Lestidiops mirabilis (Ege, 1933)

Ho, Hsuan-Ching & Lin, Tzu-Yung, 2023, Adult morphology and redescription of Lestidiops indopacificus (Ege, 1953), with comments on the features of related species (Teleostei, Aulopiformes, Paralepididae), ZooKeys 1160, pp. 109-124 : 109

Lestidiops mirabilis (Ege, 1933)

Fig. 3A

Paralepis mirabilis Ege, 1933: 228 (type locality: Sulawesi Sea, western Pacific, 4°03'N, 123°26'E; holotype lost).

Lestidium mirabile (Ege, 1933): Harry 1953a: 240 (assigned to Lestidium ). Harry 1953b: 197 (record from Hawaii, adults).

Lestidiops mirabilis (Ege, 1933): Rofen 1966: 331, 337 (assigned to Lestidiops ). Post 1972: 142 (list; type lost). Uyeno et al. 1983: 193 (French Guiana and Suriname, adults). Gloerfelt-Tarp and Kailola 1984 (off Java, Indonesia, adult). Nakabo 2000: 368 (Kyushu, Japan, based on larvae). Ho and Huang 2022: 579 (Australia, adult).

Material examined.

Non - types: AMS I. 29537-004 (1, 210), FRV Kapala, 33°46'S, 151°49'E, east of Sydney , New South Wales, Australia, prawn trawl, 424-439 m, depth 16 Dec. 1980 • BSKU 27461 (1, 238), 27°43'N, 126°26'E, Okinawa Trough , 1,100 m depth, 9 Mar. 1978 . NSMT-P 40253 (1, 261), off Suriname, no other data (possibly reported by Uyeno et al. 1983) • SAIAB 82055 (1, 276), 23°57'36"S, 35°51'36"E, off Mozambique, Western Indian Ocean , 814-831 m depth, 13 Oct. 2007 . SAIAB 203473 (1, ca 180), 10°20'02.4"N, 96°24'14.4"E, Myanmar, Andaman Sea , 28 May 2015 .

Other material

(not examined but with reliable identification). BMNH 1984.1.1.50 (1, 145), 8°45'S, 114°17'E, south of Java, Indonesia, eastern Indian Ocean (listed by Gloerfelt-Tarp and Kailola 1984) • USNM 163317 (1, 163), CAS-SU18635 (1, 131.5), ANSP 72175 (1, 170), and POFI 628 (1, 170), all from Hawaii (listed by Harry 1953b; Rofen 1966) .

Diagnosis.

Species of Lestidiops with PVO below dorsal-fin base, anus slightly behind the base; anal-fin rays 28-30; lateral-line scales: PVLL 35-40, PDLL 36-39, PALL 51-56, TLL 63-67+8-22 = 73-85; vertebrae: PHV 36-42, PDV 35-38, PVV 36-39, PAV 50-55, CV 43-45, TV 81-87; total gill rakers 44-61. Adults with body uniformly dark brown to black, densely and evenly covered with melanophores; juveniles pale with broad, dark bands.

Distribution.

According to Ege (1953), circumglobal, including the western Atlantic, Indian, and central Pacific oceans based on larvae and juveniles, but more or less restricted to tropical regions. Adult specimens recorded from Indonesia ( Gloerfelt-Tarp and Kailola 1984), Hawaii ( Harry 1953b), Australia ( Ho and Huang 2022), and Suriname and French Guiana ( Uyeno et al. 1983); newly reported from Okinawa Trough, Myanmar, and Mozambique in present study. Bathymertic range 424-1,100 m for adults.

Remarks.

The information on this species in Tables 1 , 2 combines literature data with measurements and counts from examination of voucher specimens in earlier reports (e.g., Harry 1953b; Ho and Huang 2022) and additional specimens. Although L. mirabilis is a widespread species, adults appear to be rare, with only about 10 specimens known in collections. The specimen from Mozambique has the most lateral-line scales (85, including 63 large + 22 small), whereas others have 73-80 (64-67 + 8-16). The number of large scales is fairly constant among specimens, but because most individuals were collected by bottom trawl and either suffered some degree of skin damage or had their body partly broken, it is possible that small scales at the posterior end of the lateral line are missing in some.

Harry (1953b) counted 11-13 pectoral-fin rays in four adults, whereas 13-14 such fin rays were counted in the present material. The first pectoral-fin element of paralepidids has two rays that are closely attached to each other, as can be seen in stained specimens ( Ho et al. 2019a); Harry (1953b) probably counted them as a single ray, and, if so, his count should have been 12-14 rays.

The number of gill rakers also shows a large variation. The specimen from Suriname has 44 gill rakers in total (12 on the upper limb + 32 on the lower), whereas other individuals have 53-61 gill rakers (10-14 + 39-51). Rofen (1966) noticed that the vertebral counts are different among specimens from the western Atlantic Ocean (81-83) and New Caledonia (86), which he concluded was due to lack of data, not to the existence of different geographic populations. Our only western Atlantic specimen also has 81 vertebrae, whereas three Pacific specimens have 86 or 87 vertebrae. Examination of more specimens may prove that there are consistent differences among populations.

The only specimen reported from New Zealand ( Roberts et al. 2015) shows multiple rows of fine teeth forming tooth plates (in key) and is likely a misidentification of an Arctozenus species.

Figures

Figure 3. Photographs of two Lestidiops from Myanmar A L. extremus (Ege, 1953), SAIAB 203471, ca 157 mm SL, with bars indicating DFO (upper), VFO (lower left), and AFO (lower right) B L. mirabilis (Ege, 1933), SAIAB 203473, ca 180 mm SL, with bars indicating DFO (upper), VFO (lower right), and AFO (lower left) C head of specimen as in B, with arrow pointing to nostrils.