Plectranthias nanus Randall 1980: 159
Allen & Steene 1988: 180
Paxton et al. 1989: 507
Allen & Smith-Vaniz 1994: 9
Allen 2000: 87
Allen et al. 2006: 991
Allen & Erdmann 2012: 289
Hobbs et al. 2014a: 194
Hobbs et al. 2014b: 210
Anderson 2018: 31
Parenti & Randall 2020: 28
Review of Australian species of Plectranthias Bleeker and Selenanthias Tanaka (Teleostei: Serranidae: Anthiadinae), with descriptions of four new species
Gill, Anthony C.
Pogonoski, John J.
Moore, Glenn I.
Johnson, Jeffrey W.
Zootaxa
2021
2021-01-26
4918
1
1
116
Anderson 2018: 31
782HJ
Randall
Randall
[151,501,859,886]
Actinopterygii
Serranidae
Plectranthias
Animalia
Perciformes
94
95
Chordata
species
nanus
Figures 3B, 11, 39; Tables 1–16, 24
Common name: Dwarf Perchlet
Plectranthias nanus Randall 1980: 159, fig. 22, tabs 13–14 (type locality: Cocos Island, Guam, Mariana Islands; paratypesfrom Cocos-Keeling and Christmas Islands).— Allen & Steene 1988: 180, fig. 134 (checklist, photo, Christmas Island).— Paxton et al.1989: 507(checklist).— Allen & Smith-Vaniz 1994: 9(checklist, Cocos (Keeling) Islands); Allen 2000: 87(checklist, Christmas Island); Allen et al.2006: 991(checklist).— Allen & Erdmann 2012: 289(diagnosis, photo, Christmas Island).— Hobbs et al.2014a: 194, tab. 1 (checklist, Cocos (Keeling) Islandsand Christmas Island).— Hobbs et al.2014b: 210, tab. 1 (checklist, Cocos (Keeling) Islandsand Christmas Island).— Anderson 2018: 31(checklist). — Parenti & Randall 2020: 28(checklist).
Diagnosis.The following combination of characters distinguishes P. nanusfrom all other congeners: dorsal rays X,13–16; fourth dorsal spine longest; pectoral rays 13–15, rarely 13, all rays unbranched; lateral line incomplete, with 15–21 tubed scales; greatest body depth 29.4–33.3 % SL.
Remarks.A relatively small species (maximum size 39.8 mmSL, Randall 1980), P. nanusis known in Australiafrom the Cocos (Keeling) Islands, Christmas Island, Great Barrier Reef and Coral Sea ( Figure 11). Elsewhere, it ranges widely throughout the Indo-West Pacific, as far west as the Red Sea and as far east as the Pitcairn Islandsand Hawaii ( Randall 1980; Heemstra 1996; Heemstra & Randall 2009). It closely resembles P. longimanusin coloration, and shares with it apomorphic modification of the caudal skeleton (hypurals 1 and 2 undifferentiated, versus autogenous in other studied Plectranthiasspecies; Figure 5). Characters distinguishing the two species are discussed under Remarks for P. longimanus. In their table 1 and key for western Indian Ocean Plectranthias, Heemstra & Randall (2009)gave a count of 15 branched caudal-fin rays for this species. In their account for the species, however, they gave a range of 13–15 branched caudal rays. The latter count range agrees with the original description: “13 to 15, usually 13” ( Randall 1980: 162). All specimens examined by us had 13 (7+6) branched caudal rays.
We add the following new observations: scales with peripheral cteni; vertebrae 10+16; supraneurals 2; predorsal formula 0/0/2/1+1; dorsal pterygiophores in interneural spaces 9–13 1/1/1+1/1/1+1 or 1/1/1+1/1+1/1; no trisegmental pterygiophores associated with dorsal fin; terminal dorsal pterygiophore in interneural space 17–18; no trisegmental pterygiophores associated with anal fin; terminal dorsal pterygiophore in interneural space 5–6; ribs present on vertebrae 3 through 10; epineurals present on vertebrae 1 through 10–12; hypurals 1 and 2 represented by undifferentiated plate, other hypurals and parhypural autogenous; well-developed hypurapophysis on parhypural; epurals 3; single uroneural (posterior uroneural absent); ventral tip of cleithrum with well-developed posteroventral process; proximal tip of first anal-fin pterygiophore near distal tips of parapophyses on vertebra 10. FIGURE 39. Plectranthias nanus, specimens from Holmes Reef, Coral Sea, Australia: A) photo of aquarium specimen (not retained); B) WAM P.28541-039, 25.1 mm SL, preserved. Photos by Y.K. Tea (A) and A.C. Gill (B). Morphometric data are summarised in Table 24.
Material examined. Australia. AMSI.19454-088, 2: 23–24 mmSL (radiographs only), Queensland, Great Barrier Reef, channel between Yongeand Carter Reefs, 14°35′S, 145°36′E, 1–18 m, AMSteam, 11 Nov 1975; AMSI.20430-005, 3: 15.6–22.1 mmSL, Christmas Island, Flying Fish Cove, 5–10 m, G. R. Allen& R.C. Steene, 12 Jun 1978; AMSI.20442-005, 25.8 mmSL, Christmas Island, Rocky Point, 10–12 m, G. R. Allen& R. Steene, 29 May 1978; AMSI.25112-116, 3: 20.4–29.0 mm SL (subsequently cleared and stained), Coral Sea, west edge of Osprey Reef, 0.75 kmnorth of pass, 13°54′S, 146°33′E, 1–15 m, rotenone, AMSparty, 8 Nov 1984; WAMP.28541-039, 7: 16.4–25.1 mmSL, Coral Sea, Holmes Reef, 16°31′S, 147°50′E, 12–14 m, G. R. Allen, 20 Nov 1985; WAMP.29637- 027, 23.9 mmSL, Coral Sea, Lihou Reefand Cays, Georgina Cay, 17°37′S, 151°26′E, 18–29 m, G. R. Allen et al., 12 Nov 1987. French Polynesia. AMSI.21646-036, 3: 23.0– 27.5 mmSL (radiographs only), Society Islands, Moorea, near Irioa Island, 17°S, 149°W, 15–20 m, B. Goldman, 18 Jun 1976. Additional specimens identified for distribution information. Australia. AMSI.22616-035, 26.0 mm SL, Great Barrier Reef, Escape Reef North, 15°49′S, 145°50′E, coral and sand, 5–18 m, AMSteam, 2 Nov 1981; AMSI.22634-006, 31.0 mm SL, Great Barrier Reef, Escape Reef North, 15°49′S, 145°50′E, reef dropoff, 18 m, W.A. Starck, 4 Dec 1981; AMSI.25107-032, 2: 18.0– 23.5 mmSL, Coral Sea, Osprey Reef, west edge dropoff ( 13°56′S, 146°34′E), 10–25 m, AMSteam, 6 Nov 1984; AMSI.28993-016, 5: 17.3–27.5 mmSL, Cocos (Keeling) Islands, west side near Wreck Point, 11°19′S, 96°49′E, G. R. Allen, 23 Fed1989; AMSI.33747-023, 22.5 mmSL, Coral Sea, Boot Reef, 09°58.70′S, 144°42.52′E, coral, sand and rubble, 23–30 m, AMSteam, 27 Jan 1993.
3026471477
AMS
Australia
Great Barrier Reef
10
-14.583333
Carter Reefs
1287
145.6
Yonge
95
96
1
Queensland
3026471349
[1086,1366,1592,1619]
1975-11-11
AMS
Australia
95
96
1
3026471417
AMS
Australia
8
Flying Fish Cove
Christmas Island
95
96
1
3026471357
[1086,1179,1628,1654]
R
Allen
Australia
95
96
1
3026471467
1978-06-12
R
Australia
Steene
95
96
1
3026471469
[221,1092,1664,1691]
AMS
Australia
11
Rocky Point
Christmas Island
95
96
1
3026471506
[1096,1190,1664,1690]
R
Allen
Australia
95
96
1
3026471458
1978-05-29
R
Australia
Steene
95
96
1
3026471399
AMS
Australia
8
-13.9
Osprey Reef
1289
146.55
Coral Sea
95
96
1
3026471529
[903,1174,1736,1763]
1984-11-08
AMS
Australia
95
96
1
3026471485
WAM
Australia
13
-16.516666
Holmes Reef
1282
147.83333
Coral Sea
95
96
1
3026471340
[1001,1253,1772,1799]
1985-11-20
R
Australia
Allen
95
96
1
3026471325
WAM
Australia
Coral Sea
24
-17.616667
Cays
1278
151.43333
Lihou Reef
95
96
1
3026471439
1987-11-12
R
Australia
Allen
95
96
1
3026471329
1976-06-18
AMS
B. Goldman
French Polynesia
Society Islands
18
-17.0
Irioa Island
40174
-149.0
Moorea
95
96
1
3026471370
AMS
Australia
12
-15.816667
Great Barrier Reef
1284
145.83333
Escape Reef North
95
96
1
3026471444
[1094,1365,1952,1979]
1981-11-02
AMS
Australia
95
96
1
3026471430
1981-12-04
AMS
W. A. Starck
Australia
18
96
97
-15.816667
Great Barrier Reef
1284
145.83333
Escape Reef North
95
96
1
3026471432
AMS
Australia
18
-13.933333
Coral Sea
1289
146.56667
Osprey Reef
96
97
1
3026471538
[394,671,187,213]
1984-11-06
AMS
Australia
96
97
1
3026471438
AMS
Australia
-11.316667
Cocos (Keeling) Islands
1295
96.816666
Wreck Point
96
97
1
3026471328
[697,943,223,249]
R
Fed
Australia
Allen
96
97
1
3026471426
AMS
Australia
27
-9.978333
Coral Sea
13
144.70866
Boot Reef
96
97
1
3026471335
[943,1218,259,285]
1993-01-27
AMS
Australia
96
97
1