Chimaera phantasma Jordan et Snyder, 1900

Chimaera phantasma Jordan et Snyder, 1900 View in CoL

IUCN standard name :: Silver Chimaera Fig. 2 View Figure 2 , Table 1 View Table 1

Material examined.

UPVMI 3118, 889 mm TL (tail broken), female, fish market, Culasi, Antique Province, Philippines, 27 July 2020, coll. E. A. Obar.

Morphological description.

Body large, compressed, elongated, and tapering towards tail; lateral-line canals prominent and wavy. Head large; lateral-line canals straight rather than wavy. Eyes large, horizontally circular; spiracles absent. Snout short, rounded and very soft; tips gelatinous. Mouth small, connected to nostrils. Nostrils large and rounded. Tooth plates on upper jaw two (obviously separated), broad; tooth plate on lower jaw single, pointed, and curved. First dorsal fin tall with a single, erectile spine; first dorsal spine slender, smooth in front, sharply serrated behind; second dorsal fin short and spineless; dorsal-fin base long, extended to tail area. Anal fin short, deeply notched; anal-fin base small. Pectoral fin large, leaf-shaped; apex bluntly rounded. Pelvic fin small, broadly ovoid. Caudal fin elongated, tapering, lanceolate with distinct upper and lower lobes. Most of posterior portion of tail cut off, but remaining parts of tail narrow, rounded, with smooth edges, and whip-like.

Color of fresh specimen. Body surface silver, underside white; snout black; fin edges black.

Color of preserved specimen. Body surface and fins brown; underside dusky white to gray; snout surface area darker brown, underside white; dorsal-, anal-, and caudal-fin edges black.

Distribution.

western Pacific. Japan, Philippines, Borneo, and Taiwan ( Last et al. 2010; Ebert et al. 2013).

DNA barcode.

The COI sequence of 650 base pairs (bp) was submitted to GenBank under accession number OR 614464.

Conservation status.

Vulnerable.

Remarks.

Chimaera phantasma can reach a maximum total length of 1 m and typically inhabits depths ranging from 90–540 m ( Compagno 1999). There have been reports of occurrences in Philippine waters, including Batangas, Cebu, Negros Oriental (Dumaguete), Palawan, and Zamboanga Del Norte (Dapitan and Dipolog cities) ( Compagno et al. 2005; Aquino et al. 2023).

The specimen collected in this study was identified as C. phantasma based on its COI data (see Fig. 3 View Figure 3 ) and morphological characteristics, including a silver, tapering body with a blunt, fleshy snout; a wavy lateral line; a long first dorsal spine extending beyond the fin apex; an anal fin separated from the caudal fin by a shallow notch; and grayish to blackish fins. These features match the description of C. phantasma provided by Jordan and Snyder (1900), Last et al. (2008), and Finucci et al. (2018). Molecular data analysis suggests that Chimaera argiloba Last, White et Pogonoski, 2008 , Chimaera ogilbyi Waite, 1898 , and C. phantasma are closely related species ( Finucci et al. 2018). This relationship is also observed in the phylogenetic tree generated in this study (Fig. 3 View Figure 3 ). However, according to Last et al. (2008), C. phantasma can be distinguished from C. argiloba by its uniformly gray to black first dorsal fin (vs. pale gray with a distinct white posterior margin in C. argiloba ), and black pectoral fins (vs. gray to brown). Furthermore, C. phantasma can be easily distinguished from C. ogilbyi by the presence of an anal fin (vs. absent in C. ogilbyi ) ( Finucci et al. 2018).