support values, respectively. Scale bar indicates the number of substitutions per site. Outgroup taxa were pruned from the tree (see Allen et al., 2016). See Data Accessibility for tree file. (B) Median-joining haplotype network inferred using mitochondrial COI. Each circle represents a haplotype, and its size is proportional to its total frequency. Each black crossbar represents a single nucleotide change. (C) Geographical distribution for select species of Paracheilinus. Members of the P. mccoskeri species complex are represented by colored circles. Distribution records for P. carpenteri and P. mccoskeri are not shown in full—the former extends into southern Japan (indicated by the green broken arrow), and the latter extends into the western Indian Ocean (indicated by the purple broken arrow). Bicolored symbols indicate sympatry in that locality. Colored stars indicate distribution records for P. filamentosus and P. nursalim in Australia.

FIG. 7. Paracheilinus amanda, new species (above right), aquarium specimen from Harrier Reef, Great Barrier Reef; P. rubricaudalis (middle right) underwater photograph from Solomon Islands; and P. flavianalis (below right), underwater photograph from Bali. The purpling of median-fin rays in preserved specimens are shown in the lettered insets. (A) Paracheilinus amanda, QM I.39758, holotype; (B–C) Paracheilinus rubricaudalis, WAM P.33979.001; (D) Paracheilinus flavianalis, NTM S.18121-011. Live photographs of P. amanda, P. rubricaudalis, and P. flavianalis by F. Walsh, D. Brown, and K. Nishiyama, respectively. Live specimens not retained. Photographs of preserved specimens by T. Miskiewicz and Y. K. Tea.

FIG. 8. Select individuals of Paracheilinus flavianalis demonstrating variability in the number of dorsal-fin filaments, coloration of anal fin, and spot band pattern on the anal fin. (A) Underwater photograph from Triton Bay, Indonesia; (B) underwater photograph from Wakatobi, Sulawesi, Indonesia; (C–D) underwater photographs from Bali, Indonesia. Photographs by R. Smith (A); J. Castellano (B); W. Osborn (C); and R. H. Kuiter (D).

FIG. 9. Paracheilinus flavianalis, underwater photograph from Hibernia Reef, Timor Sea, north-western shelf of Western Australia. Note sympatric Cirrhilabrus morrisoni and habitat consisting of extensive Halimeda growth. Photograph by G. R. Allen.