Pterygotrigla Waite 1899

Richards, William J. & Yato, Takuji, 2012, The tropical species of the subgenus Pterygotrigla (Pisces: Triglidae: Pterygotrigla) with description of a new species, Zootaxa 3484, pp. 53-64 : 54-56

Subgenus Pterygotrigla Waite 1899

Diagnosis. Nasal spine absent (present in Parapterygotrigla ), opercular spine small extending slightly past or just to opercular margin (very long in Otohime ), antrorse rostral spine absent; nuchal spine strong extending past D1 fin plate, cleithral spine prominent, often long and strong (8–22% SL), P1 fin long (25–55% SL). Body scales lacking cteni, lateral line scales simple tubes. No spines present along base of D2 fin.

Species. The southern temperate species include Pterygotrigla polyommata (Richardson) from southern Australia from the vicinity of Sydney, New South Wales south around Tasmania and west to Perth, Western Australia and off the northern coast of North Island, New Zealand. Ranging in depth from 18–300m with specimens <125mm SL found at depths less than 55m; P. pauli Hardy from the Tasman Sea at the Challenger Plateau west of New Zealand, Saumarez Reef off Queensland, Australia, and south of Norfolk Island at depths ranging from 333 to 630m; P. p i c t a (Günther) found off the coast of Chile near Isla Juan Fernandez, Isla San Felix, and neighboring guyots of the Sala y Gomez and Nazca Ridges in depths of 160–350 m, at Easter Island (see Randall et al. 2005), and westward to the Norfolk Ridge, New Caledonia (see del Cerro and Lloris 1997). Pterygotrigla picta , as well as all of the proceeding species, maybe found also at other seamounts and ridges. Pterygotrigla andertoni Waite is found around both the North and South Islands of New Zealand (with fewer specimens collected around the South Island) and eastward on the Challenger Plateau, but it has not been taken around the Chatham Islands ( Roberts 1991). In Australian waters it occurs from Saumarez Reef (Queensland) to Bass Strait. Gomon et al. (1994) report it also occurring from the center of the Great Australian Bight west to Fremantle (Western Australia), but we have not seen specimens from that area and Gomon (pers. comm.) was unable to verify it. The relationships of these species await biochemical/genetic studies especially concerning the validity of P. andertoni as it may be conspecific with P. p i c t a.

The tropical species that are treated in this study include P. ryukyuensis Kamohara that occurs from Japan southward through the South China Sea, Indonesia, and northwestern Australia. Pterygotrigla guezei Fourmanoir is found around Mauritius and Reunion islands and the Mozambique Channel off western Madagascar in the western Indian Ocean. Pterygotrigla saumarez Last and Richards is found off Queensland, Australia. Pterygotrigla gomoni Last and Richards is found off Western Australia. Finally, a new species, Pterygotrigla cajorarori , with extreme hyperostosis is described herein and recorded from the Philippines, Japan, Indonesia, and Saumarez Reef, Australia.

All of the tropical species are rare in collections as they occur in deep water> 300 m and few individuals been collected. Of the five species treated here, we examiined 36 specimens (including the eight type specimens of P. gomoni and P. s a u m a re z) for this study. There is little variation in fin ray counts in the tropical species ( Table 1 ) with most specimens having 8 first dorsal fin spines, 11 second dorsal fin rays, 12 anal fin rays, and 12 + 3 pectoral fin rays ( P. guezei has 11+3). Gill rakers are few in number (generally 6–7 plus rudiments) and are short (<2 % SL) (see Tables 2 and 3). All of the species are very similar in shape, especially P. ryukyuensis , P. guezei , and P. cajoraror i sp. nov. with inter-species variation in pectoral fin length, cleithral spine length, interorbital width, and cheek height occuring only between P. saumarez and P. gomoni . Squamation features ( Table 4) are of great value for identification purposes. All of our specimens were faded and little could be determined about color pattern. Pterygotrigla saumarez has black pigment around the nares, but black pigmentation in the first dorsal fin or the pigmentation pattern of the inner surface of the pectoral fin (sometimes quite diagnostic in fresh or living specimens) could not be discerned. Hyperostosis was noted in P. cajorarori sp. nov. and there were some indications that this condition occurs also in P. ryukyuensis . Hyperostosis has been documented only in one triglid ( Prionotus stephanophrys ) Smith-Vaniz et al. (1995). Hyperostosis is characterized by swelling of bones and seems to be limited to a few species across a broad spectrum of families ( Smith-Vaniz and Carpenter 2007). It is described in the respective species accounts.

Relationships of the species within the subgenus are difficult to assess as the morphological characters are very similar for all species. It is unclear if loss of a character represents character reversal. The combination of absence of the nasal spine and short opercular spine separates the subgenus Pterygotrigla from the other subgenera. The temperate species ( P. polyommata , P. p i c t a / andertoni , and P. pauli ) all lack scales on the nape and pre-pectoral area, but a few may have small patches of scales on the breast and interpelvic area. They all have 12+3 P1 rays thus the tropical P. guezei is unique with 11+3. A few temperate specimens have 11 connected P1 rays. The temperate species generally have 12 D2 rays and a greater number of gill rakers of average greater lengths than the tropical species ( Tables 1 –3). Pterygotrigla guezei and the hyperostotic new species, P. cajorarori , are the only ones with extensive squamation on the nape. Ptreygotrigla gomoni is unique in possesing prepectoral squamation plus having a rather short cleithral spine. Pterygotrigla saumarez has a long P1 fin, but it is within the temperate-species P1 length range. There is a need for more material over wider size ranges together with color photographs, especially of the inner surface of the P1 fin, and tissue samples for biochemical analyses. Pterygotrigla ryukyiensis may be a species complex as there are wide morphological variations. These species with the exception of P. polyommata are of no fishery importance and they occur at great depths that are very expensive to sample.

Fin Rays

Key to the tropical species of Pterygotrigla (Pterygotrigla) 1

1a. Nape lacking scales.................................................................................... 2

1b. Nape with scales...................................................................................... 4

2a. No black pigment on or around nares, pectoral fin moderate (<40% SL).......................................... 3

2b. Black pigment on nares, pectoral fin long (>40% SL)................................................ P. saumarez

3a. Prepectoral area lacking scales, cleithral spine long (16–29% SL).................................... P. ryukyuensis

3b. Prepectoral area with small patch of scales, cleithral spine short (9–11% SL)................................ P. gomoni

4a. No hyperostotic head bones or D1 spines, P1 fin rays 11+3................................................ P. guezei

4a. Hyperostotic bones present on head and D1 fin spines, P1 fin rays 12+3........................... P. cajorarori sp. nov.

1 P. p i c t a / andertoni and P. pauli may occur in and near the tropics, but are easily separable from the tropical species by presence of many dark spots on the dorsal trunk.

Tables

TABLE 1. Frequency distribution of fin rays in the tropical and temperate species of the subgenus Pterygotrigla. Holotype value in boldface.

number of D1 Spines Tropical species specimens 7 8 P. ryukyuensis 16 1 8 P. guezei 5 2 3 P. s a u m a re z 5 1 3	9 7 1	D2 11 12 13 12 4 5 4 1	Anal P1 [phone] 16 5 4 1 4 5
P. gomoni 3 2 P. cajorarori nov. sp. 8 2 5	1 1	3 7 1	3 3 8 8
Temperate species P. p i c t a 13 5 8 P. andertoni 21 5 14 P. pauli 9 2 5	1	1 6 3 17 9	10 2 7 1 18 2 3 10 9 1 7
P. polyommata 20 6 17		1 18 1	1 17 2 18
TABLE 2. Frequency distribution of gill rakers in Holotype value in boldface.	the	tropical and temperate	species of the subgenus Pterygotrigla .
number of Tropical species specimens 4 5 P. ryukyuensis 16 1 P. guezei 5 1 P. s a u m a re z 5		Total Gill Rakers 6 7 8 8 4 2 1 2 1 2 3	9 10 11 12 13 1
P. gomoni 3 P. cajorarori nov. sp. 8 1 Temperate species		1 2 3 3 1
P. p i c t a 7 P. andertoni 12 P. pauli 10		2 1 1 7 1 2	1 1 2 1 3 7
P. polyommata 19		2 2	11 1 3