deep blue chromis

description

(Figs. 1 a – 1 c; Table 1; Morphbank 59; DigiMorph 60; GenBank 61; Barcode 62)

Five new species of the damselfish genus Chromis (Perciformes: Labroidei: Pomacentridae) from deep coral reefs in the tropical western Pacific

description

Description. Dorsal rays XIV, 13 (two paratypes with XIV, 12); anal rays II, 13 (II, 12 – 14); all dorsal and anal rays branched, the last to base in some specimens; pectoral rays 19 (one paratype with 18), the upper 2 and lowermost unbranched; pelvic rays I, 5; principal caudal rays 8 + 7 = 15; upper and lower procurrent caudal rays 5, the anterior 3 spiniform, the posterior 2 segmented and unbranched; tubed lateral-line scales 16 | 14 (14 – 16 except for one paratype with 11 | 15); posterior midlateral scales with a pore or deep pit 7 | 6 (5 – 8); scales above dorsal fin to origin of dorsal fin 3.5 (3 – 3.5); scales below lateral line to origin of anal fin 9 (9 – 10); gill rakers 7 + 18 = 25 (6 – 7 + 17 – 18 = 24 – 25), 6 gill rakers on upper limb of gill arch in one paratype, 17 gill rakers on lower limb of gill arch in one paratype); surpaneural (predorsal) bones 3; vertebrae 12 + 13. Body moderately deep, depth 1.73 (1.58 – 1.83) in SL, and compressed, the width 3.23 (2.65 – 3.56) in body depth; head length 3.01 (2.79 – 3.05) in SL; dorsal profile of head with slight convexity anterior to eye, slight concavity dorsal to eye, and slight convexity on nape; snout shorter than orb

Five new species of the damselfish genus Chromis (Perciformes: Labroidei: Pomacentridae) from deep coral reefs in the tropical western Pacific

diagnosis

Diagnosis. Dorsal rays XIV, 12 – 13 (usually 13); anal rays II, 12 – 14 (usually 13); pectoral rays 18 – 19 (usually 19); spiniform caudal rays 3; tubed lateral-line scales 14 – 16; gill rakers 6 – 7 + 17 – 18 (usually 7 + 18; total 24 – 25, usually 25); body depth 1.58 – 1.83 in SL; color when fresh dark gray with a large iridescent dark blue spot at center of each scale; membranes on median fins and pelvic fins opaque charcoal gray, with an iridescent dark blue margin on the spinous portion of the dorsal and anal fins; caudal fin mottled iridescent dark blue and black; pectoral fins with a black ovoid spot covering the basal portion and pectoral-fin axil.

Five new species of the damselfish genus Chromis (Perciformes: Labroidei: Pomacentridae) from deep coral reefs in the tropical western Pacific

discussion

Remarks. This species was first observed by the senior author on May 10, 1997, during a mixed-gas rebreather dive to 120 m on the east side of Augulpelu Reef; Palau (07 º 16.41 ' N, 134 º 31.44 ' E). It was later observed at the same reef at depths of 117 – 139 m from a submersible by Patrick L. Colin and Lori J. Bell in February – March, 2001. In April 2005, Mr. Forrest Young and colleagues observed several individuals of this (or a very similar) species during mixed-gas rebreather dives at depths of 120 – 150 m at Manado, Sulawesi, Indonesia. The type specimens included herein are the first of this species to be collected. From these observations, C. abyssus appears to prefer depths in excess of 115 m, staying close to the substratum among boulders and rock outcroppings, where it takes refuge in small caves and holes. Juveniles and some subadults were also observed around limestone talus. Adults were usually observed singly or in pairs, while subadults and juveniles were seen in small groups. All type specimens were collected in the same general area, where the species is not uncommon. Other Chromis observed in the vicinity include three of the new species described herein (C. br

Five new species of the damselfish genus Chromis (Perciformes: Labroidei: Pomacentridae) from deep coral reefs in the tropical western Pacific