ANNOTATED LIST OF THE SPECIES 325 Rio Negro to Rio Jurudé and Peruvian Amazon 15721, 1, 202 mm., Iquitos, Allen, September, 1920.
454. STERNARCHOGITON PORCINUM Eigenmann and Allen, sp. nov. Plate Xeval fig 1 15740, 1, 300 mm., type, Rio Huallaga, Yurimaguas, Allen, November, 1920. 15722, 1, paratype, 186 mm., Iquitcs, Allen, September, 1920. Not unlike its congener, S. natterer’, differing, however, in several dimensions, in the extent of the anal fin; colors also differing considerably. Head about 9 in the length; depth 8.5; anal rays about 200; origin of the anal fin beneath the middle of the opercle.
Snout 3.5 in the length of the head; interorbital width 5 in the head length; eye about 7 in the snout, and smaller than usual among a small-eyed family; scales large, about 4—5 series above the lateral line, pores between the scales toward the back, the scales much higher than long; pectoral fin not as long as the head. Sides straw-colored, the back dark; posterior half of the pectoral fins and the distal half of the anal rays very dark, their basal halves without dark pigmentation. The name in allusion to the strong inclusion of the lower jaw within the upper. Genus 182: OKEDEMOGNATHUS Myers OedemognathusMyers,1936,Proc.Biol.Soc.Wash.,XLEX,115.
Type: Oedemognathus exodon Myers Iquitos and lower Peruvian Amazon A single specimen, 92 mm. in length, collected by Morris at Iquitos, was described as a new genus and species by Eigenmann and Allen (the present paper). In 1936 a similar fish, 202 mm. long, was found and described by Dr. G. 8S. Myers from collections made by Mr. William G. Scherer in 1935 for the U. S. National Museum, under the present name.
Caudal fin and dorsal filament present; snout very short; teeth in both jaws strong, all those of the upper jaw fixed on the everted lip; those of the lower jaw in part antrorse, in part located in the mouth and retrorse; area in front of the dorsal filament naked. Similar to Porotergus and Sternarchogiton, but with everted teeth. Maxillary oblique, gape short, not quite reaching the vertical from the eye. Our specimen differs from the type apparently only in the following particulars:
The eye, while minute, is not covered; that the mandibular teeth are contained within the mouth.
455. OEDEMOGNATHUS EXODON Myers Plate XV, figs. 2 and 3 Oedemognathus exodon Myers, 1936, Proc. Biol. Soe. Wash., XLIX, 115, one, Pebas, Scherer collection, 15421,1,92mm.,tobaseofcaudal,Iquitos,Morris,1922.
326 FISHES OF WESTERN SOUTH AMERICA The complete identity of our specimen with the type of Oe. exodon is not certain in the absence of scale counts and measurements, and considerable doubt may be entertained from the fact that the type has 193 or more anal rays, while our specimen has but 163; the anal is conspicuously elevated in our specimen (to about three-fifths the greatest body depth) and even more so in the type (two-thirds). The dimensions of the former are much as we might expect in a juvenile of the latter.
Head 7.5; depth at the pectoral fin equal to the length of the head; A. 168, its origin under the angle of the preopercle, much in advance of the pectoral fin; anus under the eye; width of the head about 3 in its length; interorbital greatly arched; eye without free orbital margin, 3.5 in the snout, 9.33 in the head; scales on sides above the anal fin-musculature larger, about 70 in a longitudinal series; the back in front of the dorsal filament naked, with minute pits; scales covering the anal musculature minute.
Naked portion of the back dusky; sides light, no distinct markings. In general appearance this is a Porotergus, and so closely resembles Sternarchogiton natterer’ (Steindachner) that it would be easy to mistake it for an abnormal specimen of that species. The head, however, is decidedly different, the eyes are less elevated, the mouth different, and the teeth unique.
Known only from Iquitos and the nearby Rio Ambyiacu region. Genus 183: ADONTOSTERNARCHUS Ellis Adontosternarchus Ellis, 1913, Mem. Carnegie Mus., VI, 155. Type: Sternarchus sachsi Peters Throughout Amazons, the Madeira, and the Orinoco Characterized by the heavy lower jaw into which the pointed upper jaw fits by a V-shaped groove, somewhat as in the case of the whalebone whale; edentulous. KEY TO THE SPECIES OF THE GENUS ADONTOSTERNARCHUS a. Without longitudinal stripes; colors variegated, at least while in fresh condition........ sachsi aa. With a pale longitudinal striping.......... eee, Me ene egearety ee Pee dr anes balaenops 456. ADONTOSTERNARCHUS SACHSI (Peters) SternarchussachsiPeters,1877,Monatsb.Akad.Wiss.Berlin,473,fig.4,Venezuela; Eigenmann and Eigenmann, 1891, Proc. U. 5. Nat. Mus., XIV, 62. SternarchogitonsachsiKigenmannandWard,1905,Proc.Wash.Acad.Sci.,VII,165; HKigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 448. AdontosternarchussachsiEllis,1913,Mem.CarnegieMus.,VI,156,lowerAmazons; Fowler, 1939 (1940), Proce. Acad. Nat. Sci. Phila., XCI, 278, one, 154 mm., Contamana. Rivers Orinoco, upper and lower Amazon, Madeira 15719, 4, the largest about 195 mm., Iquitos, Allen, September, 1920. These specimens while fresh show considerable variegation in pattern, no trace of a longitudinal striation; distal half of the pectoral fin, and the distal portion of
ANNOTATED LIST OF THE SPECIES 327 the anterior half of the anal, together with its entire posterior part, dark; a dark spot above the gill-opening.
457. ADONTOSTERNARCHUS BALAENOPS (Cope) Sternarchus balaenops Cope, 1878, Proc. Amer. Phil. Soc., XVII, 682, Peruvian Amazon; Eigenmann and EKigenmann, 1891, Proc. U.S. Nat. Mus., XIV, 62. SternarchellabalaenopsEKigenmannandWard,1905,Proc.Wash.Acad.Sci.,VIT,164; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 448; Ellis, 1913, Mem. Carnegie Mus., VI, 152.
Peruvian Amazon Described by Cope, and not collected since his time. Differing from S. sachsi in the color, having ‘‘a pale dorsal band which reaches the dorsal thong, and a pale narrow band on each side near the dorsal band.” Subfamily: RHAMPHICHTHYINAE Genus 184: RHAMPHICHTHYS Miiller and Troschel Gymnotus (in part) Linnaeus, 1766, Syst. Nat., ed. xu, 427. Rhamphichthys Miller and Troschel, 1849, Horae Ichth., III, 15; Rigenmann and Eigenmann, 1891, Proc. U. S. Nat. Mus., XIV, 62; EKigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 449; Eigenmann,1912,Mem.CarnegieMus.,V,435; Ellis, 1913, Mem. Carnegie Mus., VI, 137.
Type: Gymnotus rostratus Linnaeus The Guianas to Peru and La Plata Snout long and tubular; without teeth; body greatly elongate and compressed ; no caudal fin; anus in front of the vertical from the eye; origin of anal fin forward of the vertical from the gill-opening; body entirely scaled, scales minute and cycloid; caudal appendage large and scaled; eyes small and overgrown by the skin; mouth small.
KEY TO THE SPECIES OF THE GENUS RHAMPHICHTHYS a. Snout longer, the postorbital part of the head 3 in the total length of the head; the eye much farther from the base of the pectoral than from the snout............. _....rostratus aa. Postorbital part of head 2.4 in head length; eye equidistant from snout and pectoral basis Re SR Fe Re Meo Se! arepand nee Stee SM aera c In eel emer te ay Pel ok eens marmoratus 458. RHAMPHICHTHYS ROSTRATUS (Linnaeus) Gymnotus Gronow, 1754, Mus. Ichth., no. 73.
GymnotusrostratusLinnaeus,1766,Syst.Nat.,ed.xii,I,428. CarapusrostratusCuvier,1817,RegneAnim.,IT,237. RhamphichthysrostratusMillerandTroschel,1849,HoraeIchth.,IIT,15; Ginther, 1870, Cat. Fish. Brit. Mus., VIII, 5; Jigenmann and Ward, 1905, Proc. Wash. Acad. Sci., VII, 168; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 449; Ellis, 1913, Mem. Carnegie Mus., VI, 137.
328 FISHES OF WESTERN SOUTH AMERICA The Guianas and the Amazons 15608, 2, the longer 561 mm., Iquitos, Allen, September, 1920. 15809, 1, 405 mm. (tail broken), Iquitos, Allen, September, 1920. 459. RHAMPHICHTHYS MARMORATUS Castelnau RhamphichthysmarmoratusCastelnau,1855,Anim.Amér.Sud,Poiss.,86,pl.xlvi,fig.2,Uruguay; EKigenmann and EKigenmann, 1891, Proc. U.S. Nat. Mus., XIV, 62; Kigenmann and Ward, 1905, Proc. Wash. Acad. Sci., VII, 168; Jigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 449. RhamphichthyspantherinusCastelnau,1855,Anim.Amér.Sud,Poiss.,86,pl.xlvi,fig.3,lakenear RioUcayali; Giinther, 1870, Cat. Fish. Brit. Mus., VIII, 5; Cope, 1878, Proc. Amer. Phil. Soc., XVII, 682, Peruvian Amazon, Steindachner, 1880, Denksch. IIx. Akad. Wiss. Wien, XLII, 38, Ucayali. Rhamphichthys lineatus Castelnau, 1855, Anim. Amér. Sud., Poiss., 87, pl. xlvii, fig. 1, tributary of RioUcayali; Kaup, 1856, Cat. Apod., 130, fig. 5.
Gymnotus rostratus Steindachner, 1868, Sitzb. Kx. Akad. Wiss. Wien, LVIII, 8, in part. Rhamphichthys rostratus (in part) Ellis, 19183, Mem. Carnegie Mus., VI, 187. Rio Orinoco and the Guianas southward to La Plata 15423, 1, broken, the piece 330 mm., Iquitos (?), Allen, 1920. Much resembles R. rostratus, the postorbital part of the head greater, however, 2.4 in the length of the head, the eye bisecting the distance between the snout and pectoral basis. In size the specimen evidently lies between the extreme lengths of the three specimens of R. rostratus, in all of which the postorbital part of the head is one-third the total length of the head. The elongation of the snout places it here rather than with rostratus.
Subfamily: GYMNOTINAE Genus 185: GYMNOTUS Linnaeus GymnotusLinnaeus,1758,Syst.Nat.,ed.x,246; Cuvier, 1817, Régne Anim., II, 235; Giinther, 1870, Cat. Fish. Brit. Mus., VIII, 10; Bigenmann and Ward, 1905, Proc. Wash. Acad. Sei., VII, 174; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, HT, 450; Ellis (in Eigenmann), 1912, Mem. Carnegie Mus., V, 425; Ellis, 1913, Mem. Carnegie Mus., VI, 116 (contains a very comprehensive bibliography of the genus); Eigenmann, 1922, Mem. Carnegie Mus., LX, 171. Type: Gymnotus carapo Linnaeus Range that of the one species No frontal fontanel; anal basis not continuing as a false caudal fin around the end of the tail, which is terminal and cylindrical; body scaled, teeth conical, a single row in each jaw; not electric.
ANNOTATED LIST OF THE SPECIES 329 460. GymMNnotus CARAPO Linnaeus Carapo Marcgrave, 1648, Hist. Rer. Nat. Bras., 170. GymnotuscarapoLinnaeus,1758,Syst.Nat.,ed.x,I,246; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 450; Eigenmann, 1912, Mem. Carnegie Mus., V, 425; Ellis, 1913, Mem. Carnegie Mus., VI, 117, fig. 2. GymnotuscarapusEigenmannandWard,1905,Proce.Wash.Acad.Sci.,VII,175. Gymnotus fasciatus Pallas, 1769, Spic. Zool., VII, 35. CarapusfasciatusCuvier,1817,RegneAnim.,II,237; Steindachner, 1868, Sitzb. IKIk. Akad. Wiss. Wien, LVIII, 13; Giinther, 1870, Cat. Fish. Brit. Mus., VIII, 9; Cope, 1871, Proc. Acad. Nat. Sci. Phila., XXIII, 257, R. Ambyiacu; Cope, 1878, Proc. Amer. Phil. Soc., XVII, 682; Boulenger, 1887, Proc. Zool. Soc. London, 282. GymnotusbrachiurusBloch,1786,Ausl.Fische,IT,61,pl.157,fig.1. CarapusbrachyurusCuvier,1817,ReégneAnim.,II,237. Sternopygus carapo Eigenmann and Eigenmann, 1891, Proc. U.S. Nat. Mus., XIV, 62. Giton fasciatus Eigenmann and Ward, 1905, Proc. Wash. Acad. Sei., VII, 177. Guatemala southward to La Plata, Andes eastward 15420,1,about390mm.,Iquitos,Allen,November,1920. 15718,3,25,185,and205mm.,Iquitos,Allen,November,1920. 15724, many, 190-295 mm., creek, Yurimaguas, Allen, November, 1920. 15992, 7, 142-247 mm., brooks, Rio Itaya, Allen, September, 1920. In the smallest the crossbands are fully developed on the body muscles, but do not extend over the muscles of the anal fin. In the middle-sized ones the bands extend to the anal, and in the largest they are broken into irregular double rows of spots on the back, remaining most completely outlined on the musculature of the anal fin. The lateral bands are most conspicuous in the smaller specimens from Yurimaguas, and remain the brightest on the tail. The occurrence of the brightest coloration in the swift, rocky streams of the piedmont and mountain sections is consistent with other cases previously mentioned. The coloration and markings of this species are much the brightest of all the members of the family, and quite naturally was the first to attract the attention of European naturalists among the five Linnaean species.
Subfamily: ELECTROPHORINAE Genus 186: ELECTROPHORUS Gill Gymnotus(inpart)Linnaeus,1766,Syst.Nat.,ed.xn,427. Electrophorus Gill, 1864, Proc. Acad. Nat. Sci. Phila., XVI, 151; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 450; Eigenmann, 1912, Mem. Carnegie Mus., V, 424; Ellis, 1913, Mem. Carnegie Mus., VI, 114. (Excellentbibliographyofolderreferences).
330 FISHES OF WESTERN SOUTH AMERICA Type: Gymnotus electricus Linnaeus Most of Brazil and Peruvian Amazon northward Cylindrical in form; scaleless; frontal fontanel wanting; the basis of the anal fin continued around the tail, constituting a pseudo-caudal; much of the hypaxial musculature of the tail modified into an electric organ on each side. 461. ELECTROPHORUS ELECTRICUS (Linnaeus) GymnotuselectricusLinnaeus,1766,Syst.Nat.,ed.xii,I,427; Miiller and Troschel, in Schomburgk, Reisen, 1848, III, 639; Steindachner, 1868, Sitzb. KKK. Akad. Wiss. Wien, LVIII, 14; Giinther, 1870, Cat. Fish. Brit. Mus., VIII, 10, and many authors. Electrophorus electricus Gill, 1864, Proce. Acad. Nat. Sei. Phila., XVI, 151; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, II, 450; Eigenmann, 1912, Mem. Carnegie Mus., V, 424; Ellis, 1913, Mem. Carnegie Mus., VI, 114, fig. 1.
All of Amazonia northward to Venezuela, Guianas 15419, 4, 76-130 mm., Pto. Bermudez, R. Pichis, Allen, July, 1920. This is the most western and most elevated record for the species. Not especially prevalent in most of our area. Not nearly so greatly feared by the inhabitants as the urinophilous Pygidiids or the piranha. Known to the inhabitants of eastern Peru as the angwila electrica, at least among the educated class. The name puraqué is given by Cox, and poraqué by Guenther (p. 175). Haseman’s spelling is purakee.
This is the electric eel of fame, and the subject of numerous researches from the time of Faraday to the present, with numerous articles from the pens of zoologists and physicists alike. Many papers are summarized in Ellis’s monograph of 1913 (p. 162). Witnesses have had all sorts of experiences with the fish, and conflicting reports are found in the literature as to the effects of the shock, and as to the place in Nature which the species occupies.
Im Thurn (p. 137) says that the fish is numerous in the region of the penal colony of French Guiana, where he experienced a very painful shock from one which the Indians had poisoned. Herndon (p. 344) characterizes the discharge as being unpleasant, but not painful. He says that persons differ in their susceptibility, and that Captain Lee was unable to feel it at all, while a certain lady was entirely overcome by it. He relates further that a Mr. Norris saw a horse drinking from a tub in which a live Electrophorus was kept, and that such a shock was given that the horse was jerked quite off its feet. Up de Graff (p. 245) relates the incredible experience of being unable to cut the head off the fish— the shock would only knock the machete out of his hand, and paralyze his arm!
Senor Paez (p. 117) can always be depended upon for a good story. He tells that an electric eel was found among the catch in a seine. A boy was dragging it along by a rope, and unintentionally drew it across the carcass of a cayman recently killed. An electric discharge happened to take place at that moment, and the cayman ‘‘opened his huge jaws and closed them with a loud crash.”’ Eubank (p. 138) like others tells of the ‘““gymnotus”’ being kept in captivity,
ANNOTATED LIST OF THE SPECIES 331 among them one of two feet in length which had been a pet or a curiosity in a cistern of a monastery cloister for fifteen years.
In the spirit of Faraday’s experiment in which he used the discharge to ignite gunpowder or to charge Leyden jars, Coates and Cox have resumed physical studies of the fish with the more refined methods of modern apparatus. Cox (1938) has shown from his field and laboratory studies that the minor electroplax of the fish differs from the major electric organ in that it delivers a low, constant discharge while swimming, which may be either a warning or a protection. He finds also that the fish not only discharges electricity, but is sensitive to it as well. He was able to use a hand-generator, with the positive and negative plates in the water, as a lure, the fishes being attracted to the positive pole. These workers have made studies of the character of the electric discharge, its control, its volume, duration, and like matters. They have been able to register voltages up to nearly 600, and wattages up to 1000, but over such brief periods of time that the filaments of lamps could not reach incandescence.
Haseman’s experiences may help to explain the degrees of potency of the electric discharge (1911b). An Indian had shot a purakee five feet long, with bow and arrow, the same length as the one which Herndon discusses. _Haseman swam after the specimen and pulled it ashore. While the fish yet had the tail in water, he was able to pass his hand over it repeatedly. The shock was acute, but not overpowering. Then while removing it with a copper dipnet from the water, “I received all its voltage, and fell helpless in the moist sand. A series of terrible shocks continued as long as the eel remained on my bare legs, and I could not let go the dipnet. The Indian relieved me by pulling the eel away by means of the arrow.”” Haseman is convinced that the electric organ is nothing more than a protection, for he has seen no evidence of its ever being used offensively for taking prey. Ellis’s studies of the Gymnotid family led him to regard the lower Amazon as the center of its dispersal. The present report, in which we list about the same number of species for Peruvian waters as Ellis lists for all South America, would encourage the view that the center of dispersal is farther up the Amazon than he had reason to believe (1913).
Order SYMBRANCHIA Family XIII: Symbranchidae Genus 187: SYMBRANCHUS Bloch Synbranchus Bloch, 1795, Ausl. Fische., IX, 86; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 450. Symbranchus(correctedspelling)mostauthors; Higenmann, 1912, Mem. Carnegie Mus., V, 442; Eigenmann, 1922, Mem. Carnegie Mus., LX, 177.
Type: Synbranchus marmoratus Bloch Range that of the one species Anguilliform, sealeless; tail shorter than trunk; right and left gill-membranes joined in midventral line, forming a single, small, median ventral gill-aperture.
332 FISHES OF WESTERN SOUTH AMERICA 462. SYMBRANCHUS MARMORATUS Bloch Synbranchus marmoratus Bloch, 1795, Ausl. Fische, IX, 87, pl. 418; Miller and Troschel, 1848, in Schomburgk, Reisen, III, 640; Gunther, 1870, Cat. Fish. Brit. Mus., VIII, 15; Jordan and Evermann, 1898, Bull. U.S. Nat. Mus., XLVIT, 342; Kigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 450. Symbranchus marmoratus Cope, 1871, Proc. Acad. Nat. Sei. Phila., XXIII, 290, Rio Ambyiacu; Cope, 1878, Proc. Amer. Phil. Soc., XVII, 673, near Pebas; Kigenmann, 1912, Mem. Carnegie Mus., V, 443; Bigenmann, 1922, Mem. Carnegie Mus., LX, 177. Cuba and Mexico to Peru and Rio de la Plata 16162, 14 (1, 193 mm., 13 juvenile, about 45 mm.) creek, Yurimaguas, Allen, November, 1920. A species with wider distribution than any other South American freshwater form.
Order ISOSPONDYLI Family XIV: Engraulidae Genus 188: LYCENGRAULIS Gunther Lycengraulis Giinther, 1868, Cat. Fish. Brit. Mus., VIT, 385; Eigenmann and Eigenmann, 1891, Proc. U. 8. Nat. Mus., XIV, 63; Higenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 452. Type: Engraulis grossidens Cuvier Marine, Guiana to Rio de Janeiro, entering rivers; the Amazons Differing from other anchovies in the possession of unequal teeth, partly canine. 463. LycCENGRAULIS BATESID Giinther Lycengraulis batesii Giinther, 1868, Cat. Fish. Brit. Mus., VII, 399; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 452. Engraulis iquitensis Nakashima, 1941, Bol. Mus. Hist. Nat. Lima, V, 62. Rio de Para to cis-Andean Peru 16151,2,145and215mm.,Yurimaguas,Allen,November,1920. 16152,2,143and198mm.,Gosulimacocha,R.Morona,Allen,October,1920. 16153, 1, 162 mm., R. Paranapura, Yurimaguas, Allen, November, 1920. The species appears to be completely adjusted to fresh waters, although its nearest relatives are partly marine.
Nakashima’s specimens, fide G. 8. Myers, are undoubtedly this species. Genus 189: AMPLOVA Jordan and Seale AmplovaJordanandSeale,1925,Copeia,no.141,31,balboae; Myers, 1940, Proc. Cal. Acad. Sci., (4), XXIII, 438.