Syst Parasitol (2007) 67:19–24 DOI 10.1007/s11230-006-9062-6 ORIGINAL PAPER Lamproglena hepseti n. sp. (Copepoda: Lernaeidae), a gill parasite of the African pike Hepsetus odoe (Bloch) from the Okavango River and Delta, Botswana Liesl L van As Æ Jo G van As Received: 21 November 2005 / Accepted: 24 March 2006 / Published online: 7 December 2006 Ó Springer Science+Business Media B.V. 2006 Abstract During surveys of the biodiversity of fish parasites in the Okavango River and Delta, Botswana, specimens of Lamproglena von Nordmann, 1832 were found associated with the African pike Hepsetus odoe (Bloch). This Lamproglena species distinctly differs from all known species based on morphological features, in particular the cephalothorax and the maxilliped; it is described as L. hepseti n. sp. and is specific to its host, the African pike. Introduction Copepod fish parasites of the genus Lamproglena von Nordmann, 1832 have previously been recorded from the African, Palaearctic and Oriental regions. All species of the genus except one are gill parasites of freshwater fishes. The single record of Lamproglena lichiae von Nordmann, 1832 from a marine fish was regarded as suspect and rejected by Fryer (1968). Piasecki (1993), however, came to the conclusion that L. L van As (&) Æ J. G van As Department of Zoology & Entomology, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa e-mail: vanasll.sci@mail.uovs.ac.za L. lichiae is a valid species after the examination of the original type-material, but its status as a marine fish parasite remains uncertain. To date, 14 species have been found in Africa, with only three recorded from the Zambezi River system and further south, i.e. Lamproglena hemprechii von Nordmann, 1832 from a single specimen of the tiger fish Hydrocynus vittatus (Castelnau) in Lake Kariba (Douëllou & Erlwanger, 1994), L. hoi Dippenaar, Luus-Powell & Roux, 2001 from two species of Barbus Cuvier & Cloquet in Mpumalanga Province, South Africa (Dippenaar, Luus-Powell, & Roux, 2001) and L. clariae Fryer, 1956 from catfish hosts in the Vaal River Barrage, Gauteng Province, South Africa (Tsotetsim, Avenant-Oldewage, & Mashego, 2004). During parasitological surveys carried out in the Okavango River and Delta, Botswana, between 1998 and 2005, numerous specimens of a Lamproglena species were collected from more than 50 specimens of the African pike Hepsetus odoe (Bloch). This parasite has distinct features setting it apart from all the known members of Lamproglena and is described below as a new species. Materials and methods Fishes were collected at different localities in the Okavango River and Delta using gill-nets as well 123 20 as rod and line and kept in aerated aquariums until examination in the field laboratory. Fishes collected were identified using Skelton (2001). The fish were anaesthetised and killed with an overdose of MS222, after which the gills were removed and examined using a Nikon SMZ 800 dissecting microscope for the presence of Lamproglena specimens and other ectoparasites. Copepods were removed and fixed in 70% ethanol. In the laboratory in Bloemfontein some specimens were transferred to lactic acid into which a small amount of lignin pink was dissolved; these were then drawn with the aid of a microscope drawing tube. Other specimens were prepared for scanning electron microscopy using standard techniques for parasitic crustaceans and examined under a JEOL WINSEM JSM 6400 at 5 kV. The description is based on measurements of 30 females examined by light and scanning electron microscopy. Measurements are given in millimetres as the arithmetic mean followed by the range in parentheses. Body measurements of the Lamproglena species collected from Hepsetus odoe in different localities are summarised in Table 1. Species names of fishes in some of the earlier works, i.e. Hydrocynus dentex (Hasselquist) and Alestes nurse (Rüppel) have changed. Names used in this paper are from Fish Base www.fishbase.org (version 11.05). Subclass Copepoda Milne Edwards, 1840 Order Cyclopoida Burmeister, 1834 Family Lernaeidae Cobbold, 1879 Genus Lamproglena von Nordmann, 1832 Lamproglena hepseti n. sp. Type-host: African pike Hepsetus odoe (Bloch) (Hepsetidae). Type-locality: Okavango River at Shakawe (S18°26¢05¢¢, E21°54¢23¢¢), upper Panhandle. Other localities: Okavango River & Delta at Nxamaseri (S18°37¢35¢¢, E22°06¢24¢¢) middle Panhandle; Seronga (S18°49¢49¢¢, E22°24¢23¢¢) lower part of Panhandle; Duba (S18°58¢21¢¢, E22°34¢ 28¢¢) northern part of Delta; Boro River (S19°33¢54¢¢, E23°12¢16¢¢) southern part of Delta. Site of infection: Gill-filaments. 123 Syst Parasitol (2007) 67:19–24 Type-material: Holotype: female 2000/08/07–1 1 (NMBP 297), in the collection of the National Museum, Bloemfontein, South Africa; paratypes: 10 females 2000/08/19–4 (NMBP 298) in the same collection; paratypes: 5 females 1998/6/21–16 (BMNH 2005.2649-2653) in the collection of the Natural History Museum, London. Other material: 50 females 1999/6/27–1/, 1999/7/2– 3, 2000/7/27–3, 2000/8/14–4, in the collection of the Aquatic Parasitology Research Group, Department of Zoology & Entomology, University of the Free State. Etymology: Named after the fish host, Hepsetus odoe, which is endemic to Africa. Description of adult female (Figs. 1, 2; Table 1) Body elongate (Fig. 1A–C), length 3.9 (3–4.6), divided into 3 regions, i.e. cephalothorax, thorax and abdomen; segmentation distinct. Cephalothorax broad, width 0.4 (0.2–0.5), comprising 14.6% of total body length; dorsal surface almost flat; lateral margins of cephalothorax extended ventrally on either side into large thumb-like protrusion with broad base (Figs. 1A, 2A, B, D). Thorax consists of pedigerous somites: somite 2 width 0.4 (0.3–0.5); somite 3 width 0.5 (0.4–0.6) and somite 4 width 0.6 (0.4– 0.7), increasing in diameter posteriorly (Figs. 1B, C, 2A). Genital somite width 0.4 (0.2–0.45), separated from body by deep constriction (Fig. 1B, C). Orifices of oviducts situated dorsolaterally (Fig. 1A, B); egg string uniseriate, extending sometimes to twice length of abdomen, containing up to 55 (mean 38) eggs per string. Eggs mature in oviduct, visible through body wall of third and fourth pedigerous somites. Abdomen 3-segmented, length 1.9 (1.3–2.3), width 0.3 (0.15–0.4), tapering posteriorly, comprising 48.2% of total body length (Fig. 1A,C). Caudal rami (Fig. 1G) conical, fused with abdomen, tapers to sharp point, directed slightly inward, adorned laterally with 2–4 minute sharply pointed setae. Antennule (Figs. 1D, 2B, C) uniramous, 4-segmented; basal segment broad; consecutive segments progressively smaller; ventral margin with row of 16 setae of varying sizes; distal segment terminates in 4 setae. Antennae (Figs. 1D, 2B, C) Syst Parasitol (2007) 67:19–24 A 21 C B D E F I H J K G L Fig. 1 Microscope projection drawings of Lamproglena hepseti n. sp., female. A. Lateral view; B. Dorsal view; C. Ventral view; D. Antennule and antennae; E. Oral region and maxillae; F. Maxilliped; G. Furcal rami; H. Leg 1; I. Leg 2; J. Leg 3; K. Leg 4; L. Leg 5. Scale-bars: A-C, 1 mm; D-F, 50 lm; G,J, 100 lm; H,L, 5 lm; I,K, 10 lm uniramous, 4-segmented; basal segment unadorned; third segment with 2 distinct scabrous areas, without setae; second segment with 3 ventral setae; distal segment with single ventral seta, terminating in 4 setae. Oral region surrounded by broad, horseshoe-shaped, sucker-like labrum, 123 22 Fig. 2 Scanning electron micrographs of Lamproglena hepseti n. sp., female. A. Lateral view of cephalothorax and thorax; B. Ventral view of cephalothorax and first thoracic legs; C. Antennule and antennae; D. Lateral view 123 Syst Parasitol (2007) 67:19–24 of cephalothorax with thumb-like extension; E. Spermatophore and leg 5 (arrowed); F. Maxilliped. Scale-bars: A, B, D–F, 100 lm; C, 10 lm Syst Parasitol (2007) 67:19–24 23 Males not known, but in some specimens paired spermatophores observed (Fig. 2E). forming anterior margin of oral region (Figs. 1E, 2B). Mandibles and maxillules not observed. Maxillae large (Figs. 1E, 2B), 2-segmented, hookshaped, taper from broad base to sharp claw; tips of claws positioned in centre of oral opening. Maxilliped large (Figs. 1F, 2B), 2-segmented; base broad, tapers towards second segment; second segment directed inward, terminates in 2 pairs of claws, each with 1 large and 1 small claw (Fig. 2F). Thoracic legs 1 to 4 similar (Fig. 1H–L), biramous; sympod projects from body surface; exopod slightly larger than endopod, both 2-segmented; exopod terminates in 2 setae; endopod terminates in 1 seta. Exopod of all legs with single seta at base of outer protopod. Leg 5 (Figs. 1L, 2E) a minute process, with 3 terminal setae. Colour of live specimens off-white, with dark red colour of ingested blood clearly visible throughout digestive system. In gravid females, pedigerous somites 3 and 4 appear dark due to developing embryos. Discussion Lamproglena hepseti n. sp. can be distinguished from all other species of the genus based on its general morphology and on differences in the cephalothorax and maxilliped. This is the only species so far recorded with a huge, ventrally extended posterio-lateral part of the cephalothorax. This structure serves as a holdfast for attachment on the gill filament of the host (Fig. 2D). Another distinct feature of L. hepseti is the maxilliped which terminates in four claws (Fig. 2F). The maxilliped of most Lamproglena species, including L. hemprechii, L. hoi, and L. clariae, previously recorded from southern Africa, bears three hook-like terminal spines or claws. In L. elongata Capart, 1956 the maxilliped Table 1 Body measurements (in mm), prevalence and intensity of Lamproglena hepseti n. sp. females collected from Hepsetus odoe at localities in the Okavango River and Delta, Botswana Shakawe (n = 30) Minimum Maximum Mean Standard deviation Nxamaseri (n = 12) Minimum Maximum Mean Standard deviation Seronga (n = 7) Minimum Maximum Mean Duba (n = 12) Minimum Maximum Mean Standard deviation Boro (n = 12) Minimum Maximum Mean Standard deviation TL CtL CtL % TL CtW ThL S2 S3 S4 GsW AW AL AL% TL 3 4.6 3.9 0.49 0.4 0.8 0.6 0.10 10.81 17.50 14.6 1.65 0.2 0.5 0.4 0.09 1.1 1.8 1.4 0.18 0.3 0.5 0.4 0.09 0.06 0.6 0.5 0.12 0.4 0.7 0.6 0.10 0.2 0.45 0.4 0.06 0.15 0.4 0.3 0.05 1.3 2.3 1.9 0.28 41.94 54.05 48.2 2.98 3.8 4.9 4.5 0.31 0.4 0.7 0.5 0.09 9.09 14.29 11.9 1.45 0.4 0.6 0.4 0.06 1.4 1.8 1.5 0.13 0.4 0.5 0.5 0.05 0.5 0.7 0.6 0.07 0.6 0.8 0.7 0.07 0.4 0.45 0.4 0.02 0.25 0.35 0.3 0.03 1.6 2.2 2.0 0.16 40.82 46.67 44.4 1.72 4 4.6 4.3 0.5 0.6 0.5 11.11 13.95 12.2 0.4 0.4 0.4 1.6 1.8 1.7 0.4 0.5 0.4 0.5 0.6 0.5 0.55 0.7 0.6 0.3 0.4 0.4 0.3 0.3 0.3 1.9 2.3 2.1 45.24 51.11 49.0 4 5 4.6 0.27 0.6 0.7 0.6 0.05 12.77 15.00 13.7 0.73 0.4 0.5 0.4 0.03 1.5 1.9 1.7 0.12 0.5 0.6 0.5 0.04 0.55 0.7 0.6 0.06 0.5 0.8 0.7 0.10 0.4 0.5 0.4 0.04 0.2 0.35 0.3 0.03 1.9 2.4 2.2 0.14 47.5 51.11 48.5 1.29 3.8 4.7 4.3 0.25 0.5 0.6 0.6 0.04 12.20 15.00 13.7 0.79 0.4 0.4 0.4 0.00 1.5 1.8 1.6 0.11 0.4 0.55 0.5 0.06 0.5 0.65 0.6 0.05 0.6 0.8 0.7 0.06 0.3 0.5 0.4 0.06 0.2 0.3 0.3 0.03 1.8 2.3 2.1 0.16 45 51.11 48.1 1.56 Total number of fishes examined, 125; total number of fishes infested, 53; prevalence, 42.4%; intensity, 1–1 3. Abbreviations: AL % TL, abdomen length as % of total length; AL, abdomen length; AW, abdomen width; CtL % TL, cephalothorax length as % of total length; CtL, cephalothorax length; CtW, cephalothorax width; GsW, genital segment width; n, number of specimens measured; S2, S3, S4, thorax segments 2, 3 and 4; ThL, thorax length; TL, total length 123 24 terminates in five spines and in L. cornuta Fryer, 1965 a single spine (Fryer, 1968). During eight years of fish parasite surveys in the Okavango River and Delta, we examined specimens of all of the 72 species of fish occurring in the Botswana part of the Okavango River system. In addition to L. hepseti n. sp. on Hepsetus odoe, two other species of Lamproglena were collected occurring throughout the Panhandle and Delta, i.e. L. monodi Capart, 1944 associated with a variety of cichlid species and L. clariae associated with the sharptooth catfish Clarias gariepinus (Burchell) and the blunt-tooth catfish C. ngamensis Castelnau (unpublished data of the Aquatic Parasitology Research Group). This is the first record of a Lamproglena species from the African pike, which is endemic to the African continent and is the sole representative of the Family Hepsetidae. It was found throughout the Okavango River System, at habitats in the Panhandle in the vicinity of Shakawe, Nxmaseri and Seronga, as well as in the Delta proper, i.e. Duba Lagoon and Boro River (Table 1). Of the total 125 African pikes examined, the prevalence of infestation was 42.4%. The L. hepseti populations from the different localities showed very little difference in body measurements. Lamproglena species have previously been recorded from other members of characin fishes, i.e. L. hemprichii on Hydrocynus forskahlii (Cuvier) from Egypt (Piasecki, 1993; von Nordmann, 1832), on H. vittatus from Lake Bangweule (Fryer, 1959), on H. brevis (Günther) from Niger (Dollfus, 1960; Fryer, 1964), on Brycinus nurse (Rüppel) from the Galma River in Nigeria (Shotter, 1977) and again on H. vittatus from Lake Kariba (Douëllou & Erlwanger, 1994). Fryer (1968) observed that members of Lamproglena show a high degree of host-specificity, being mostly confined to members of a single fish family. Our findings confirm Fryer’s observation, as in our extensive surveys of fishes for ectoparasites in the Okavango River and Delta, 123 Syst Parasitol (2007) 67:19–24 L. hepseti was never found on any other host except the African pike. 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