Kyphosus gladius, Knudsen, Steen Wilhelm & Clements, Kendall D., 2013

Knudsen, Steen Wilhelm & Clements, Kendall D., 2013, Kyphosus gladius, a new species of sea chub from Western Australia (Teleostei: Kyphosidae), with comments on Segutilum klunzingeri Whitley, Zootaxa 3599 (1), pp. 1-18 : 4-10

Kyphosus gladius sp. nov.

(Common name: Gladius sea chub or gladius drummer) ( Figure 2–4 , Table 1)

Kyphosus sydneyanus (non McCulloch 1920): Allen 1985: fig. 235 and 237.

Holotype. WAM P.33456-001, 255 mm SL, Canal Rocks, Yallingup Reef, Western Australia, 33°40' S, 114°59' E, 30 May 2010.

Paratypes. 24 specimens. AMS.I 20233-008 (2 specimens), 78–94 mm SL, Canal Rocks, Yallingup Reef, Western Australia, 33°40' S, 115°00' E, 1 Apr 1978; NMV A 30939 -001, 220 mm SL, Canal Rocks, Yallingup Reef, Western Australia, 33°40' S, 114°59' E, 30 May 2010, collected with spear by SWK and KDC; NMV A 30940 , 381 mm SL, Rockingham, Point Peron, Western Australia, 32°16' S, 115°41' E, 29 May 2010, collected with spear by SWK and KDC; NMV A 30939 -002, 205 mm SL, Canal Rocks, Yallingup Reef, Western Australia, 33°40' S, 114°59' E, 30 May 2010, collected with spear by SWK and KDC; WAM P. 20571, 457 mm SL, Denmark, Western Australia, 35°00' S, 117°20' E, unknown catch date; WAM P. 21747, 254 mm SL, Albany, Western Australia, 35°00' S, 117°52' E, unknown catch date; WAM P.27643-010, 76 mm SL, Bunkers Bay, Western Australia, 33°32' S, 115°02' E, 30 Jun 1932; WAM P.30668-001, 286 mm SL, Jurien Bay, Western Australia, 30°18' S, 115°00' E, unknown catch date; WAM P.30705-002, 49 mm SL, Rottnest Island, Western Australia, 32°05' S, 115°35' E, 6 May 1993; WAM P.33455-001 (4 specimens), 389–439 mm SL, Rockingham, Point Peron, Western Australia, 32°16' S, 115°41' E, 29 May 2010, collected with spear by SWK and KDC; WAM P.33456-002 (10 specimens), 207–286 mm SL, Canal Rocks, Yallingup Reef, Western Australia, 33°40' S, 114°59' E, 30 May 2010, collected with spear by SWK and KDC.

Non-type material. SMNS 2673, 238 mm SL, King George Sound, Western Australia, Jun 1879.

Tissue samples. 20 specimens, six not stored, all collected with spear by SWK and KDC. WAM P.33455-001 (2 specimens), 29 May 2010, Perth, Western Australia, 32° 16'S, 113° 41'E, acc. no. KC136475 , KC136440 ; WAM P.33455-001, 29 May 2010, Perth, Western Australia, 32° 16'S, 113° 41'E, acc. no. KC136532 , JX908486 , KC 130503 , KC 130655 ; NMV A 30940 -011, 29 May 2010, Perth, Western Australia, 32° 16'S, 113° 41'E, acc. no. KC136412 , JX908438 , KC 130473 , KC 130662 ; NMV A 30939 -001 and NMV A 30939 -002 (2 specimens), 30 May 2010, Yallingup Reef, Western Australia, 33° 40'S, 114° 59'E, acc. no. KC136501 , KC136371 ; WAM P.33456-002 (7 specimens), 30 May 2010, Yallingup Reef, Western Australia, 33° 40'S, 114° 59'E, acc. no. KC136551 , KC136392 , KC136396 , KC136367 , KC136459 , KC136431 , KC136443 ; WAM P.33456-001 (holotype for K. gladius ), 30 May 2010, Yallingup Reef, Western Australia, 33° 40'S, 114° 59'E, acc. no. KC136460 , JX908393 , KC 130467 , KC 130615 ; no voucher, only tissue sample stored, 12 Jun 2000, Rottnest Island, Western Australia, 32° 00'S, 115° 34'E, acc. no. KC136484 , JX908416 , KC 130512 , KC 130589 ; no voucher, only tissue sample stored, 0 6 Jun 2009, Perth, Western Australia, 32° 16'S, 115° 41'E, acc. no. KC136556 ; no voucher, only tissue sample stored (3 specimens), 0 7 Jun 2009, Perth, Western Australia, 32° 16'S, 115° 41'E, acc. no. KC136490 , KC136379 , KC136567 ; no voucher, only tissue sample stored, 26 May 2010, Abrolhos Islands, Western Australia, 28° 29'S, 113° 44'E, acc. no. KC136561 .

Diagnosis. Distinguished from other species of Kyphosus from the Indian Ocean and the Pacific Ocean by the following combination of characters: body elongate and compressed. Mouth terminal. Silvery line under eye, colour silvery to bluish metallic; operculum with a vertical green bar running down rear of preoperculum; dorsal part of body without dark counter-shading. Caudal peduncle depth, 9.9-11.8% SL; sixth dorsal fin spine length, 8.7–11.9 % SL; body depth, 33.3–41.6 % SL; 15–19 total gill rakers externally, 3–5 gill rakers on upper limb externally, 11–15 gill rakers on lower limb externally; 44–55 pored scales in lateral line, 55–63 scale rows in lateral line with or without pores, 49–57 scale rows in longitudinal row; 11–12 soft dorsal fin rays, 11–12 anal fin rays, 10+16 precaudal- and caudal vertebrae.

Description. Body elongate and relatively compressed (body depth: 33.3–41.6, mean 39.6 % SL), (body width: 12.6–19.3, mean 16.8 %SL). Caudal peduncle longer (18.7–26.5, mean 23.2 % SL) than deep (9.9-11.8, mean 11.0 % SL). Head 22.1–30.5 % SL (mean 25.3 % SL), frontal slope of head not steep, but smoothly pointed ( Figure 2 and 3 A). Interorbital width 10.7–12.3 % SL (mean 11.5 % SL) and with 12–16 scale rows. Eye diameter (4.3–9.4, mean 6.1 % SL) nearly equals snout length (4.5–8.6, mean 6.8 % SL). Eye with yellow iris and silvery line underneath, olive-green horizontal streak stretching from mouth to behind posterior edge of eye. Operculum with green vertical bar running down rear of preoperculum ( Figure 3 and 4 ). Mouth terminal, relatively short premaxilla (5.8–8.4, mean 7.2 % SL). Posterior end of maxilla reaches behind anterior edge of eye to right below centre of pupil. Preorbital region without scales. Teeth in single outer row, all incisor-shaped on both premaxilla and dentary (8–37 and 8–36, respectively). First gill arch with 3–5 (mean 4.2) gill rakers, externally, on upper part of arch and 11–15 (mean 12.5) on lower part of first arch, giving a total of 15–19 (mean 16.7) gill rakers. Dorsal fin with X–XI (mean 10.9) spines and 11–12 (mean 11.9) soft rays. Pectoral fins with 16–19 rays. Pelvic fins with I spine and 5 rays. Spinous part of dorsal fin low (sixth dorsal fin spine: 8.7–11.8, mean 10.9 % SL). Dorsal fin base relatively short (40.8–49.0, 45.8 % SL). Anal fin with III spines, and 11–12 (mean 11.0) soft rays, and soft-rayed part not raised (second anal fin ray length: 5.0–11.4, mean 9.7 % SL). Anal fin base shorter (16.9–20.6, mean 18.5 % SL) than head length. Pectoral fin silvery at base and dusky distally. Pectoral fin length longer (15.3–18.8, mean 17.4 % SL) than width of pectoral fin base (4.6–6.6, mean 5.6 % SL). Pelvic fin as long as pectoral fin (13.4–16.2, mean 15.2 % SL). Caudal fin forked with a notch that can be more or less pronounced (0.4–10.5, mean 6.1 % SL). Ten precaudal vertebrae and 16 caudal vertebrae, with 20–21 dorsal pterygiophores and 12 anal pterygiophores, with first anterior anal pterygiophore in eleventh interhaemal spine space, and only one dorsal pterygiophore in eighteenth dorsal interhaemal spine space. Maximum size: The largest specimen recorded is 457 mm SL, 515 mm TL (WAM P.20571), but specimens well in excess of 520 mm SL observed in the wild.

Colour of live specimens ( Figure 3 and 4 ).—Head and body silvery to bluish-grey (freshly dead specimens with obvious metallic blue colouration), operculum with olive-green vertical bar down rear edge of preoperculum, also with green horizontal streak stretching from mouth back to anterior groove of preoperculum. The body has horizontal rows of scales across the body with a faint greenish-yellowish shine ( Figure 3 A and 3D); however, these rows are not obvious in underwater photos ( Figure 4 ). Fins dusky to blackish, with pigment more pronounced towards edges of fins. Eye with yellow iris. Horizontal silvery line under eye. Green colouring surrounding orbit. Preserved specimens yellowish-brown, vertical bar on operculum and greenish horizontal scale rows disappears or becomes brown and faint in preservation (see Figure 3 B, WAM P.30668-001).

Distribution. Kyphosus gladius sp. nov. appears restricted to Western Australia, and to date has been collected from the Houtman Abrolhos Islands southwards to Cape Naturaliste and down to Albany on the southern coast of Western Australia (28º29’– 35º00’S). Most western record is from Rockingham near Perth, and most easterly record from Albany (113º41’– 117º52’E) ( Figure 1 ). All reports involve depths from 0 to 15 m. It co-occurs with Kyphosus bigibbus , K. cornelii and K. sydneyanus . Examination of museum collections (WAM and AMS) and available underwater photographs suggest that K. gladius sp. nov. is yet to be recorded from South Australia, Victoria, Tasmania and the eastern coast of Australia. However, it is likely that the distribution might extend further eastward from Albany along the coast of the Great Australian Bight. The northernmost records are from a tissue sample and underwater photographs from the Wallabi Group in the Houtman Abrolhos Islands; whether the distribution extends further north is uncertain, although no specimens were observed during fieldwork on Ningaloo Reef. The most southern record is from Albany. The Houtman Abrolhos Islands represent the northern distribution limit for K. sydneyanus in Western Australia, and this may also be the case for K. gladius sp. nov. ( Figure 1 ).

Etymology. The specific name gladius was chosen as the shape of the body resembles the roman gladius sword, which is widest towards the point and tapers towards the hilt. The relatively elongate body and shallow caudal peduncle, along with the metallic-bluish colouration, resembles this roman sword. The genus name Kyphosus is masculine, hence gladius .

Comparison. Kyphosus gladius differs from the sympatric K. cornelii in having a lower number of soft dorsal fin rays (11–12 versus 14–16, respectively), and lacking a white edge to the caudal fin as in K. cornelii . Furthermore, K. gladius has interorbital scale rows (12–16), whereas interorbital scales are absent in K. cornelii .

Kyphosus gladius differs from K. vaigiensis and K. cinerascens in having a lower total gill raker count (15–19 in K. gladius versus 22–30 and 23–32 in K. cinerascens and K. vaigiensis , respectively) ( Sakai & Nakabo 1995, 2006). Furthermore, K. gladius lacks the golden horizontal scale rows along the body seen in K. vaigiensis , and K. gladius lacks the high fourth dorsal soft ray (6.1–12.3 % SL in K. gladius and 8.7–19.1 % SL in K. cinerascens ), or the high second anal fin ray as in K. cinerascens (5.0–11.4 % SL in K. gladius and 10.2–22.3 % SL in K. cinerascens ) ( Sakai & Nakabo 2006).

Kyphosus gladius differs from K. pacificus in having a lower total gill raker count (15–19 versus 20–26) ( Sakai & Nakabo 2004), and by only having one dorsal pterygiophore (two in K. pacificus and in K. vaigiensis ) in the eighteenth dorsal interhaemal spine space. Kyphosus gladius has dusky dorsal, anal, and caudal fins whereas these fins are paler in K. cinerascens , K. pacificus and K. vaigiensis . Kyphosus gladius can resemble both K. bigibbus and K. sydneyanus in having a low gill raker count (18–21 in K. bigibbus , 15–20 in K. sydneyanus and 15–19 in K. gladius ), but K. gladius differs from K. bigibbus in having a lower number of total scales in the lateral lineincluding those without pores—(55–63 in K. gladius , and 61–76 in K. bigibbus ), and in having a lower number of pored scales in the lateral line (44–55 in K. gladius , and 51–60 in K. bigibbus ). Kyphosus gladius has the same arrangement of precaudal vertebrae and caudal vertebrae (10+16) as Kyphosus bigibbus , which in both cases differs from the 11+15 precaudal- and caudal vertebrae seen in K. sydneyanus . This difference in vertebrae means that the most anterior anal pterygiophore inserts in the space between the tenth and eleventh vertebrae in K. gladius and K. bigibbus , but inserts in the space between eleventh and the twelfth vertebrae in K. sydneyanus . The anal fin base in K. gladius is shorter than in K. bigibbus (16.9–20.6 % SL in K. gladius and 18.1–24. % SL in K. bigibbus ), and K. gladius has no dark countershading dorsally but is rather silvery-blue all over the body, whereas K. bigibbus is darker or has a slight olive-green shading in the dorsal scales. The operculum in K. gladius has a vertical olivegreen bar, which is lacking in K. bigibbus . Kyphosus gladius resembles K. sydneyanus in having a low total gill raker count (15–19 in K. gladius and 15–21 in K. sydneyanus ). Kyphosus sydneyanus is also silvery ( Figure 4 ) but has a tendency to have an olive-green countershading on the upper body ( Figure 3 C and 4). Kyphosus sydneyanus can be distinguished from K. gladius underwater by being less elongate and lacking the green vertical bar on the operculum that is present in the latter species. Furthermore, the caudal peduncle depth in K. gladius has a lower range than in K. sydneyanus (9.9–11.8 % SL versus 12.1–15.5 % SL, respectively), and the body depth of K. gladius is less than in K. sydneyanus (33.3–41.6 % SL in K. gladius and 38.8–52.0 % SL in K. sydneyanus ). Furthermore, the frontal slope of the head in K. sydneyanus is generally steeper than in K. gladius , giving the latter a more elongate appearance.

Molecular comparison. Molecular mtDNA and nDNA markers from all 18 recently collected specimens of K. gladius grouped together in a distinct clade distinct from all other species of Kyphosus ( Figure 5 and 7 ). The molecular results from both mtDNA and nDNA indicate that the sister species of K. gladius is the sympatric K. sydneyanus ( Figure 5 and 7 ). Haplotypes of partial mtDNA cyt b are separated from K. sydneyanus by seven mutations ( Figure 7 ), and estimates of Φ ST (0.8338; P<0.001) from cyt b indicates a significant level of separation between K. sydneyanus and K. gladius .

In 10 specimens of K. sydneyanus that were examined by both molecular data and radiograph photos, all had the 11+15 arrangement of vertebrae and were grouped together by similarity in molecular markers. Likewise, for K. gladius a similar pattern was observed, with specimens having 10+16 vertebrae clustering together in molecular variation. This pattern was consistent for the seven specimens of K. gladius that were examined for both molecular markers and radiographs ( Figure 5 and 7 ).

TABLE 1. Counts and measurements of Kyphosus gladius sp. nov., Kyphosus sydneyanus and Kyphosus bigibbus . Values in parentheses indicate mean and standard deviation.

Kyphosus gladius sp. nov. Kyphosus sydneyanus Kyphosus bigibbus

Range of character, for Range of character, for Range of character, for

specimens examined, including specimens examined, including specimens examined, including holotype, paratypes and non holotype, paratypes and non holotype, paratypes and non type. n type. n type. n ……continued on the next page TABLE 1. (continued) Remarks. At Rottnest Island, where both K. gladius and K. sydneyanus were abundant, the two species were generally observed in discrete conspecific schools. The individuals in these schools became mixed when circling the observer, hence the heterospecific associations seen in Figure 4 . In fact, at Rottnest Island, K. sydneyanus was observed more frequently with K. bigibbus than K. gladius . At the Wallabi Group in the Houtman Abrolhos Islands, where K. gladius appeared rare, individuals of this species were schooling with the much more common K. sydneyanus . The distribution of K. gladius is likely to extend further eastwards along the Great Australian Bight, however, without the ability to obtain further material from this coast, we are not able to shed further light on this. Underwater photographs of Kyphosus species from South Australia and Victoria supplied by Rudie Kuiter and obtained from web searches were all identified as K. sydneyanus . No significant meristic or morphometric sexual dimorphism was apparent in K. gladius , as is consistent with other species of Kyphosus ( Sakai & Nakabo 1995; 2004; 2006).

Figures

FIGURE 1. Capture locations of Kyphosus gladius sp. nov. (open circles), K. sydneyanus (red stars), K. bigibbus (yellow squares) and K. cornelii (blue triangles). One symbol may represent more than one record.

FIGURE 2. Holotype of K. gladius sp. nov., WAM P. 33456 - 001, 439 mm SL, drawing by SWK.

FIGURE 3. Photo of holotype, paratypes of K. gladius sp. nov. and non-type of K. sydneyanus from Western Australia: A) Kyphosus gladius sp. nov., holotype, WAM P. 33456 - 001, 439 mm SL, B) K. gladius sp. nov., paratype, photo of preserved specimen, WAM P. 30668 - 001, 286 mm SL, C) photo of freshly caught non-type K. sydneyanus, WAM P. 33456 - 002, 193 mm SL (top) and paratype K. gladius sp. nov., WAM P. 33456 - 002, 211 mm SL (bottom), collected at Canal Rocks, south off Perth (33 ° 40 ' S, 114 ° 59 ' E) on 30 May 2010.

FIGURE 4. Underwater photographs of Kyphosus spp. at Rottnest Island, Perth, Western Australia in July 2011: A) Kyphosus gladius sp. nov. (circle) and K. sydneyanus (square), specimens not collected, B) K. sydneyanus (square) among school of Kyphosus gladius sp. nov. (circles), specimens not collected. Photos by KDC.

FIGURE 5. Relationships between Australian Indo-Pacific species of Kyphosus: A) Bayesian analysis of mtDNA cyt b, control region, partial 12 S, and tRNA-regions (tRNA-Thr, tRNA-Pro and tRNA-Phe), B) Bayesian analysis of nDNA RAG 1, RAG 2 and Tmo- 4 C 4. Bayesian posterior probabilities are given as percentages next to branches, all branches have a support of 100 % unless otherwise specified. Numbers above branches indicate Bayesian posterior probabilities.

FIGURE 7. Minimum spanning network showing the molecular difference in partial cyt b mtDNA in K. gladius sp. nov., K. sydneyanus and K. bigibbus. Length of branches reflects the number of substitutions between haplotypes. Size of circles reflects number of individuals with identical haplotype. Black dots represents hypothetical unsampled haplotypes.