Pennella filosa ( Linnaeus, 1758 )

Hogans, W. E., 2017, Review of Pennella Oken, 1816 (Copepoda: Pennellidae) with a description of Pennella benzi sp. nov., a parasite of Escolar, Lepidocybium flavobrunneum (Pisces) in the northwest Atlantic Ocean, Zootaxa 4244 (1), pp. 1-38 : 18

Pennella filosa ( Linnaeus, 1758)

( Figs. 2 , 10 )

Synonyms. Pennella biloba Kirtisinghe, 1932 , P. crassicornis Steeenstrup & Lutken, 1861 , P. germonia Leigh- Sharpe, 1931, P. germonia fagei Poisson & Razet, 1954 , P. histiophori Thomson, 1889 , P. orthogorisci Wright. 1877 , P. pustulosa Baird, 1850 , P. rubra Brian, 1906 , P. tridentate Listowsky, 1893 , P. varians Steenstrup & Lutken, 1861

Type host and locality. Xiphias gladius , Atlantic Ocean.

Morphology. Size: 165–205 mm. Papillae: full or partial coverage, generally spherical, variable in size and shape, not found in organized groups. Holdfasts: two or three, laterals can be short or long; dorsal horn, when present, shorter. First antenna with three segments, second with two segments. Plumes: dendritic, complex branching.

Remarks. A valid species. The most frequently documented species of Pennella , P. filosa is also the most recognized species due to its common occurrence on commercially-important fish hosts. It is a large parasite of low host specificity and variable external morphology ( Kabata 1979: Hogans 1987). Reported from many marine fish, but most frequently on large pelagic scombriform fish (swordfish ( Xiphias ), marlins ( Makaira , Tetrapterus ), sailfish ( Istiophorus ) and tunas ( Thunnus )), also on ocean sunfish ( Mola ), and dolphinfish ( Coryphaena ), Atlantic, Mediterranean and Pacific distribution ( Wilson 1917; Causey 1960; Kabata 1979, Hogans 1987, 1988a; Benz & Hogans 1993 and references therein; Williams & Bunkley-Williams 1996; Hernández-Trujillo et al. 2014). Pennella filosa can be distinguished from the other large Pennella which occurs on some of the same types of hosts, P. instructa , by its slightly larger size, (180 mm for P. filosa ; 140 mm for P. instructa ,) the variable holdfast horn shape and number (often three in P. filosa all directed laterally, two only in P. instructa always directed posteriorly) and the configuration and size of the cephalothoracic papillae (random, unorganized and variable in size in P. filosa ; uniform size and in distinct bands/ groups in P. instructa ).

Figures

FIGURE 2. Anterior (embedded) end of female Pennella filosa from Mola mola, dorsal. Scale bar = 1.0 mm. FIGURE 3. Anterior (embedded) end of female Pennella exocoeti from Cheilopogon melanurus, dorsal. Scale bar = 0.5 mm. FIGURE 4. Anterior (embedded) end of female Pennella balaenoptera from Balaenoptera acutorostrata, ventral. Scale bar = 1.0 mm.

FIGURE 10. Pennella filosa, a. habitus, ventral; b. anterior ends of 3 specimens from Mola mola (USNM 47821, 54120), all dorsal; c. first antenna, dorsal; d. second antenna, dorsal; e. sympods of first swimming legs. (b, e from Hogans 1987). Scale bars: a = 5.0 mm; b = 2.0 mm; c- e = 0.02 mm.