A new Sillago species (family Sillaginidae) with descriptions of six sillaginids from the northern Arabian Sea

Abstract

This study reviewed the taxonomy of six members of the family Sillaginidae and described a new Sillago species, S. panhwari. The description of the new species was based on 55 specimens sampled from commercial catches and from fishery surveys (24°48’8.31“N, 66°45’28.15″E) on the northern Arabian Sea coast of Pakistan. Taxonomic revisions were based on morphometric, anatomical characteristics, coloration patterns, and meristics of Sillago panhwari sp. nov., S. arabica, S. attenuata, S. indica, S. sihama, Sillaginopodys chondropus, and Sillaginopsis domina. The distinctive characteristics of the new species are (1) X−XII spines in the first dorsal fin; (2) I, 21–22 rays 2nd dorsal fin; (3) 3–4/7-8 gill rakers on 1st gill arch, (4) periorbital length (1.4–2.3), (5) 18.0–23.3 ED/HL, (6) 16.7–21.7 int.OW/HL; (7) 39.5–46.5 snout L/HL, (8) 34.1–38.9 post-OL/HL, (9) swimbladder narrow anterior extensions joined at the origin, diverging to terminate on the both side of the basioccipital above the anditory capsule whereas two posterior extensions penetrating into the caudal region, one usually longer than the other and presence of a duck-like process, (10) the head before the interorbital area is steep and the mouth is contracted relative to the other six species investigated; (11) the upper half of the body is pale brown to dull brown, with a light brown lower half; (12) the presence of a faint mid-lateral streak from the base of the pectoral fin to the base of caudal fin; (13) dusky dorsal fins; (14) a chin covered with adipose tissue; (15) a hyaline to transparent anal fin clear of spots; (16) yellowish posterior head region; and (17) pectoral and pelvic fins yellowish and caudal fin dusky. Sillago panhwari sp. nov. resembled its allopatric congeners in coloration patterns and body structure. This study contributed to the identification of a new species and the description of six sillaginids occurring in the northern Arabian Sea coast of Pakistan.