Friday, June 14, 2013

[Ichthyology • 2013] Two new species of Snappers (Lutjanidae: Lutjanus) from the Indo-West Pacific ; Lutjanus indicus from Indian Ocean & L. papuensis from western Pacific

Two new species of snappers, genus Lutjanus, are described from Indo-West Pacific seas. Lutjanus indicus is described from 20 specimens, 54.7–226 mm SL, from western Thailand, India, Sri Lanka, and Bahrain. It has also been photographed at Oman and the Andaman Islands (tissue sample also taken). It has invariably been confused with its sibling species, L. russellii, from the western Pacific. Comparison of the mitochondrial cytochrome c oxidase subunit 1 (CO1) genetic marker utilised in DNA barcoding produced a genetic divergence of about 4.1 % between L. indicus and its closest congener, L. russellii. In addition, significant colour differences are useful for separating the two species, specifically a series of seven narrow yellow-to-brown stripes on the side, obliquely rising (except lower two) dorsally and posteriorly, which are present on both juveniles and adults of L. indicus. Lutjanus papuensis is described from four specimens, 173–259 mm SL, collected at Cenderawasih Bay, West Papua and purchased from fish markets at Bali and western Java, Indonesia. It has also been observed at Timor Leste, northern Papua New Guinea, and the Solomon Islands. It is most closely related to L. bitaeniatus from eastern Indonesia and north-western Australia, but differs notably by its unique colour pattern (bluish to grey on upper side, yellow-orange below lateral line with bright yellow anal and pelvic fins), wider interorbital, deeper body shape, and flatter snout-forehead profile. Its status was also confirmed by genetic analysis. Comparison of the mitochondrial cytochrome c oxidase subunit 1 (CO1) genetic marker utilised in DNA barcoding produced a genetic divergence of about 2.7 and 3.9 % between L. papuensis and its closest congeners, L. bitaeniatus and L. lemniscatus, respectively.

Key words: snappers, Lutjanus, Lutjanidae, new species, reef fish, taxonomy, DNA barcoding, Indo-Pacific.

Lutjanus indicus, n. sp.

Etymology. The species is named indicus with reference to its Indian Ocean distribution

Distribution and habitat. The new species is known with certainty from the northern continental margin of the Indian Ocean including western Thailand, Myanmar, Andaman Islands, Sri Lanka, India, Gulf of Oman (Randall 1995), and Arabian Gulf. Allen and Talbot (1985) recorded L. russellii from the southern Red Sea, Zanzibar, South Africa, Seychelles, Madagascar, and Mauritius, and we provisionally include these records as L. indicus, but the status of the Red Sea and western Indian Ocean population needs to be reassessed, preferably utilising genetic analysis.
We observed this species in coral-reef habitat at western Thailand, Myanmar, and the Andaman Islands. It was generally encountered solitary or in small groups in about 5–15 m depth. It is also taken by trawlers in deeper water (to at least 50 m) and regularly appears in fish markets. There is scant information on juvenile habitat, but we suspect it is similar to that of L. russellii young, which consists of brackish mangrove estuaries and lower reaches of freshwater streams.

Lutjanus papuensis, n. sp.

Etymology. The species is named papuensis after the West Papuan location where it was first collected. Also, West Papua (particularly Cenderawasih Bay) appears to be the stronghold of the distribution, judging from its abundance compared to other locations within the known range. The species was also referred to as the Papuan Snapper by Allen and Erdmann (2012).

Distribution and habitat. Allen and Erdmann (2012) reported this species from Indonesia (West Papua Province), Papua New Guinea (Manus Island and Milne Bay Province), and the Solomon Islands (Malaita, Santa Ysabel, and New Georgia). In addition, M. Erdmann observed a single individual at Timor Leste during a 2012 survey. Although two of the paratypes were purchased at fish markets in Bali and western Java, their exact origin is uncertain, given that fishes entering these markets can be caught throughout the Indonesian Archipelago. 
The habitat consists of coastal fringing reefs in about 6–15 m depth. It is generally seen solitarily or in small groups. Cenderawasih Bay in West Papua Province, Indonesia is the only location where we have seen it on a regular basis. Otherwise, it is generally rare. Only six individuals were encountered during a month-long survey by G. Allen at the Solomon Islands in 2004. We have not encountered any juvenile fish or subadults under about 150 mm SL despite considerable searching. It appears likely they are confined to a particular habitat not frequented by divers, perhaps either dense mangroves or deeper reefs (i.e. below 70 m).

Allen, G.R., W.T. White & M.V. Erdmann. 2013. Two new species of snappers (Pisces: Lutjanidae: Lutjanus) from the Indo-West Pacific. Journal of the Ocean Science Foundation.  6: 33-51.