Bomolochus bramus, Ho, Ju-Shey & Lin, Ching-Long, 2009

Ho, Ju-Shey & Lin, Ching-Long, 2009, Bomolochus bramus n. sp. (Copepoda, Poecilostomatoida, Bomolochidae) from the pomfrets (Bramidae) off Taiwan, with a list of nominal species and key to valid species of Bomolochus von Nordmann, 1832, Zootaxa 2092, pp. 47-57 : 48-54

publication ID	https://doi.org/ 10.5281/zenodo.187513
DOI	https://doi.org/10.5281/zenodo.6213330
persistent identifier	https://treatment.plazi.org/id/9A71E010-1F63-2A09-FF14-FB029A8E32C2
treatment provided by	Plazi
scientific name	Bomolochus bramus
status	sp. nov.

Treatment

Bomolochus bramus n. sp.

( Figs 1–2 View FIGURE 1 View FIGURE 2 )

Material examined. Three ovigerous Ƥ on gills of Pacific pomfret, Brama japonica Hilgendorf : 2 Ƥ on 2 (out of 10) host fish landed at Tai-Dong Fishing Port in Tai-Dong County on 3 October, 2007 and 1 Ƥ on 1 (out of 13) host fish landed at the same port on 20 December, 2007; and 1 ovigerous Ƥ on 1 (out of 5) brilliant pomfret, Eumegistus illustris Jordan & Jordan, landed at the same port on 6 November, 2008. Holotype ( USNM 1120935) and intact paratype ( USNM 1120936) deposited in the National Museum of Natural History, Smithsonian Institution, Washington, DC; 2 dissected Ƥ in the collection of the second author.

Female. Body ( Fig. 1 View FIGURE 1 A) 2.33 (2.12–2.54) mm long, excluding setae on caudal rami. Cephalothorax wider than long, 0.66 (0.64–0.68) × 1.09 (1.04–1.16) mm, with broadly rounded rostrum protruding between bases of antennule and distinct central sclerite extending posteriorly from base of rostrum ( Fig. 1 View FIGURE 1 A). First pediger completely fused to cephalosome; other pedigers on prosome distinctly separated from each other and becoming narrower posteriorly. Urosome distinctly shorter than prosome, measuring 0.82 (0.78–0.84) mm long, about ½ of body length. Genital double-somite distinctly wider than long, 0.23 (0.20–0.26) × 0.33 (0.32–0.36) mm. Abdomen 3-segmented ( Fig. 1 View FIGURE 1 C); all somites distinctly wider than long; first two somites with wide band of spinules running across posterior margin of ventral surface; anal somite with 2 patches of spinules on ventral surface.

Caudal ramus ( Fig. 1 View FIGURE 1 C) longer than wide, 112 (105–120) × 59 (57–65) µm, with patch of spinules on ventral surface and usual 2 long and 4 short setae. Egg sac ( Fig. 1 View FIGURE 1 A) large, longer than body (2.64 mm long), containing multiseriate eggs.

Rostral area ( Fig. 1 View FIGURE 1 D) with T-shaped sclerite armed with pair of small, sharply pointed tines. Antennule ( Fig. 1 View FIGURE 1 E) 5-segmented, with indistinctly separated 2nd and 3rd segments. Basal part (expressed segments 1–2) fringed with 14 robust, pilose setae and 1 recurved hook (modified 4th element), in addition to 7 naked, slender setae on dorsal side and 6 small, plumose setae on ventral side. Armature formula of cylindrical distal part: 4, 2 + 1 aesthetasc, and 7 + 1 aesthetasc. Antenna ( Fig. 1 View FIGURE 1 F) 3-segmented; proximal segment largest, carrying long, plumose outer seta at tip; middle segment smallest, bearing short, naked medial seta; terminal segment carrying rows of fine denticles on ventral surface and protruded distally into large, blunt, cylindrical process with ventral denticles; also armed distally with 4 unequal, curved, long claws, 4 naked setae, and 1 pectinate process. Labrum ( Fig. 1 View FIGURE 1 G) with 2 large patches of spinules on ventral surface and rows of long setules along posterolateral margin. Mandible ( Fig. 1 View FIGURE 1 H) tipped with 2 unequal blades serrated along posterior margin. Paragnath ( Fig. 1 View FIGURE 1 I) an oblong lobe armed with patch of setules on bulbous base. Maxillule ( Fig. 1 View FIGURE 1 J) with 1 small, naked, 1 large, plumose, and 2 large, pilose setae. Maxilla ( Fig. 1 View FIGURE 1 K) 2-segmented; proximal segment large, armed with small, subterminal seta on medial margin; distal segment small, armed with 1 tiny, naked seta and 2 large, spinulose, pointed elements. Maxilliped ( Fig. 1 View FIGURE 1 L) 3-segmented; proximal segment with subterminal seta on medial margin; middle segment with lateral conical projection and 1 robust, pilose and 1 slender, plumose setae on medial margin; terminal segment a sigmoid claw bearing auxiliary hook and large, basal pilose seta.

Armature on rami of legs 1–4 as follows (Roman numerals indicate spines and Arabic numerals represent setae):

Outer margin of coxa and first two endopodal segments of leg 1 ( Fig. 2 View FIGURE 2 A) ornamented with row of long setules; anterior surface of basis with horizontal rows of small, scale-like sculptures above central platelet; intercoxal plate bearing curved row of sculptures; distal margin of first two endopodal segments with spinules. Outer surface of coxa of leg 2 ( Fig. 2 View FIGURE 2 B) with rows of long spinules; proximal exopodal segment with rows of long setules in addition to large patch of spinules; same area on other two exopodal segments with spinules only. Exopodal segments on legs 3 ( Fig. 2 View FIGURE 2 C) and 4 ( Fig. 2 View FIGURE 2 D) with patch of spinules only. Terminal segment of leg 4 endopod ornamented with long setules along outer margin and long spinules along distal margin.

Leg 5 ( Fig. 2 View FIGURE 2 E) 2-segmented; proximal segment short, armed with outer plumose seta and cluster of setules on outer distal corner; distal segment about 2 times as long as wide, carrying 1 long and 3 short pinnate, setiform elements and fringed with 3 large patches of long spinules along both margins and on anterior surface close to tip. Leg 6 ( Fig. 1 View FIGURE 1 B) represented by 3 long, pinnate setae on protuberance located in pit for attachment of egg sac on genital double-somite.

Male. Unknown.

Etymology. The specific name is derived from the family name of the host.

Remarks. This is the first report of a bomolochid copepod from pomfret fishes ( Bramidae ). Bomolochus bramus n. sp. is not a common parasite. In our past five years of sampling, 28 Pacific pomfrets ( Brama japonica ) and 16 brilliant pomfrets ( Eumegistus illustris ) were examined on ten occasions, but only four parasites were found on three occasions from four hosts.

Currently, three species of Bomolochus are known from the fishes of Taiwan. They are: B. megaceros Heller, 1865 ; B. minus Lin & Ho, 2005 ; and B. selaroides Pillai, 1965 (see Lin & Ho 2005). The new species TABLE 1. List of nominal species of Bomolochus von Nordmann, 1832 and their present allocation. (a indicates the species was placed originally in Parabomolochus Vervoort, 1962 , which was synonymized subsequently with Bomolochus by Vervoort (1969). b indicates the species was placed originally in Artacolax Wilson, 1908 , which was synonymized subsequently with Bomolochus by Vervoort (1962)).

can be distinguished from B. megaceros and B. selaroides in the possession of a short spine (about as long as its neighboring outer pilose setae) on the proximal segment of the antennule. It is also easily distinguished from B. minus in the lack of scale-like sculptures on the exopodal segments of legs 2–4.

So far as we are aware, eight species of Bomolochus are known from the fishes of the Indo-West Pacific. In addition to the above mentioned three species, there are B. bellones Burmeister, 1853 , B. decapteri Yamaguti, 1936 , B. multiceros Pillai & Natarajan, 1977 , B. myctophi Avdeev, 1993 , and B. sinensis ( Cressey, 1970) (see Avdeev 1993; Lin & Ho 2005). The new species is unlike these five species in having large patches of spinules on the ventral side of the anal somite and caudal rami in combination with an armature of II, I, 5 on the distal exopodal segment of leg 4 and a short terminal segment on the endopod of leg 4 (with length/width ratio of 1.55) furnished with long setules along the outer margin and spinules along the terminal edge.

In comparison with its congeners occurring outside the Indo-West Pacific, the new species seems to be closest to B. nitidus Wilson, 1911 in its general appearance, the size of the caudal ramus, structure of the terminal endopodal segment of leg 4, and the structure and ornamentation of leg 5. However, the new species can be distinguished from B. nitidus by having an armature formula of II, I, 5 on the terminal exopodal segment of legs 3 and 4, the outer surface of the exopod of legs 2–4 densely covered with spinules, and an inner plumose seta on the first two endopodal segments of leg 4.