BULLETIN OF MARINE SCIENCE, 26(1): 59-64, 1976 A REVIEW OF THE LOPHIID ANGLER FISH GENUS SLADENIA WITH A DESCRIPTION OF A NEW SPECIES FROM THE CARIBBEAN SEA John H. Caruso and Harvey R. Bullis, Jr. ABSTRACT The little known lophiid genus S/adenia, previously represented by two Indo-Pacific species, each known from a single specimen, is reviewed, and a new species described from the Caribbean Sea. Diagnostic features for the genus and species are discussed, and a key to the species is provided. The distinctive but little known lophiid genus, Sladenia, was described by Regan ( 1908) from a single specimen, which he named S. gardineri, collected at a depth of 900 meters off Solomon Island in the Chagos Archipelago. Four years after Regan's (1908) description, a second species, S. remiger, was described by Smith and Radcliffe (in Radcliffe, 1912) from a single specimen obtained during the Philippine expedition of the ALBATROSS, 1910-1917. These two holotypes remained the sole representatives of the genus Sladenia for nearly 60 years until November 1970 when a large specimen of an undescribed species of Sladenia was collected in the Caribbean Sea off Colombia at 1200 m by the FRV OREGON II. A second specimen of this new form was collected off Venezuela at a depth of 900 m by the same vessel in February 1973. These two specimens are described below and are compared with other members of the genus. METHODS Counts and measurements of specimens and comparisons with other lophiid species were made by the first author as part of a revision of the family Lophiidae (in preparation). The measurements used in the following description are somewhat unconventional, and are based on a system devised by the first author for use in the family revision. Conventional measurements, such as head length, head width, head depth, snout length, and snout width, cannot be used for two reasons: lophiids possess a highly mobile 59 suspensorium which makes head shape highly variable, and they lack a distinct posterior opercular margin, bony orbit, and clear external demarcation of the eye. Using preserved material, dried, and cleared and stained skeletal preparations, and dissected material, measurements were selected that showed little or no variation upon movement of the suspensorium. These measurements were made between the various head spines and were redefined as follows: head length is the distance from the premaxillary symphysis to the posteromedial end of the neurocranium, head width is the distance between the pterotic spines, head depth is the distance between the pterotic and lower quadrate spines, snout length is the distance between the premaxillary symphysis and left posterior frontal spine, and snout width is the distance between the frontal bones just posterior to their junction with the lateral ethmoids. Standard length (SL) was measured in the conventional manner, and all measurements were made with either a dial calipers to the nearest 0.1 mm or a beam compass to the nearest 0.5 mm. Accurate counts were insured by making incisions to reveal the bases of the dorsal spines and dorsal, anal, and pectoral rays. Vertebral counts were determined from radiographs. Terminology used in describing the angling apparatus follows Bradbury (1967). Sladenia Regan, 1908 S/adenia Regan, 1908: 250 (type species Sladenia gardineri Regan, 1908, by monotypy).
60 BULLETIN OF MARINE SCIENCE, VOL. 26, NO. I, ]976 Diagnosis.-A genus of lophiid with rounded rather than depressed head, and compressed rather than depressed tail; nasal sacs not constricted at base; very long pseudobranchia; third dorsal spine absent; humeral, subopercular, quadrate, parietal, and articular spines absent; epiotic and interopercular spines low and rounded; vomerine teeth larger than palatine; iliicial bone and second dorsal spine inserting very close together on iliicial pterygiophore; and smooth ridge on frontal bones anterior to eyes and lateral to illicial pterygiophore. KEY TO THE SPECIES OF SLADENIA la. Post-cephalic portion of spinous dorsal fin consisting of one or two spines contained in a loose fold of skin. Cranial spines pointed. Indo- Pacific. 2 1b. Post-cephalic portion of spinous dorsal fin consisting of one embedded spine not contained in a loose fold of skin. Cranial spines low and rounded. Western Atlantic. S. shaefersi new species (p. 5) 2a. Post-cephalic portion of spinous dorsal fin consisting of two spines contained in a loose fold of skin. All cranial spines low, pointed, and of similar size. S. gardineri Regan, 1908 (p. 4) 2b. Post-cephalic portion of spinous dorsal fin consisting of one spine contained in a loose fold of skin. Sphenotic and frontal spines enlarged, the latter greatly. S. remiger Smith and Radcliffe, in Radcliffe, 1912 (p. 4) Sladenia gardineri Regan, 1908 Sladenia gardineri Regan, 1908: 251, pi. 32 (original description; single specimen, 351 mm SL; Indian Ocean, Chagos Archipelago, Solomon Island, 900 m; holotype, BMNH 1908.3.23.281). Diagnosis.-S. gardineri is distinguished from other members of its genus by having a longer head (41.4% of SL); moderate snout length (46.1 % of head length); spinous portion of the dorsal fin consisting of four spines, two cephalic, two post-cephalic (the latter almost completely contained within a loose fold of skin which connects the two spines to the soft dorsal fin); low, sharply pointed cranial spines; and a color pattern of relatively fine, irregular, pale vermiculations on a darker background. Counts and measurements.-d. IV-9; A. 6; Pl' 18; P 2 I, 5; C. 8 (the outcr two elements unbranched, the others branched). Measurements in percent of SL: head length 41.1; head width 26.4; head depth 33.0; snout length 19.1; snout width 8.8; length of iiiicial bone 31. 5; length of second dorsal spine 10.4. Measurements in percent of head length (HL): head width 63.8; snout length 46.1; snout width 21.3. Sladenia remiger Smith and Radcliffe, in Radcliffe, 1912 Sladenia remiger Smith and Radcliffe, in Radcliffe, 1912: 199-200, pi. 16, fig. 1 (original description; single specimen 92.3 mm SL; Gulf of Tomini, Celebes, ALBATROSSstation 5605, cruise 16, lat. 0021'33"N, long. 121"34'10"E, 1294 m; holotype, USNM 70263). Diagnosis.-S. remiger is distinguished from other members of its genus by having a shorter head (27.6% of SL); longer snout (74.1% of HL); spinous portion of the dorsal fin consisting of three spines, two cephalic, one post-cephalic (the latter almost completely contained within a loose fold of skin which connects it to the soft dorsal); well developed cranial spines, with the frontal and sphenotic spines enlarged, the former greatly; and a uniform pale grey coloration, lacking vermiculations or other contrasting pigment. Counts and measurements.-d. 1II-9; A. 7; PI 19; P 2 I, 5; C. 8 (the two outer elements unbranched, the others branched): vertebrae 19. Measurements in per cent of SL: head length 27.6; head width 26.7; head depth 28.8; snout length 20.5; snout width 7.8; length of illicial bone 28.3. Measurements in per cent of HL: head width 96.4; snout length 74.1; snout width 28.2. Sladenia shaefersi, new species Figures 1 and 2 Material examined.-holotype, USNM 214477, 397 mm SL; FRV OREGON II, cruise 22, station 11242; 10oI0'N, 76 14'W; ca. 32 mi. east of Point Baru, Colombia; 1200 m; 71 ft. semi-balloon trawl;
CARUSO AND BULLIS: REVIEW OF THE ANGLER FISH GENUS SLADEN1A 61 Figure 1. Lateral view of the holotype of S. shaefersi. 4 hour tow; 5 November 1970. PARATYPE, USNM 214478, 146.2 mm SL; FRV OREGON II, cruise 43, station 124 of the Miami Laboratory, BOOO/N, 70 0 40'W to 12 54.5'N, 70 0 26.5'W; ca. 29-43 mi. NW of Aruba Island; 850 m; 40 ft. flat trawl; 6 hour tow; 24-25 February 1973. Diagnosis.-S. shaefersi is distinguished from other members of its genus by having an intermediate head length (32.7 and 34.8% of SL in the holotype and paratype respectively); moderate snout length (57.1 and 47.5% of HL in the holotype and paratype respectively); spinous portion of the dorsal fin consisting of three spines, two cephalic, one post-cephalic (the latter completely embedded in subcutaneous tissue and not contained in a loose fold of skin); low, rounded cranial spines, and a color pattern consisting of relatively coarse, irregular, light vermiculations over a brown background covering the dorsal and lateral surfaces of the head and body, and dorsal, anal, caudal, and pectoral fins. Counts and measurements.-d. 111-8 or 9; A. 6; Pl' 18; P2 I, 5; C. 8 (the two outer elements unbranched, the others branched); vertebrae 19. Measurements in per cent of SL (first figure holotype, second, para type): head length 32.7, 34.8; head width 20.2, 25.0; head depth 31.5, 28.3; snout length 18.7, 16.5; snout width 7.8, 7.2; length of illicial bone 38.4, 13.5; length of second dorsal spine 12.9, 6.9. Measurements in per cent of HL (first figure holotype, second, para type): head width 61.5, 71.7; snout length 57.1, 47.5; snout width 23.8, 20.7. Description.-Head rounded, body compressed, with cranial spines low and rounded except those on frontal and sphenotic bones which are slightly produced; pronounced muscular hump immediately behind head; iilicial bone long (13.5-38.4% of SL) and slender; second dorsal spine slender, approximately half length of illicial bone; dorsal spines III, V, VI absent, IV present as
62 BULLETIN OF MARINE SCIENCE, VOL. 26, NO. I, 1976 I 50mm l Figure 2. Dorsal view of the holotype of S. shaefersi. embedded vestige; skin bearing numerous small, lanceolate cirri arranged in irregular rows and patches on head, lower jaw, and pectoral and caudal fins, but confined generally to region of lateral line on body; color pattern in alcohol consisting of dark brown background pigment with irregular light markings covering dorsal and lateral surfaces of head and body, anterior portion of lower jaw, bases of soft dorsal and caudal fins, and dorsal surface of pectoral fins and pseudobrachia (ventral surface of pectoral fins with these markings less numerous but distinct on paratype, but only vague on holotype); ventral surface of head and body and pelvie fins as background pigment but lighter; dorsal, anal, and caudal fins dark brown; illicium and most cirri darker than body background pigment; inside of mouth dusky; peritoneum black; pectoral fins with all rays unbranched and covered with thiek layer of connective tissue, making the rays visible only distally; tips of pectoral rays unpigmented; teeth typically cardiform but proportionally smaller than those of other lophiids. Etymology.-We take pleasure in naming this species in honor of Edward Shaefers, former chief of the Exploratory Fishing and Gear Research Branch of the former Bureau of Commercial Fisheries, in recognition of his outstanding contributions to manne SCIence. DISCUSSION Since the genus Sladenia is known from only four specimens representing three species, little can be said regarding intraspecific variation. However, it is probably quite extensive in this genus, judging from the high degree of variability found in other lophiid species inhabiting greater depths. Whereas meristic features vary little between the three species, variation in the morphometries is marked. Similar results, however, could be obtained with four specimens representing any three lophiid species that inhabit the archibenthic zone. Since the first author's investigation of morphometric variation is presently incomplete, morphometries have been deemphasized in the present discus-
CARUSO AND BULLIS: REVJEW OF THE ANGLER FISH GENUS SLADENIA 63 sion. Instead, several characters that have been thoroughly investigated and found to be useful in distinguishing other lophiid species are discussed below. The number of dorsal spines is the one primary difference between the three species of Sladenia. All three species have a similar arrangement of the illicium and second dorsal spine, and the third dorsal spine is absent in all. The post-cephalic portion of the spinous dorsal, however, differs in the three species. In S. gardineri there are two postcephalic spines, while in S. remiger and S. shaefersi there is only one. In S. remiger this spine is well developed and contained in a prominent fold of skin that connects the spine to the soft dorsal fin, while in S. shaefersi, the spine is merely an embedded vestige and the fold of skin is absent. Additional specimens would be very helpful in analyzing this character, since this region of the spinous dorsal is highly variable in other deepwater lophiids. This character alone would not provide sufficient grounds for considering S. remiger and S. shaefersi specifically distinct. It is apparent that the lengths of the iliicium and second dorsal spine differ greatly in the two specimens of S. shaefersi. This is attributable to ontogenetic increase in spine length, a phenomenon observable elsewhere among the Lophiidae. The cranial spines of the three species also differ. Those of S. shaefersi are low and rounded and barely discernible through the skin. The spines of S. gardineri are low and somewhat more sharply pointed, while those of S. rel17iger are pronounced, especially the greatly enlarged frontal, and the sphenotic spines. The size, shape, and placement of the cranial spines in other lophiid species appear to be quite constant and subject to little, if any, variation (including ontogenetic); hence, the above differences are considered to be on the order of interspecific variation. Color pattern in preservative is also helpful in distinguishing the species of Sladenia. Both S. gardineri and S. shaefersi have similar patterns of irregular light vermiculations on dark backgrounds, but the markings on S. gardineri are much finer. The holotype of S. remiger lacks vermiculations or other contrasting features of pigmentation, as described by Smith and Radcliffe (in Radcliffe, 1912). Color pattern, when present as spots, bars, reticulations, or vermiculations in other lophiid species, appears to be quite constant, and varies only in intensity which is probably due to the nature of the substrate. Distinctive color patterns among the lophiids, however, are usually found in species inhabiting photic or dysphotic regions. The function of such a distinctive color pattern on a species inhabiting 850 meters or more is unknown. One of the most important diagnostic features for lophiid species inhabiting the archibenthic zone is the morphology of the esca. Unfortunately this character could not be used in the present study since the esca was damaged in all four specimens. In two recent imprecise and unacceptable revisions of the family Lophiidae, Y. Le Danois (1973, 1974) without having seen either holotype (Le Danois, pers. comm.), placed Sladenia remiger into synonomy with S. gardineri. In view of the differences discussed above, we feel it advisable at this point to recognize S. remiger as a distinct species. ACKNOWLEDGMENTS The authors thank R. H. Gibbs (USNM) and A. C. Wheeler (BMNH) for the use of their facilities when examining holotypes, and E. Bertelsen (ZMUC), and especially F. H. Berry (SEFC), and T. W. Pietsch (MCZ) for critically reviewing the manuscript and offering many helpful suggestions. The illustrations were done by Grady W. Reinert (SEFC). This study is part of a doctoral dissertation being prepared by the first author on the systematics of the lophiid angler fishes, and was supported in part by a Grant-in-Aid of Research from the Society of the Sigma Xi. This is Contribution Number 439 from the Southeast Fisheries Center, Miami, Fla. LITERATURE CITED Bradbury, M. G. 1967. The genera of Batfishes (Family Ogcocephalidae). Copeia 1967(2): 399-422.
64 BULLETIN OF MARINE SCIENCE, VOL. 26, NO.1, 1976 Le Danois, Y. 1973. La famille des Lophiidae Poissons pediculates Raplopterygiens) et sa repartition geographique. Bull. Mus. Nat!. Rist. Nat. Ser. 3, Ecologie Generale 15: 261-270. 1974. Etude Osteo-myologique et Revision Systematique de la Pamille des Lophiidae, (Pediculates Raplopterygiens). Mem. Mus. Nat!. Rist. Nat., Paris Ser. A, Zoo!. 91: iii + 127 pp. Radcliffe, L. 1912. New pediculate fishes from the Philippine Islands and contiguous waters. Proc. U.S. Nat. Mus. 42: 119-214. Regan, C. T. 1908. Report on the marine fishes collected by Mr. J. Stanley Gardiner in the Indian Ocean. Trans. Linn. Soc., London. 12: 217-255. ADDRESSES: (IHC) Systematic and Environmental Biology Laboratory, Hebert Center, Tulane University, Route 1, Box 46-B, Belle Chasse, Louisiana 70037. PRESENT ADDRESS: Dept. of Biology, Lafayette College, Easton, Pennsylvania 18042. (HRB) National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Center, 75 Virginia Beach Drive, Miami, Florida 33149.