Nemanthias Smith, 1954

Gill, Anthony C., 2022, Revised definitions of the anthiadine fish genera Mirolabrichthys Herre and Nemanthias Smith, with description of a new genus (Teleostei: Serranidae), Zootaxa 5092 (1), pp. 41-66 : 52-56

Nemanthias Smith

Nemanthias Smith 1954: 4

(masculine; type species Nemanthias carberryi Smith, 1954 , by original designation and monotypy).

Emmelanthias Smith 1955: 342

(masculine; type species Emmelanthias stigmapteron Smith, 1955 (= Nemanthias carberryi Smith, 1954 ), by original designation and monotypy).

Diagnosis. The following synapomorphies support monophyly of the genus:

1. Dorsal fin anteriorly positioned. The dorsal-fin origin of most anthiadines is usually above or slightly behind the vertical through the posterior edge of the opercle. The main (proximal) shaft of the first pterygiophore either reclines posterodorsally or is perpendicular to the body axis ( Fig. 3A, B ). In Nemanthias , the dorsal-fin origin is farther forward, varying from above the midpoint of the preopercle and opercle posterior edges to above the middle of the cheek, depending on species ( Fig. 8 ; Table 2 ). The primary (proximal) shaft of the first dorsalfin pterygiophore is angled distinctly anterodorsally ( Fig. 3C, D ). Similar anterior positioning of the dorsal fin and forward angling of the first dorsal-fin pterygiophore occurs in Odontanthias , some species of Meganthias Randall & Heemstra, 2006 (but not others) and Sacura Jordan & Richardson, 1910 ( Heemstra & Randall 1979; Randall & Heemstra 2006; Gill & Russell 2019); both molecular and morphological evidence suggests these taxa are closely related to each other ( Gill & Russell 2019; Zajonz et al. 2020). It also occurs in some species of the Atlantic/eastern Pacific genera Anthias , Hemanthias Steindachner, 1875 , Pronotogrammus Gill, 1863 and Baldwinella Anderson & Heemstra, 2012 . However, morphological characters and preliminary molecular phylogenies suggest none of these genera is closely related to Nemanthias , and I therefore consider the similar dorsal fin position and pterygiophore orientation to be independently derived.

2. Males with posterior supernumerary spine on first dorsal-fin pterygiophore relatively elongate. Anthiadines typically have three fin spines associated with the first dorsal-fin pterygiophore, two in supernumerary association (first and second spines) and one in serial association (third spine). Typically in males with elongate spines, only the serial spine is elongate, although some species of Baldwinella may have more posterior spines also elongate, and the anterior supernumerary spine is elongate or subequal to other spines in Pseudanthias pictilis ( Randall & Allen, 1978) . In males of Nemanthias species , the posterior supernumerary spine on the first dorsal-fin pterygiophore is relatively elongate and is often produced, filamentous and subequal to or longer than the serial spine ( Fig. 8 ). Clarification of the homology of anterior dorsal-fin spines in the type species, N. carberryi , is provided in Remarks below.

3. High number of circumpeduncle scales. Anthiadines typically have around 12–30 circumpeduncle scales. Nemanthias species are relatively derived in having smaller and more numerous circumpeduncle scales, with counts of 29–36, modally 31 or more, depending on species ( Table 3 ).

In addition, the following combination of characters distinguishes the genus from other anthiadine genera: branched caudal rays 7+6; no papillae on posterior rim of orbit; tubed lateral-line scales 50–64; predorsal length 20–31% SL.

Description. See Tables 1–5 for variation among species. Dorsal-fin rays X–XII,16–18; dorsal-fin origin varying from above midpoint of preopercle and opercle posterior edges to above middle of cheek ( Fig. 8 ); primary shaft of first dorsal-fin pterygiophore angled distinctly anterodorsally; ADPF 3//1+1+1/1/1/1/1/1/1, S//3/1+1/1/1/1/1/1 or S/S/3/1+1/1/1/1/1/1 (= predorsal formula 2//1+1+1, 0//2/1+1 or 0/0/2/1+1; Fig. 3C, D ); dorsal-fin pterygiophores in interneural spaces9–13 1/1+1/1+1/1+1/1+1,1/1+1/1/1+1/1+1,1/1+1/1+1/1/1+1,1/1+1/1+1/1+1/1,1+1/1/1+1/1/1+1, 1+1/1/1+1/1+1/1 or 1+1/1/1+1/1+1/1+1; terminal dorsal-fin pterygiophore in interneural space 18–19; anal-fin rays III,7–8 (usually III,7); terminal anal-fin pterygiophore in interhaemal space 5–6; pectoral-fin rays 18–22, longest few rays bearing serrations ( Fig. 9 ); pelvic-fin rays I,5; caudal-fin rays 9–12+9+8+7–13; branched caudal-fin rays 7+6; no procurrent spur on upper procurrent ray in lower lobe; penultimate procurrent ray in lower lobe not foreshortened (see Johnson 1975, 1983).

Scales relatively small, tubed scales in lateral line 50–64; circumpeduncle scales 29–36; no auxiliary scales on head or body; lower jaw scaled or naked; basal scaled area on dorsal and anal fins either narrow or scales absent; scales with peripheral cteni only ( Roberts 1993).

Greatest body depth 25–39% SL; head length 28–35% SL; orbit diameter 7–12% SL; predorsal length 20–31% SL; preanal length 59–67% SL; prepelvic length 33–37% SL; caudal peduncle depth 12–15% SL.

Anterior part of upper lip of males hypertrophied ( Fig. 8 ); mouth large, oblique, posterior margin of maxilla reaching to point ranging from vertical through posterior edge of pupil to vertical through posterior edge of eye; mouth terminal, becoming inferior in males; supramaxilla absent; premaxilla with 1 or 2 enlarged canines anterolaterally, a band of small conical teeth about 4 or 5 rows wide at symphysis reducing to 1 or 2 rows on sides of jaw, with outer-row teeth much larger, those of posterior half of jaw curved anteriorly; 1 or 2 posterior teeth in band nearest symphysis sometimes enlarged and caniniform, lying almost flat against roof of mouth; dentary with 1 or 2 laterally curved, enlarged canines at front of jaw, followed by band of small conical teeth about 2–4 rows wide reducing to 1 or 2 rows posteriorly, outer-row teeth much larger, those of posterior part of jaw curved anteriorly; anterior third of dentary with 1 or 2 enlarged, posteriorly curved canines outside band of teeth; vomer with either an oval patch of large conical teeth or a small patch of small teeth; palatine with a narrow band of small conical teeth, 2–10 rows wide at widest point; ectopterygoid, endopterygoid, and tongue edentate.

Opercle with three flat spines, uppermost sometimes indistinct and hidden by scales and skin, lowermost below junction with subopercle, middle spine closer to lowermost spine than to uppermost; preopercle finely serrated at angle and on posterior, vertical edge; interopercle and subopercle smooth or with indistinct crenulae; posttemporal smooth or with indistinct serrations or crenulae; posterior rim of orbit without papillae.

Paired pharyngobranchials (pb) 1 through 4 present, pb4 cartilaginous; tooth plates present on pb2 through pb4, tooth plate on pb4 small and autogenous; paired epibranchials (eb) 1 through 4 present; uncinate process on eb1 fan-shaped, broadly rimmed with cartilage, and directed posterodorsally; no tooth plate on eb2; small toothplate on eb3 ( Figs. 5B–C , 6B–C ); paired ceratobranchials (cb) 1 through 5 present; tooth plate on cb5; paired hypobranchials (hb) 1 through 3 present, none with toothplates; median basibranchials (bb) 1 through 4 present, bb4 as cartilage, none with toothplates; gill rakers elongate on anterior/lateral face of first arch, 9–12 on eb1, uppermost at junction with pb1, and 22–29 on cb1 and hb1; shorter club-like rakers or rudiments present on posterior face of eb1, cb1 and hb1, on both anterior and posterior faces of eb2–3, cb2–4 and hb2, and on anterior face of hb3, eb4 and cb5.

Vertebrae 10+16; parapophyses present on first caudal vertebra; epineurals present on vertebrae 1 through 12 or 1 through 15–17; ribs present on vertebrae 3 through 10–11 (usually 10); preural 2 (pu2) and pu3 haemal spines autogenous; no radial cartilages in caudal skeleton anterior to pu3 haemal and neural spines; parhypural and hypurals autogenous; well-developed hypurapophysis on parhypural; single uroneural; 3 epurals; ventral tip of cleithrum with well-developed posteroventral process.

Composition. Nemanthias carberryi Smith, 1954 , Anthias (Mirolabrichthys) bartlettorum Randall & Lubbock, 1981 , Anthias (Mirolabrichthys) bicolor Randall, 1979 , Mirolabrichthys dispar Herre, 1955 , Anthias (Mirolabrichthys) ignitus Randall & Lubbock, 1981 , and Anthias (Mirolabrichthys) regalis Randall & Lubbock, 1981 .

Remarks. All but the type species were originally described either in the genus Anthias , within the subgenus Mirolabrichthys or in the genus Mirolabrichthys , and were later reclassified in Pseudanthias . Smith (1954) erected Nemanthias for N. carberryi , and reported that it had 11 dorsal-fin spines, with the first spine separated from the remaining spines. He later erected Emmelanthias Smith, 1955 , for E. stigmapteron , noting that it resembles Nemanthias in having anteriorly positioned dorsal and pelvic fins, but differs in having 12 rather than 11 dorsal-fin spines ( Smith 1955). Heemstra & Randall (1986) placed E. stigmapteron in synonymy with N. carberryi , and noted that small juveniles have 12 spines, but the first spine is minute and disappears with growth. However, this spine is visible in a 61 mm SL cleared and stained specimen but is tiny and was not apparent prior to clearing and staining ( Fig. 3D ). Randall & Lubbock (1981) noted that N. carberryi is similar to Mirolabrichthys in having males with a hypertrophied upper lip but considered Nemanthias distinct because of the higher number of dorsal-fin spines and in having the first two spines elongate. They therefore overlooked the tiny first spine, and their first two spines are the homologues of the second and third spines (posterior supernumerary and serial spines, respectively) of other anthiadine species. Although the high dorsal-fin spine count has been considered of generic significance, it is here considered an autapomorphy of N. carberryi and therefore silent on relationships to other species. Additional autapomorphies for the species include the deeply incised membrane between the second and third dorsal-fin spines

( Fig. 8C ), absence of supraneurals, preneural position of the first dorsal-fin pterygiophore, and presence of four (versus one) pterygiophores anterior to the third neural spine ( Fig. 3D ). Although the first dorsal-fin pterygiophore is in the typical (for anthiadines) second interneural space in the remaining species of Nemanthias , they resemble N. carberryi in having the pterygiophore angled forward and the dorsal fin origin relatively anteriorly placed (see synapomorphy 1 above).

Gill et al. (2021a) incorporated three of the included species in their analysis of COI sequences, N. carberryi , N. dispar and N. regalis , and retrieved them as a monophyletic group.

Material examined. Nemanthias bartlettorum AMS I. 19218-001 (1W,X, paratype, 43 mm SL); N. bicolor ACG CS 14 (4 CS, 62–79 mm SL), AMS I.18721-001 (1W,X, paratype, 65 mm SL); N. carberryi AMS I. 48957- 001 (1W, CS, 61 mm SL), ZRC 62340 (2W,X, 38.5–40.0 mm SL); N. dispar ACG CS 574 (3 CS, 34–43 mm SL), ACG CS 907 (6 CS, 43–48 mm SL), AMS I.32478-010 (1 CS, 49 mm SL), AMS I.49578-004 (1W, 53.7 mm SL); N. ignitus ACG CS 673 (2 CS, 33–56 mm SL), AMS I.19219-001 (1W,X, paratype, 50 mm SL); N. regalis AMS I. 19220-001 (1W,X, paratype, 42 mm SL).

Figures

FIGURE 3. Predorsal and anterior portion of dorsal fin of cleared and stained specimens.A) Mirolabrichthys tuka, ACG CS532, 47 mm SL; B) Pyronotanthias lori, ACG CS675, 59 mm SL; C) Nemanthias dispar, ACG CS907, 47 mm SL; D) N. carberryi, AMS I.48957-001, 61 mm SL. Photographs are of the right side (digitally reversed) after removal of the pectoral girdle, scales, and skin. Abbreviations: DP, dorsal-fin pterygiophore; DS, dorsal-fin spines; NS, neural spines; SN, supraneurals. Scale bars = 2 mm. Photographs by A.C. Gill.

FIGURE 5. Right side dorsal gill arches in dorsal view of: A) Mirolabrichthys tuka, ACG CS532, 47 mm SL; B) Nemanthias bicolor, ACG CS14, 62 mm SL; C) N. carberryi, AMS I.48957-001, 61 mm SL; D) Pyronotanthias lori, ACG CS675, 59 mm SL.Abbreviations: EB1-4, epibranchials 1-4; LP, levator process; PB1-4, pharyngobranchials 1-4; PB4TP, pharyngobranchial 4 tooth plate; UP, uncinate process. Scale bars = 1 mm. Illustrations by A.C. Gill.

FIGURE 6. Right side dorsal gill arches in ventral view of: A) Mirolabrichthys tuka; B) Nemanthias bicolor; C) N. carberryi; D) Pyronotanthias lori. Specimens, abbreviations, and scale bars as in Fig. 5. Illustrations by A.C. Gill.

FIGURE 8. Male examples of Nemanthias species.A) N. bartlettorum, BPBM 17981, holotype, 54.2 mm SL, Marshall Islands; B) N. bicolor, BPBM 10146, holotype, 99.2 mm SL, Oahu, Hawaii; C) N. carberryi, 54 mm SL, Maldive Islands; D) N. dispar, BPBM 16139, 54 mm SL, Florida Island, Solomon Islands; E) N. ignitus, BPBM 18858, holotype, 58.3 mm SL, North Malé Atoll, Maldive Islands; F) N. regalis, BPBM 12442, holotype, 55.2 mm SL, Fatu Hiva, Marquesas Islands. Arrows indicate second (posterior supernumerary) dorsal-fin spine. Photographs by J.E. Randall.

FIGURE 9. Portion of right side (image reversed) pectoral fin of cleared and stained Nemanthias dispar, ACG CS907, 47 mm SL, showing serrated projections from rays. Scale bar = 0.5 mm. Photograph by A.C. Gill.

Tables

TABLE 3. Summary of selected scalation characters of Mirolabrichthys, Nemanthias and Pyronotanthias species.

Species	Tubed lateral-line	Circumpeduncle	Lower	Auxiliary scales	Dorsal and anal fin
M. evansi	scales 47–50	scales 25–28	jaw scaled	on body present	basal scalation broad
M. pascalus	48–52	25–27	scaled	present	broad
M. tuka	45–49	23–26	scaled	present	broad
N. barlettorum	54–58	29–32	naked	absent	absent
N. bicolor	57–64	31–33	naked	absent	narrow
N. carberryi	50–56	30–32	scaled	absent	narrow
N. dispar	55–63	32–35	scaled	absent	narrow
N. ignitus	53–58	29–33	scaled	absent	narrow
N. regalis	56–62	32–36	naked	absent	absent
P. aurulentus	47–51	25–26	scaled	absent	narrow
P. bimarginatus	37–44	21–24	scaled	absent	broad
P. flavoguttatus	47–52	24–25	scaled	absent	narrow
P. lori	49–52	25–28	scaled	absent	narrow
P. parvirostris	41–44	21–24	scaled	absent	broad
P. privitera	47–52	25–26	scaled	absent	narrow
P. smithvanizi	44–48	23–25	scaled	absent	narrow
P. timanoa	48–56	27–30	scaled	absent	narrow
P. unimarginatus	43	23	scaled	absent	broad