FLORIDA STATE MUSEUM
BIOLOGICAL SCIENCES Volume 3 Number 4
STUDIES ON FISHES OF THE FAMILY CHARACIDAE NO. 16A NEW HYPHESSOBRYCON FROM COSTA RICA
James E. Bohlke
UNIVERSITY OF FLORIDA Gainesville 1958
The numbers of THE BULLETIN OF THE FLORIDA STATE MUSEUM, BIOLOGICAL SCIENCES, will be published at irregular intervals. Volumes will contain about 300 pages and will not necessarily be completed in any one calendar year.
William J. Riemer, Editor
, Roland F. Hussey, Associate Editor
All communications concerning purchase or exchange of the publication should be addressed to the Curator of Biological Sciences, Florida State Museum, Seaglc Building, Gainesville, Florida. Manuscripts should be sent to the Editor of the BULLETIN, Flint Hall, University of Florida, Gainesville, Florida.
Published 10 November 1958
Price for this issue if. 1 -1
STUDIES ON FISHES OF THE FAMILY CHARACIDAE. NO. 16.A NEW HYPHESSOBRYCON FROM COSTA RICA
James E. Bohlke 1
Synopsis: A new tetra of the genus Hyphessobrycon is described from the Tortuguero River in Costa Rica. While it is thought to be really close to none of the other known members of the genus, Hyphessobrycon compressus (Meek) and H. milleri Durbin are probably its closest allies. The species is also compared with the rhoadsiine, Rhoadsia eigenmanni (Meek), from near the same geographic locality.
The characid described as new in this paper is part of a collection of fishes recently made under the direction of A. F. Carr in Costa Rica, while Carr, as Principal Investigator, was engaged on National Science Foundation Project G-1684 (The Ecology and Migrations of Sea Turtles). David K. Caldwell is studying the greater portion of die fishes collected, but the characids were sent to me for determination. I wish to thank Caldwell for supplying me with the field data for the collection that included the new species.
Tortuguero, the place where the fish were collected, is located on the northeastern coast of Costa Rica a short distance from the Nicaraguan border.
The following abbreviations are used in the text: UF (University of Florida Collections), ANSP (Academy of Natural Sciences of Philadelphia), CNHM (Chicago Natural History Museum).
Hyphessobrycon tortuguerae new species
Holotype.UF 5741, an adult male, 39.0 mm. in standard length, collected by L. H. Ogren from the Tortuguero River (Lagoon) at Tortuguero, 2 miles from ocean inlet, Costa Rica; collected by cast net near a submerged brush pile and on an incoming tide; slight current, but collection from a sheltered area; depth of 3% feet, but dropping sharply to 20 or 25 feet; bottom of sandy muck; water brackish due to strong outflow of fresh water from river; water of light tea color; vegetation of water hyacinths only; collected 3 September 1956. Original field number 157.
1 James Bohlke is Associate Curator of the Department of Ichthyology and Herpetology at the Academy of Natural Sciences of Philadelphia. This study was carried out while the writer was serving as Collaborator on the staff of the Florida State Museum. Manuscript submitted 25 April 1958.Ed.
SI O t .2
Figure 1.Holotype of Hyphessobrycon tortuguerae, UF 5741, 39.0 mm. Photograph by A. Delwin Warden.
Hyphessobrycon tortuguerae (fig. 1) is one of the deep-bodied, greatly compressed species of the genus. The body is deepest at the origin of the dorsal; the depth at this point goes 2.7 times in the standard length. The caudal peduncle is slender and short, its length little greater than its least depthleast depth goes 9.5 times, and length goes 8.0 times, in the standard length.
Length of head goes 3.4 times into standard length, live diameter goes 2.7, snout length 4.1, bony interorbital width 3.9, and length of upper jaw 2.6 times into head length. The eye does not enter the dorsal profile; its diameter is much greater than the length of the snout. The snout is slightly, but constantly, shorter than the interorbital width. The maxillary extends back beyond the front margin of the eye, but not to a vertical with the fore margin of the pupil. The mouth is terminal; the lower jaw protrudes.
Paratypes.UF 5S36, 3, 24.2 to 24.8 mm., ANSP 80986, 2, 26.8 and 27.5 mm., ANSP 80987, 1 stained specimen, 27.5 mm.; all collected with the holotype.
Diagnosis. Maxillary teeth rather numerous, 9 or 10; lateral scales 35 or 36; two humeral spots, but no dorsal, caudal, or anal blotches; 6 teeth in the inner premaxillary series.
Description.Because of the great difference in size between the holotype and paratypes, the following description is of the holotype only. A statement of the obvious deviations from this description shown by the paratypes is presented later. Proportions and counts for the holotype and four paratypes are presented in table 1.
BOHLKE: FAMILY CHARACIDAE
Fontanels are moderately developed and completely separate frontal and parietal bones except for a strong bridge between them. The lateral margins of both fontanels are straight lines; their widths taper evenly from the widest point at the base of the occipital process to the anterior ends of the frontal bones. The great suborbital does not nearly cover the cheek and leaves broad free areas both below and behind. Three postorbitals are present; all leave rather broad, naked areas free behind them. Gill rakers are longthe longest about equal to die pupilslender, close-set; there are 9-f-17 on the first gill arch.
Teeth are essentially tricuspid on all jaw bones. Some of the smaller ones on the premaxillary and the posterior parts of the maxillaries and mandibles lack lateral shoulders and are conical. Premaxillary teeth on one side (the other side is injured) are in two series, with three in the outer row, six in the inner. There are 9 or 10 teeth along more than half the free edge of the maxillary. On the mandibles there are five large teeth in front, followed by six abruptly smaller teeth along the sides. The maxillary ends postero-dorsally in a rounded point.
The origin of the dorsal fin is equidistant from the tip of the snout and the base of the caudal; its distance from the tip of snout goes 1.9 times into standard length. The dorsal origin is distinctly in advance of that of the anal; a vertical with the base of the first anal ray falls slightly behind the mid-point of the dorsal base. The dorsal fin is pointed, its posterior margin nearly a straight line; the height of the fin goes 3.3 times in the standard length. The adipose dorsal fin is well developed, its origin is above the nineteenth or twentieth branched anal ray.
The pectoral and ventral fins are pointed; the former overlaps the latter, the latter overlaps the anal fin. The length of the pectoral goes 5.0, the length of the ventral 5.3, the snout to pectoral distance 3.7, the snout to ventral distance 2.3, and die snout to anal distance 1.7 times into the standard length. The anal fin is lobed anteriorly; the margin of the fin just behind the lobe is concave. The final un-branched and first five branched anal rays have tiny hooks; this is a male secondary sexual characteristic. The caudal fin is deeply forked; the lobes are slender and rounded.
The scales are cycloid, with few concentric ridges, and rather many radii on their exposed portions (4 to 7 radii counted on each of a small sample of scales from below the dorsal fin above midbody). Lateral scales number 36, of which 8 or 9 are perforated. Transverse scales between dorsal and ventral fins number ?14 (the count is uncer-
tain because of missing scales), and scales around the caudal peduncle number 14. The predorsal line is scaled. The caudal fin is scaleless, except at its base.
Coloration in Alcohol.The body, head, and fins are everywhere rather heavily sprinkled with melanophores. There is no lateral band save for the usual, fine, deep-lying line of intermuscular melanophores. There is no caudal spot, nor are bands or spots present on dorsal, pectoral, ventral, or caudal fins. A broad dark band is present down the center of the anal fin, the fin being lighter both proximally and distally. The top of the head and upper half of the postorbital part of the head are dark. There are two dark humeral spots with a lighter area between them; the anterior is narrow, vertically elongate, and crosses the second to fifth scales of the lateral line. The posterior humeral spot is more roundish, considerably more intense than the other, and is placed above the seventh to ninth scales of the lateral line.
Variation in the Pahatypes.Greatest depth of body goes 3.1 to 3.5, least depth of peduncle 9.8 to 10.7, length of peduncle 7.4 to 7.9, length of head 3.3 to 3.4, tip of snout to origin of dorsal En 1.9 to 2.0, snout to pectoral 3.4, snout to ventral 2.2 to 2.3, snout to anal 1.7, height of dorsal fin 3.1 to 3.2, length of ventral fin 4.8 to 5.1, and length of pectoral fin 5.0 to 5.6 times into the standard length.
Diameter of eye goes 2.5 to 2.6, length of snout 4.0 to 4.3, least width of bony interorbital 3.5 to 3.7, and length of upper jaw 2.5 to 2.7 times into length of head.
Fin ray and gill raker counts are summarized in table 2. Lateral scales number 35 or 36, of which 7 to 10 are perforated (I count 3 each of 7, 8, and 9 scales, and 1 of 10 scales). Outer premaxillary teeth number 2 to 4 (2 counts of 2 teeth, 5 of 3 teeth, and 1 of 4 teeth). Inner premaxillary teeth number 6 or 7 (one uncertain count of 7). There are 4 or 5 enlarged anterior mandibular teeth in front of the tiny lateral teeth. The stained 27.5 mm. specimen has 10 and 9 maxillary teeth, and three postorbitals on each side.
Coloration of the small paratypes is in general similar to that of the holotype, but the anterior humeral spot is darker so that the two spots are of about equal intensity. The longitudinal dark stripe on the anal fin is variously developed but is always apparent on the paratypes.
Relationships.The species may be distinguished from all other known members of the genus by the combination of characters given in the diagnosis. It appears to be more closely related to Hyphes-
BOHLKE: FAMILY CHARACIDAE
Htjphessobrycon tortuguerae: proportions (as thousandths of standard length) and fin hay counts of the holotype and fouk paratopes
UF 5836 (1 of 3) ANSP 80986 ANSP 80987 stained UF 5741 holotype
Standard length (mm.) 24.2 26.8 27.5 27.5 39.0
Greatest depth 310 284 316 320 372
Snout to dorsal 533 511 527 524 526
Snout to pectoral 293 295 291 291 273
Snout to ventral 455 440 444 444 431
Snout to anal 599 580 587 585 585
Depth of peduncle 101 093 102 102 105
Length of peduncle 126 134 129 127 124
Length of pectoral 186 179 193 200 200
Length of ventral 207 198 200 207 190
Height of dorsal 322 309 309 299
Length of head 298 300 295 296 291
Diameter of eye 116 119 116 116 108
Length of snout 074 075 073 069 071
Bony interorbital 085 082 082 085 074
Length upper jaw 120 112 120 120 110
Dorsal rays ii,9 ii,9 ii,9 ii.9 ii,9
Anal rays v,25 v,25 v,24 v,24 v,26
(left and right) U2 US i,12/i,13 i,13 i,12
(left and right) i,7 i,8 i,8 i,7 i,8
Caudal rays i,17,i U7;i U7,i i,17,i i,17,i
Htjpliessobrycon tortuguerae: fin ray and cill raker counts of
the seven type specimens
Bays Frequency Rakers Frequency
Dorsal ii.9 7 Upper limb 9 2
Anal v,24 2 10 5
v,25 3 Lower limb 17 5
v,26 2 00 2
Pectorals U2 7 Total count 26 2
i,13 7 27 3
Ventrals M 8 28 2
Caudal U7,i 7
sobrycon compressus (Meek) of Mexico and H. milleri Durbin of Guatemala than to others in spite of its lower lateral scale count, different coloration, and different gill raker counts. H. tortuguerae seems to be really close to none of the other species.
Because of the changes in dentition that rhoadsiine characids undergo during ontogeny, the new species was also compared with material of Rhoadsia eigenmanni (Meek) from Costa Rica. Loren P. Woods kindly lent me the following material of that species: CNHM 43150, 1, 56.7 mm. in standard length; La Junta, Costa Rica; collected by S. E. Meek; 8 April 1912; CNHM 7861, 3, 47.0 to 54.6 mm., same locality and collector, 17 April 1913. Bhoadsia eigenmanni is easily distinguished from the new Hyphessobrycon by its multicuspid premaxillary, mandibular, and upper maxillary teeth; the presence of only a single, posterior, humeral spot; die presence of a well-defined, horizontally elongate, caudal blotch; more numerous anal fin rays (iii or iv, 26 to 30 contrasted with v, 24 to 26); and more numerous scales (37 to 41 contrasted with 35 or 36).
Myers (in Eigenmann and Myers, 1929, p. 463) appended a footnote to the discussion of Bhoadsia eigenmanni, saying: "This species is very likely generically distinct from Rhoadsia, in which case it would go by the name Carlia eigenmanni." Aside from the different color pattern which marks R. eigenmanni as a very distinctive form, the Costa Rican rhoadsiine appears not greatly different from those of western Ecuador. It seems that all might well be maintained in the genus Rhoadsia.
I wish to thank the following members of the staff of the Florida State Museum for their aid in making this study possible: Arnold Grobman, Director, and J. C. Dickinson, Jr., Curator of Biological Sciences, who financed and helped expedite the work; Daniel M. Cohen, curator of fishes, and John C. Briggs, Associate in ichthyology, who aided me greatly with the collections, library, and various other types of assistance during my stay in Gainesville.
Eigenmann, Carl II., and George S. Myers
1929. The American Charaeidae. Mem. Mus. Comp. Zool. Harvard, vol. 43, pt. 5, pp. 429-574, 11 pis.
Contributions to the BULLETIN OF THE FLORIDA STATE MUSEUM may
be in any field of biology. Manuscripts dealing with natural history or systematic problems involving the southeastern United States or the Caribbean area are solicited especially.
Manuscripts should be of medium length12 to 200 printed pages. Examination for suitability is made by an Editorial Board.
The BULLETIN is distributed worldwide through institutional subscriptions and exchanges only. It is considered the responsibility of the author to distribute his paper to all interested individuals. To aid in this, fifty copies are furnished the author without cost.
Highly recommended as a guide is the "Style sheet for the scientific serial publications of the American Museum of Natural History," second edition, revised, 1953.
Manuscripts should be typewritten with double spacing, with ample margins, and on only one side of the paper. The author should keep a copy; the copy submitted must be the original. Tables, legends of figures, and all footnotes should be assembled separate from the text. Several legends or footnotes may be placed on a single sheet.
Illustrations, including maps and photographs, should be referred to as "figures" wherever possible. All illustrations are reduced to a maximum of iVt by 7V inches. The scales, wherever it is necessary, should be incorporated into the figure.
All references to literature should conform with the bibliographic style used in recent numbers of the BULLETIN. Spell out in full the titles of non-English serials.
Footnote material should be kept to a minimum. However, provide copy for a footnote detailing the title, affiliations, and address of the author (see recent numbers of the BULLETIN).
Manuscripts must be accompanied by a synopsisa brief and factual summary (not a mere description) of the contents and conclusions, which points out the presence of any new information and indicates its relevance. In it list all new organisms described and give their ranges; indicate all taxonomic changes proposed. The synopsis, written in full sentences, should be concise, but completely intelligible in itself without reference to the paper, thereby enabling the busy reader to decide more surely than he can from the title alone whether the paper merits his reading. The synopsis will be published with the paper, hence it does not replace the usual conclusions or summary sections. It will also serve as copy for the abstracting services.
Manuscripts and all editorial matters should be addressed to:
PREPARATION OF MANUSCRIPT
Editor of the BULLETIN Flint Hall
University of Florida Gainesville, Florida