Copeia 2009, No. 1, 110–116

A New (, ) from the Mpozo River in the Democratic Republic of Congo

Melanie L. J. Stiassny1, Robert C. Schelly1, and Victor Mamonekene2

A new species of Alestes from the Mpozo River in the Bas Congo Province of the Democratic Republic of Congo is described and diagnostic characters for the are presented. Alestes inferus, new species, is differentiated from all other members of the genus by its lower and non-overlapping lateral-line scale count (31–33 versus 36–51) and its reduced and non-overlapping vertebral count (39–40 versus 41–49). Within Alestes, the new species appears to be most closely related to A. macrophthalmus and A. liebrechtsii, based on the shared possession by these three species of a tubular, bony extension enclosing the olfactory nerve on the lateral ethmoid, and bifurcated lateral-line canals terminating in two pores. Alestes liebrechtsii and A. inferus are the only species of the genus known from the lower Congo River.

Une nouvelle espe`ced’Alestes est de´crite de la rivie`re Mpozo dans la Province du Bas-Congo en Re´publique De´mocratique du Congo et les caracte`res de diagnose sont donne´s. Alestes inferus sp.nov. se distingue des autres membres du genre par un nombre re´duit, sans chevauchement, d’e´cailles de la ligne late´rale (31–33 contre 36–51), de meˆme qu’un nombre re´duit, sans chevauchement, de verte`bres (39–40 contre 41–49). Parmi les Alestes, la nouvelle espe`ce semble proche de A. macrophthalmus et de A. liebrechtsii du fait de la pre´sence chez ces trois espe`ces d’une extension osseuse tubulaire entourant le nerf olfactif sur l’ethmoı¨de late´ral et des canaux de la ligne late´rale se terminant par deux pores. Alestes liebrechtsii et A. inferus sont la seule espe`ces du genre connue du cours infe´rieur du Congo.

ECENT collections made in the Mpozo River just measurements follow Paugy et al. (2003), with three upstream of its confluence with the Congo main- exceptions. Vertebral counts include the four modified R stream have revealed the presence of a new species of Weberian centra but exclude the terminal, hypural-bearing Alestes in that Congo River affluent. This brings to two the vertebra. Gill raker counts in Table 1 correspond to the number of Alestes species found in the lower Congo region. number of rakers arrayed along the lower limb of the first Paugy (1986) records the presence of a single specimen of arch and exclude the raker in the angle of the arch. Alestes macrophthalmus from ‘‘Congo a` Brazzaville,’’ and it is Longitudinal and lateral-line scale counts terminate at the possible that A. macrophthalmus occurs in the region of Pool hypural fold and do not include the one or two scales over Malebo. However, as far as can be ascertained, prior to the the base of the caudal fin. Throughout this paper, the present study only a single species of Alestes, A. liebrechtsii, phylogenetic species concept is adopted as a basis for species which is well-represented in our mainstream lower Congo diagnosis, and in the accompanying illustrations an asterisk River collections, has been reliably reported from the lower precedes character numbers discussed in the text. Based on Congo region. The new taxon, which shares the synapo- outgroup comparison undertaken in the present study and morphies of Alestes, is readily differentiated from all known on the phylogenetic analysis of Zanata and Vari (2005), the members of the genus and is described herein. use of superscript 1 indicates the hypothesized derived state Although there currently exists no consensus regarding and superscript 0 the plesiomorphic state for each figured the precise relationships of the genus Alestes within the character. characiform family Alestidae (Brewster, 1986; Murray and Stewart, 2002; Calcagnotto et al., 2005; Zanata and Vari, Alestes inferus, new species 2005), none have disputed that the restricted concept of the Figure 1 genus (in the sense of Brewster, 1986 and Paugy, 1986) represents a monophyletic entity. Most recently, Zanata and Vari (2005) provide a list of seven anatomical features Holotype.—AMNH 242136, male, 85.7 mm SL, Democratic optimized as synapomorphic for Alestes sensu stricto. Three of Republic of Congo, Bas Congo Province, Mpozo River main these characters are confirmed as unique and unreversed channel at bridge near confluence with Congo River even among characiforms broadly, and are employed herein mainstream, 5u50950S, 13u299420E, 15 July 2007. in a phylogenetic diagnosis for Alestes. Paratypes.—AMNH 242137, 90.8–78.1 mm SL (4 alcoholic) same data as holotype, AMNH 242138, 94.3–78.0 mm SL (2 MATERIALS AND METHODS alcoholic, 2 cleared and stained), Democratic Republic of Visualization of canal-bearing scales and teeth was aided by Congo, Bas Congo Province, Mpozo River main channel at directing a fine jet of compressed air onto the structures. In bridge near confluence with Congo River mainstream, order to count vertebrae and fin rays, and to visualize other 5u50950S, 13u299420E, 18 July 2007. skeletal features, all specimens were radiographed and some were cleared and stained following a modified protocol Diagnosis.—Distinguished from all congeners by the posses- based on Taylor and Van Dyke (1985). Counts and sion of fewer pored scales along the lateral line (31–33 versus

1 American Museum of Natural History, Department of Ichthyology, Central Park West at 79th Street, New York, New York 10024; E-mail: (MLJS) [email protected]; and (RCS) [email protected]. 2 Institut de De´veloppement Rural, Universite´ Marien Ngouabi, B.P. 69 Brazzaville, Republic of Congo; E-mail: [email protected]. Submitted: 28 November 2007. Accepted: 3 September 2008. Associate Editor: C. J. Ferraris. F 2009 by the American Society of Ichthyologists and Herpetologists DOI: 10.1643/CI-07-252 Stiassny et al.—New Alestes from Lower Congo 111

Table 1. Morphometric and Meristic Data for Holotype and Eight 36–51) and fewer vertebrae (39–40 versus 41–49). Alestes Paratypes of Alestes inferus, New Species. inferus is further differentiated from A. dentex, A. baremoze, and A. stuhlmanni in the possession of fewer gill rakers along Holotype + Paratypes the lower limb of the first arch (15–17 versus 23–58). Morphometrics holotype min max n mean Description.—A medium-sized species, maximum observed Standard length (mm) 85.7 78.0 94.3 9 84.4 size 94.3 mm SL. Relatively elongate, laterally compressed % head length with greatest body depth at or near dorsal-fin origin (mean Eye diameter 35.4 34.3 38.5 9 37.4 body depth 29.6% SL). See Figure 1 for general appearance Interorbital width 35.9 35.3 38.3 9 36.3 and Table 1 for summary of morphometric and meristic data. Dorsal body profile gently convex to caudal peduncle, % standard length except for a straight portion along dorsal-fin base, ventral Head length 24.7 24.3 25.8 9 25.3 profile more convex than dorsal and smoothly rounded to Body depth 29.3 28.7 30.4 9 29.6 anal-fin insertion. Caudal peduncle longer than deep. Predorsal length 49.0 47.2 51.8 9 48.4 Mouth terminal, gape not reaching beyond vertical through Dorsal-adipose 26.8 24.6 26.9 9 26.1 anterior margin of eye. Lower jaw robust. Lower lip thick, Caudal peduncle length 11.9 10.9 12.8 9 11.9 forming pad of tissue in front of dentary tooth row. Eye Caudal peduncle depth 10.1 9.2 10.1 9 9.7 relatively large, bony orbit diameter 34.3–38.5% HL, covered by well-developed adipose membrane with broad ovoid slit Meristics Holotype Paratypes exposing large pupil (Fig. 2). Total number of vertebrae 40 39(6) 40 (2) Premaxilla with three teeth in outer row, each bearing Dorsal fin rays (branched) 8 8 threeorfourcusps,insmootharc(non-alternating), Anal fin rays (branched) 18 16(1) 17(4) 18(3) positioned over anterior inner row teeth, not interspaced Gill rakers (lower limb) 16 15(1) 16(3) 17(4) between them (Fig. 3A). Four inner row teeth on each Lateral-line scales 31 33 premaxilla, the anterior two teeth with an expansive base Lateral line–dorsal fin scale rows 5.5 5.5(3) 6(5) almost as deep as wide, with paired molariform cusps Lateral line–pelvic fin scale rows 2.5 2.5 distally and seven to eight pointed cusps proximally Circumpeduncular scales 12 11(3) 12(5) (Fig. 3B). Third premaxillary tooth bears a slight postero- medial expansion at its base and closely abuts anterior margin of fourth, narrow-based inner row tooth. Four outer

Fig. 1. Alestes inferus, new species (A) AMNH 242136, preserved holotype, 85.7 mm SL, (B) AMNH 242137, paratype, 86.0 mm SL, immediately post mortem. Scale bar indicates 1 cm. 112 Copeia 2009, No. 1

Fig. 2. Alestes inferus, new species, left lateral schematic of head and superficial cranial anatomy. row teeth on contralateral dentaries, each with large central cusp and two to four minor cusps on either side (Fig. 3C). First three teeth have somewhat expanded bases but lack molariform distal cusps. Fourth tooth is markedly smaller than preceding three. A single pair of large, conically recurved, symphyseal inner row teeth on lower jaw Fig. 3. Alestes inferus, new species AMNH 242138, 81.3 mm SL; (A) invariably present (Fig. 3B). maxilla and premaxilla in right lateral view; (B) mouth open in lingual Dorsal-fin rays ii, 8; anal-fin rays iii, 16–18. Origin of view; (C) lower jaw in right lateral view. dorsal fin at, or slightly in front of, vertical through pelvic- fin origin. Pectoral fins relatively long, reaching to just character 120 of Zanata and Vari, 2005). Central rod of the anterior to insertion of pelvic fins. Anal fin distal margin pelvic girdle not extending anterior to the lamellar plate straight or slightly convex with little sexual dimorphism (Fig. 6C*100; character 140 of Zanata and Vari, 2005). The evident in fin shape. Caudal fin large and deeply forked. last three anal-fin pterygiophores are abruptly decreasing in Body covered with large, regularly imbricate scales. Lateral length relative to the more anterior elements (Fig. 7*110; line complete, first 4–5 scales descend steeply to below character 145 of Zanata and Vari, 2005). midlateral line, remaining scales coincide with horizontal scale row. Thirty-one to 33 canal-bearing scales to point of Coloration.—In alcohol (Fig. 1A) base body coloration hypural flexure, one smaller pored scale on caudal-fin base. yellowish brown dorsally, pale cream ventrally. A darkly Lateral-line scales with bifurcating external canal in region pigmented, deep-lying stripe extends from dorsoposterior proximate to overlap with following scale, each bifurcation margin of opercle to base of caudal peduncle, not extending terminating in a small pore (Fig. 4A*51). Five and a half to over caudal fin. Trace of a band of dark melanophores six transverse scales between lateral line and dorsal-fin present above anal fin. Pectoral and pelvic fins creamy origin, two and a half transverse scale rows between lateral white. Adipose fin dusky gray with a narrow marginal band line and pelvic-fin insertion. Fifteen to 17 (mean 16) of darker pigment. Dorsal fin somewhat dusky proximally elongate gill rakers along lower limb of first arch, one raker with yellow-orange band mid-dorsally, dusky gray proxi- in angle of arch, and 10–11 rakers along upper limb of first mally. Anal fin pale proximally becoming darker along distal arch. Total number of vertebrae 39–40 (mean 39). margin. Caudal fin dusky gray with yellow-orange patch posteriorly on dorsal and ventral lobes, distal margin dark Miscellaneous osteological features.—Well-developed, tubular, gray. In life (Fig. 1B) with blue-green iridescence dorsally bony extensions enclosing olfactory nerves present on the and dorsolaterally, silvery-white laterally and ventrally. No orbital face of each lateral ethmoid (Fig. 5A*61; character 29 trace of midlateral band or of melanophores above anal fin. of Zanata and Vari, 2005). Ventral surface of supraorbital Pectoral and pelvic fins pale yellowish hyaline. Dorsal fin without a well-developed ventral process (Fig. 2*70; charac- hyaline proximally, orange distally. Adipose pale dusky gray ter 3 of Zanata and Vari, 2005). Postorbital process of the with a narrow darker gray distal margin. Anal fin pale dusky sphenotic not completely covered by the fifth and sixth gray. Caudal fin pale dusky gray, orange banding along the infraorbital elements and exposed at the posterior margin of posterodorsal and posteroventral lobes, and with a narrow, orbit (Fig. 2*81; character 16 of Zanata and Vari, 2005). dark gray distal margin. Parapophyses of the fifth and subsequent precaudal verte- brae not anteriorly elongated, and not contacting or Distribution and habitat.—Alestes inferus is currently known overlapping the preceding vertebral centra (Fig. 6A*90; only from the type locality in the main channel Mpozo Stiassny et al.—New Alestes from Lower Congo 113

Fig. 4. Lateral-line scale pore morphology of (A) Alestes inferus, new species AMNH 242138; (B) AMNH 219185.

River downstream of the bridge crossing near its confluence Paugy (1986). It is evident from the original description and with the mainstream Congo River, (5u50950S, 13u299420E; the data presented by Paugy (1986) that this taxon is readily Fig. 8). Specimens were collected with cast nets in shallow distinguished from Alestes inferus. water and in deeper pools alongside emergent grasses at the In a recent analysis of the phylogenetic relationships of riverbank over a substrate dominated by large rocks and rock Alestidae, Zanata and Vari (2005) hypothesized that of the rubble. three species of Alestes included in their study, Alestes macrophthalmus was sister to a clade consisting of A. Generic diagnosis and relationships.—The genus Alestes is baremoze and A. dentex. A similar conclusion had been diagnosed by the following characters. Leading edge of the reached by Murray and Stewart (2002) who grouped A. first anal-fin pterygiophore deeply incised with an anterior stuhlmanni with A. baremoze and A. dentex based on the flange terminating well below the apical tip of the central rod of the element (Fig. 7*11; character 143 of Zanata and Vari, 2005). Posterior anal-fin pterygiophores strongly inclined relative to anterior pterygiophores (Fig. 7*21; character 146 of Zanata and Vari, 2005). Gas bladder with a tubular, unilateral extension penetrating well beyond the regular limits of the abdominal cavity, passing over the left side of the anal-fin pterygiophores and into the caudal peduncle (Fig. 7*31; character 200 of Zanata and Vari, 2005). In addition Alestes are large to medium-sized alestids possessing a well-developed adipose eyelid that envelops most of the eye leaving only a slit in the region of the pupil (Fig. 2*41). Alestes are distinguished from the two other alestid genera with well developed adipose eyelids, Hydro- cynus and , by the presence of robust molar- iform premaxillary inner row teeth (versus a single row of tricuspid and conical teeth in ), and by the absence of a third row of molariform premaxillary teeth (versus presence in Bryconaethiops). Alestes includes the species Alestes dentex, A. baremoze, A. Fig. 5. Left lateral view of anterior region of neurocranium with lateral stuhlmanni, A. macrophthalmus, and A. liebrechtsii. A sixth ethmoid shaded in grays and exposed olfactory nerve in black of (A) species, A. ansorgii, from the Quanza and Lucalla Rivers of Alestes inferus, new species AMNH 242138; (B) Angola was included in synonomy of A. macrophthalmus by AMNH 226562. 114 Copeia 2009, No. 1

(Fig. 4A*51). In both A. baremoze and A. dentex the external canal terminates in a single, ventrally oriented branch and pore (Fig. 4A*50), a condition variously present among other alestid taxa examined. We have been unable to confirm the presence of highly divided external canals with multiple dorsal and ventral branches terminating in numerous pores in A. macrophthalmus as described and illustrated by Zanata and Vari (2005:fig. 31), and, instead, all specimens exam- ined in the course of the present study shared the derived lateral-line canal morphology described here and illustrated in A. inferus (Fig. 4A).

Etymology.—Inferus, from the Latin, meaning below, lower, southern. Named in reference to the occurrence of the species below a series of rapids on the lower Congo River, in a south bank tributary.

DISCUSSION The confluence of the Mpozo River with the lower Congo River is situated just upstream of the town of Matadi, below which the Congo River is navigable to the Atlantic, and just downstream of the Zanza-Lufindi rapids (Fig. 8). The Zanza- Lufindi rapids are the last of a series of large rapids that Fig. 6. Fifth, sixth, and seventh precaudal vertebral centra and extend intermittently upstream for over 30 km before associated structures in left lateral view of (A) Alestes inferus, new reaching the main rapids in the vicinity of Inga. Given the species AMNH 242138, (B) Alestes baremoze AMNH 226562; Pelvic extraordinary hydropower of the lower Congo above the girdle, left hand side in dorsal view of (C) Alestes inferus, new species Mpozo confluence, it seems improbable that A. inferus AMNH 242138, (D) Alestes dentex AMNH 215666. occurs above the Zanza-Lufindi rapids, and these rapids appear to mark a major biogeographic boundary along the shared attribute of an elevated number of gill rakers (.23 lower Congo River. A biogeographic disjunct at Matadi was rakers on the lower limb of the first arch). Our own also noted by Thys van den Audenaerde (1964) for the observations are consistent with those assessments, and in haplochromine cichlids along the lower Congo River. Thys addition we find that Alestes inferus shares two synapomor- van den Audenaerde (1964) observed that the lower Congo phies with Alestes macrophthalmus and A. liebrechtsii. The haplochromines are allopatrically arrayed along the Congo first is the presence of a tubular, bony extension completely River mainstream, and in the region of the present study, enclosing the olfactory nerve developed on the orbital face Haplochromis demeusii occurs upstream of Matadi, while of each lateral ethmoid and the orbitosphenoid (Fig. 5A*61; Haplochromis fasciatus is found at and below Matadi. Our Starks, 1926:167; see also Roberts, 1969:441–442). No own collections confirm this and reveal that this distribu- tubular extension of the lateral ethmoid is present in any tional pattern holds not only for haplochromines, but also of the A. baremoze (Fig. 5A*60) examined in this study, nor for a diverse array of other taxa that we have sampled. In in A. dentex or in any other alestid examined; the attribution addition to Haplochromis fasciatus and the new alestid of such a tube to A. baremoze by Monod (1950:42; no species described herein, other species found only in the catalogue number or locality data provided) seems likely due region of the Congo-Mpozo River confluence and/or to a misidentification. The second is the presence of a between Matadi and Boma include the lower Congo characteristic bifurcation of the external canal of lateral-line endemics Steatocranus mpozoensis and holargyreus, scales, each bifurcation terminating in a small pore as well as the more widespread, coastally distributed Awaous lateristriga and Aplocheilichthys spilauchen.

MATERIAL EXAMINED The following comparative materials were included in this study (values after catalog number indicate number of specimens examined and do not necessarily correspond to the total number of specimens in the lot; CS indicates cleared-and-stained preparation, and SL indicates standard length. The American Museum of Natural History is abbreviated AMNH.

Alestes baremoze. AMNH 226562, 2 CS, Benin, Pendjari River; AMNH 226562, 12, 2 CS, Benin, Pendjari River. Alestes dentex. AMNH 219185, 3, Senegal, Richard Toll, Fouta Fig. 7. Right lateral view of anal fin and associated structures of Alestes Region, market; AMNH 226449, 2 CS, Benin, Niger River inferus, new species. at Tunga Village; AMNH 215666, 2, 1 CS, , White Stiassny et al.—New Alestes from Lower Congo 115

Fig. 8. Satellite image of Matadi and associated rapids, Bas Congo Province. Star indicates type locality of Alestes inferus, new species, with inset photograph of locality in Mpozo River main channel at bridge near confluence with Congo mainstream (5u50950S, 13u299420E).

River (Bahr El Abiad); AMNH 215621, 5, Sudan, macrolepidotus. AMNH 240383, 6, 1 CS, Republic of River (Bahr El Abiad); AMNH 226606, 1, Mali, Bani River. Congo, Odzala National Forest; AMNH 228574, 1 CS, Alestes liebrechtsii. AMNH 6186, 1, Democratic Republic of Central African Republic, Goro River. Congo, Bomakandi River, Rungu; AMNH 240755, 2, Dem- Brycinus poptae. AMNH 240385, 5, 1 CS, Republic of Congo, ocratic Republic of Congo, Luilaka River; AMNH 238314, 12, Odzala National Forest. 2 CS, Democratic Republic of Congo, Bodjia Village; AMNH Bryconaethiops microstoma. AMNH 238290, 2, 2 CS, Republic 238300, 10, 2 CS, Democratic Republic of Congo, Ban- of Congo, 1 km east of Kintele. dundu; AMNH 238269, 2, Republic of Congo, downstream Bryconaethiops yseuxi. AMNH 239455, 10, 2 CS, Republic of of Brazzaville, Mbouno; AMNH 227505, 2, Republic of Congo, below Bela. Congo, Sangha River, Bayonga; AMNH 240393, 1, Republic . AMNH 6181, 1, 2 CS, Democratic of Congo, Likouala aux Herbes, Q’Mokenfu. Republic of Congo, Faradje; AMNH 238297, 1, 1 CS, Alestes macrophthalmus. AMNH 217360, 3, 1 CS, Tanzania, Democratic Republic of Congo, Fimi River. Malagarazi River; AMNH 5806, 1 CS, Democratic Republic of Micralestes acutidens. AMNH 231798, 1 CS, Democratic Congo, Junction of Lualaba River with Congo River, Republic of Congo, junction of Lualaba River with Congo Stanleyville (Kisangani); AMNH 6095, 1, Democratic Repub- River, Stanleyville (Kisangani). lic of Congo, Bomakandi River, Rungu; AMNH 6143, 2, Micralestes humilis. AMNH 240417, 3, 1 CS, Republic of Democratic Republic of Congo, Bomakandi River, Rungu; Congo, Likouala aux Herbes. AMNH 6235, 1, Democratic Republic of Congo, Ituri River, interruptus. AMNH 239467, 8, 2 CS, Repub- Avakubi; AMNH 6395, 1, Democratic Republic of Congo, lic of Congo, Foulakari River. Ituri River, Avakubi; AMNH 227526, 2, 1 CS, Republic of Congo, Sangha River, Manondo Island; AMNH 227525, 1, Republic of Congo, Sangha River, Manondo Island. ACKNOWLEDGMENTS hilgendorfi. AMNH 240421, 3, 1 CS, Republic For assistance with permits and logistical support we are of Congo, Likouala aux Herbes. extremely grateful to all at the WWF-CARPO office in Bryconalestes longipinnis. AMNH 12319, 2, Liberia, Kaleata. Kinshasa, and to the staff and administration of the altus. AMNH 240485, 2 CS, Democratic University of Kinshasa, Democratic Republic of Congo. Republic of Congo, Luilaka River. Thanks to J. Lowenstein for the locality photo in Figure 8. Brycinus bimaculatus. AMNH 240384, 8, 1 CS, Republic of Research and travel support was provided by National Congo, Odzala National Forest. Science Foundation grant number DEB 0542540 and the Brycinus comptus. AMNH 239519, 10, 3 CS, Republic of Axelrod Research Fund of the American Museum of Congo, Baluku. Natural History. 116 Copeia 2009, No. 1

LITERATURE CITED et Flore tropicales 40. IRD, Paris, MNHN, Paris, and MRAC, Tervuren. Brewster, B. 1986. A review of the genus Hydrocynus Cuvier Roberts, T. R. 1969. Osteology and relationships of 1819 (Teleostei: Characiformes). Bulletin of the British characoid , particularly the genera Hepsetus, Salmi- Musuem (Natural History) Zoology 50:163–206. nus, Hoplias, Ctenolucius, and Acestrorhynchus. Proceedings Calcagnotto, D., S. A. Schaefer, and R. DeSalle. 2005. of the California Academy of Sciences 36:391–500. Relationships among characiform fishes inferred from Starks, E. C. 1926. Bones of the ethmoid region of the fish analysis of nuclear and mitochondrial gene sequences. skull. Stanford University Publications, University Series, Molecular Phylogenetics and Evolution 36:135–153. Biological Sciences 4:137–338. Monod, T. 1950. Notes d’ichtyologie ouest-africaine. Bulle- Taylor, W. R., and G. C. Van Dyke. 1985. Revised tin de l’Institut Franc¸ais d’Afrique Noire 12:1–71. procedures for staining and clearing small fishes and Murray, A. M., and K. M. Stewart. 2002. Phylogenetic other vertebrates for bone and cartilage study. Cybium relationships of the African genera Alestes and Brycinus 9:107–109. (Teleostei, Characiformes, Alestidae). Canadian Journal of Thys van den Audenaerde, D. F. E. 1964. Les Haplochromis Zoology 80:1887–1899. du Bas-Congo. Revue de Zoologie et de Botanique Paugy, D. 1986. Re´vision syste´matique des Alestes et Brycinus Africaines 70:154–173. africains (Pisces, ). Collection Etudes et The`ses Zanata, A. M., and R. P. Vari. 2005. The family Alestidae O.R.S.T.O.M., Paris. (Ostariophysi, Characiformes): a phylogenetic analysis of Paugy, D., C. Le´veˆque, and G. G. Teugels. 2003. The fresh a trans-Atlantic clade. Zoological Journal of the Linnean and brackish water fishes of West Africa. Volume 1. Faune Society 145:1–144.