ANNOTATED LIST OF THE SPECIES 157 head 1.8; depth at origin of pectoral in length 9.7; distance from last anal ray to base of middle caudal rays (length of peduncle) in length 3.6—4.0 (mode about 3.7; in rivulatum of the same size mode about 4.4); depth of peduncle in length 10 (6.8-8.0 in rivulatum). Contours gradually verging from depressed to compressed narrowly.
Eye minute, slightly forward on head, nearly concealed; snout 2.5 in head; interorbital space 3.6 in head; barbels short; narial barbels 2.2-2.6 in the head; maxillary barbels 1.8—2.0 in head; inferior maxillaries 2.1—2.4 in the head. Longest pectoral rays 1.2—1.3 in the head; first pectoral rays not prolonged, and short as last; origin of dorsal equidistant from end of opercle and base of middle caudal rays, directly above end of ventrals; end of dorsal basis above middle of anal; anal the larger with few accessory rays; ventrals very small; accessory rays of caudal not greatly pronounced; caudal truncate to subtruncate. Color in alcohol generally a plumbeous gray, shading into yellowish on sides and about the pectoral fins; small, faint spots not uniform nor well localized, especially numerous in the young.
The small, braided type-stream drains an extremely rugged and desolate country where it flows through a narrow canyon, its various small rami often disappearing beneath the rocky bed. At first impression the fishes were taken to be emaciated specimens of a form like taczanowskii, due to the nature of the stream. 117. Pyaiprum KNERII (Steindachner) Trichomycterus knerii Steindachner, 1882, Denksch. Kk. Akad. Wiss. Wien, XLVI, 21, pl. v, figs. 1-la,Canelos,Ecuador; non Kigenmann and Eigenmann, 1889, Proc. Cal. Acad. Sei., (2), I, 52: nonEigenmannandEigenmann,1890,Occ.PapersCal.Acad.Sei.,1,335. TrichomycteruskneriBoulenger,1887,Proc.Zool.Soc.London,278. Pygidium kneri Eigenmann, 1918, Mem. Carnegie Mus., VII, 314, pl. xlvi, figs. 1 and 2. Eastern Ecuador to Rio Meta Genus 56: PAREIODON Kner Pareiodon Kner, 1855, Sitab. KIX. Akad. Wiss. Wien, XVII, 160; Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sei., 1, 346; ‘igenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 401; Eigenmann, 1918, Mem. Carnegie Mus., VII, 343.
Centrophorus Kner, 1855, Denksch. Kix. Akad. Wiss. Wien, XVII, 161. Pariodon Giinther, 1864, Cat. Fish. Brit. Mus., V, 275.
Type: Pareiodon microps Kner Amazon basin The gill-membranes confluent with the skin of the isthmus; the gill-opening a narrow slit; opercle and preopercle with numerous small spines; mouth nearly terminal; a single series of pointed incisors in each jaw; nasal and mental barbels wanting; double maxillary barbels at angles of mouth; anal short; caudal forked.
158 FISHES OF WESTERN SOUTH AMERICA 118. PAREIODON MICROPS Kner Pareiodon microps Kner, 1855, Sitzb. KK. Akad. Wiss. Wien, XVII, 160; Cope, 1871, Proce. Acad. Nat. Sei. Phila., X XIII, 290, Ambyiacu; Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 346; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 401; Eigenmann, 1918, Mem. Carnegie Mus., VII, 344.
Trichomycterus pusillus Castelnau, 1855, Anim. Amér. Sud, Poiss., 50, pl. xxiv, fig. 4, Amazon, Araguay.
Rio Ambyiacu to the Araguay Subfamily: STEGOPHILINAE A group of Pygidiudae lacking mental and nasal barbels and with two maxillary barbels, the lower pair very small; mouth inferior and wide, with numerous rows of regular teeth; opercle and interopercle spinous, but pectorals soft-rayed; anal short; many species capable of some degree of parasitism. Genus 57: HENONEMUS Ejigenmann and Ward Henonemus Eigenmann and Ward, 1907, Ann. Carnegie Mus., IV, 118; Jigenmann, 1918, Mem. Carnegie Mus., VII, 345.
Type: Stegophilus intermedius EKigenmann and Eigenmann Amazons and La Plata Originally separated on the basis of the lack of a second maxillary barbel, later discovered, but minute. The genus retained on the ground of the negligible size of this barbel and the presence of but two opercular spines. Teeth numerous on jaws and lips; mandibulars transverse and united; separated from Stegophilus chiefly in having the caudal emarginate and in the reduced number of opercular spines; second maxillary barbel extremely small. 119. HeNoNEMUs PUNCTATUS (Boulenger) StegophiluspunctatusBoulenger,1887,Proc.Zool.Soc.London,279,pl.xxi,fig.4,Canelos. HenonemuspunctatusKigenmann,1910,Rept.PrincetonUniv.Exped.Patagonia,IIT,401; Eigenmann, 1918, Mem. Carnegie Mus., VII, 346, text figs. 23 and 24. Canelos, Ecuador; Santarem; Rio Madeira 15499, 3, 70-88 mm., Rio Morona, Allen, October, 1920. 15707, 1, Rio Huallaga, Yurimaguas, Allen, November, 1920. 15708, 2, 65 and 70 mm., Gosulimacocha, Rio Morona, Allen, October, 1920. 120. HENONEMUS MACROPS (Steindachner) Stegophilus macrops Steindachner, 1882 (1883), Denksch. KK. Akad. Wiss. Wien, XLVI, pl. vi, figs. 2 and 2a, Lake Manacapurt; Kigenmann and Higenmann, 1889, Proc. Cal. Acad. Sci., (2), I, 55; BKigenmannandEigenmann,1890,Occ.PapersCal.Acad.Sci.,I,344; Higenmann and Higenmann, 1891, Proc. U.S. Nat. Mus., XIV, 37.
ANNOTATED LIST OF THE SPECIES 159 HenonemusmacropsEKigenmann,1910,Rept.PrincetonUniv.Exped.Patagonia,III,401; Jigenmann,1918,Mem.CarnegieMus.,VII,346,textfig.22. Peru to Manacapurti 15705, 1, 34 mm., Yurimaguas, Allen, November, 1920. Hitherto known only from the types, in the Vienna Museum. Genus 58: PSEUDOSTEGOPHILUS Eigenmann and Eigenmann PseudostegophilusEigenmannandEKigenmann,1889,Proc.Cal.Acad.Sci.,(2),II,54; Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 341; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 400; Eigenmann,1918,Mem.CarnegieMus.,VII,349. Type: Stegophilus nemurus Giinther Upper Amazon and Mamoré Differing from Henonemus in having the opercle provided with four or five spines directed caudodorsally; the interopercle with spines directed caudoventrally ; eye 3.5-5.0 in the head; separated from Homodiaetus by the deeply forked caudal fin.
121. PSEUDOSTEGOPHILUS NEMURUS (Ginther) StegophilusnemurusGiinther,1869,Proc.Zool.Soc.London,429,PeruvianAmazon. Pseudostegophilus nemurus Eigenmann and Eigenmann, 1889, Proc. Cal. Acad. Sei., (2), II, 54, MaranonorUcayah; Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 341; Eigenmann, 1918, Mem. Carnegie Mus., VII, 350, pl. xliv, fig. 5. Upper Amazon to Rio Mamoré 15716,1,538mm.,Inahuaya,RioUcayali,Allen,August,1920. 15969,2,57and67mm.,Iquitos,Morris,1922. Genus 59: ACANTHOPOMA Liitken AcanthopomaLiitken,1891(1892),Vidensk.Meddel.Naturh.Foren.Kj6benhavn,53,fig.,annectens; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 401; Eigenmann,1918,Mem.CarnegieMus.,VII,354,pl.xxxvil. Type: Acanthopoma annectens Litken Rio Huallaga, known only from the single type specimen Gill membranes united across the isthmus in a free fold, as in Stegophilus. Unhke Stegophilus, Henonemus and Pseudostegophilus in not having the gillopening so greatly reduced.
122. ACANTHOPOMA ANNECTENS Litken Acanthopoma annectens Liitken, 1891 (1892), Vidensk. Meddel. Naturh. Foren. Kjébenhavn, 53, fig., Huallaga;
160 FISHES OF WESTERN SOUTH AMERICA Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 401; Eigenmann,1918,Mem.CarnegieMus.,VII,355,fig.28.
Rio Huallaga Liitken considers this species as an intermediate between the Stegophilines and Pygidium.
Genus 60: APOMATOCEROS Eigenmann Apomatoceros Eigenmann, 1922, Bijd. Tot de Dierk., X XII, 113, pls. iii and iv, figs. 1-9. Type: Apomatoceros alleni Eigenmann Peruvian Amazons Near Acanthopoma, but lacking the opercular spines; caudal furecate; upper jaw widened so as to enclose the short, narrow, lower jaw; gill-membranes united with the isthmus, except for a broad, free membrane.
123. APOMATOCEROS ALLENI Eigenmann Apomatoceros allent Figenmann, 1922, Bijdr. Tot de Dierk., XXII, 118, pls. i and iv, figs. 1-9. Rio Morona and Maranon First taken on the extreme border of the Amazonian flood plain within view of the foothills of the Andes. Dr. G. 8. Myers (letter) states that it has been rediscovered far down the Maranon at Pebas, by Mr. Wm. G. Scherer. 15500,1,146mm.,type,RioMorona,Allen,October,1920.
H. 8; depth 9; depth of head 16; eye 5.33 in head; interorbital equals snout plus half the eye diameter; P. 11 in the length; upper caudal lobe equals head, lower slightly longer. Depth of caudal peduncle 2.4 in its length. D. 9; A. 8; base of anal nearly double that of dorsal; compressed behind pectorals, greatly compressed forward, pectorals nearly horizontal.
Mouth very large, subcircular, upper jaw flexible, curling inward, prolonged backward to near tips of interopercular spines; terminal barbel of the maxillary reaching tips of interopercular spines, lower barbel very small, scale-like in shape; lower jaw firm, not reaching forward to middle of eye; upper jaw evidently elastic and expansible into a disk for attachment. Seven very regularly arranged, concentric series of teeth in upper jaw; shorter rows interpolated between these near the symphysis to a total of eleven, the number of rows decreasing to four at the end of the premaxillary, only the outer four rows continued across the middle, the others interrupted in the middle by a naked area; four rows of similar teeth in the lower jaw, those of the two rami separated by a considerable space free of teeth. Gill-membranes united and joined to the isthmus, but with a wide, free membrane across the isthmus. Distance between the anterior nares more than twice the distance between the posterior. A median, dermal keel from the base of the last ventral ray to between the tips of the pectorals. Interopercle with a series of five straight spines; opercular spines wanting.
ANNOTATED LIST OF THE SPECIES 161 A black spot on the nape, a narrow black band across the base of the caudal, a broad, silvery lateral band, otherwise translucent. The alimentary canal is a thin-walled tube, containing many fish-seales toward the end. Subfamily: VANDELLIINAE A group of Pygidiidae allied to the preceding subfamily in the lack of nasal and mental barbels, and differing in that the rows of lower teeth are in disconnected right and left rami, not transverse, and not strong; the mouth narrow; teeth few, slender, pointed.
Genus 61: VANDELLIA Cuvier and Valenciennes Vandellia Cuvier and Valenciennes, 1846, Hist. Nat. Poiss., XVIII, 386, pl. 547; Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 344; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, ITT, 401; Zigenmann,1918,Mem.CarnegieMus.,VII,358.
Type: Vandellia cirrhosa Cuvier and Valenciennes Upper Amazonia to Orinoco, Mamoré, Apuré, L. Hyanuary Characterized, with Urinophilus, by great elongation; small, inferior mouth; a few teeth in middle of upper jaw; often peculiar clawed teeth on the extremity of the maxillary; mandibular rami separated by a wide membrane; opercular spines directed caudo-dorsally, the interoperculars caudo-ventrally; gill-opening small; origin of ventrals nearer to caudal than to the snout; origin of anal back of dorsal; size of head and arrangement of spines would seem to adapt these fishes to a life of parasitism, or at least to intrusive habits; the intestine short, straight, and very distensible as in blood-sucking forms. The toothed mawxillaries are almost unique in this subfamily, among all siluroids. The mandibles lack teeth in one substantial group of species, and these Eigenmann (1918 c) has retained as the genus Vandellia, at least provisionally, and until the types of V. cirrhosa can be examined ; the name Uvrinophilus is provisionally applied to the toothed species until and unless cirrhosa is found to have the mandibular teeth. They are certainly wanting in V. plazat.
124. VANDELLIA PLAZAI Castelnau Vandellia plazavi Castelnau, 1855, Anim. Amér. Sud, Poiss., 51, pl. xxvii, fig. 1, probably Rio Ucayal; EigenmannandEigenmann,1890,Oce.PapersCal.Acad.Sci.,I,345; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 401; Eigenmann,1918,Mem.CarnegieMus.,VII,362,textfig.30.
Peruvian and Middle Amazons Genus 62: URINOPHILUS Eigenmann Vandellia (in part) Cuvier and Valenciennes, 1846, Hist. Nat. Poiss., XVIII, 386, pl. 547. Urinophilus Eigenmann, 1918, Mem. Carnegie Mus., VII, 358; Eigenmann,1920,Science,LI,441.
162 FISHES OF WESTERN SOUTH AMERICA Type: Vandellia sanguinea Eigenmann The characters of the genus as indicated under the preceding. 125. URINOPHILUS DIABOLICUS Myers Urinophilus diabolicus Myers, 1927, Bull. Mus. Comp. Zool., LXVIIT, 132. Upper Amazon 17701,1,type,47mm.,Iquitos,Allen,September,1920.
Called carnero by the inhabitants; taken from the belly of a doncella (Pseudoplatystoma), where it had penetrated half-way inside through the body wall, and not by a natural opening. Much distended with blood; color black, partly with the contents, while fresh.
Much less elongate than U. sanguineus and U. erythrurus; somewhat faded in alcohol to a brownish color, with finer, dark brown chromatophores on the back. 126. URINOPHILUS ERYTHRURUS Eigenmann Urinophilus erythrurus Eigenmann, 1922, Bijdr. Tot de Dierk. Amst., X XII, 114, pl. iv, figs. 10-16; Pearson, 1924, Ind. Univ. Studies, XI, no. 64, 17.
Eastern Peru and northern Bolivia 15584,10,120-145mm.,typeandparatypes,RioMorona,Allen,October,1920. 15604, , Rio Morona, Allen, October, 1920.
15715,3,64-74mm.,RioParanapura,Yurimaguas,Allen,November,1920. 15713,3,49-53mm.,Gosulimacocha,RioMorona,Allen,October,1920. 15714, 3, 45-51 mm., Rio Morona, Allen, October, 1920. 15717, 1, 127 mm., Rio Ucayali near Orellana, Allen, August, 1920. 17104,1,75mm.,Rurrenabaque,Bolivia,Pearson,November,1921. It is of interest and possibly significant that both Pearson’s specimen and those from Peru were all collected along the fringe of the piedmont, in the edge of the flood plains.
Body compressed; head depressed, flat below, arched above; depth of head equals distance between pupillary centers; eye about 5 in head; interorbital distance equal to snout; 5-9 teeth forming a crescentic row below the snout; a series of about four claw-like teeth on the mawxillaries, concealed in a fleshy pocket; very few recurved teeth at the ends of the mandible, whose extremities are widely separated; outer barbel extending to the end of the interopercular spines; the latter numerous (about ten), their tips curved; opercular spines more numerous (about twenty-five), also curved at the tip; pectorals about equal to the head less half the snout; distance between the origin of the ventrals and base of caudal equal to about one-third the length; origin of dorsal forward of the vertical from the origin of the anal; depth of caudal peduncle 3 or more in its length; caudal emarginate.
Plumbeous above; white below, middle of caudal dark, the outer parts pink inlife.
The maxillary is a two-part bone; the inner (mesial) division articulates in a
ANNOTATED LIST OF THE SPECIES 163 movable joint with the wings of the ethmoid and is free of teeth; the ectal moiety of the maxillary with several overlapping, claw-like teeth in a single series. The barbels are continuous with the end of the maxillary. A thin, blade-like bone covers the end of the maxillary, protecting the teeth; the inner, proximal end of this blade-like bone is narrowed and curved around the maxillary.
Genus 63: TRIDENS Eigenmann and Eigenmann Tridens Eigenmann and Eigenmann, 1889, Proc. Cal. Acad. Sci., (2), I, 53; Higenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sei., I, 339; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 400; Eigenmann,1918,Mem.CarnegieMus.,VII,369.
Type: Tridens melanops Eigenmann and Eigenmann The Brazilian-Peruvian frontiers Two species described from closely adjacent localities, and from few types, but so different as to suggest distinct genera.
Long body form, elongated anal (twenty or more rays), its origin before that of the dorsal; ventrals small and nearer the end of the snout than to the base of the caudal; head extremely depressed; eye lateral, extending upon both dorsal and ventral surfaces; labial teeth fine, followed by stronger teeth in the jaws; gill-membranes joined to form a broad, free fold across the isthmus; two maxillary barbels; opercle and interopercle spinous.
127. TRIDENS MELANOPS Eigenmann and Eigenmann TridensmelanopsEigenmannandEigenmann,1889,Proc.Cal.Acad.Sci.,(2),IT,53,I¢a; Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sei., I, 339; Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 400; Eigenmann, 1918, Mem. Carnegie Mus., VII, 369, pl. xl, figs. 1 and 2. The Amazon near the Peruvian-Brazilian frontier Known only from the types, the largest 27 mm. in length. Noteworthy for the three trident-shaped spines of the opercle, smaller preopercular spines of similar form and greatly reduced barbels; coterminous anal and dorsal fins, the rays of the former diminishing caudally; caudal fin rounded. Family VIII: Astroblepidae SiluroideiastroblepiformesBleeker,1863,Nederl.Tijdsch.Dierk.,I,110. Siluridae proteropodes (in part) Giinther, 1864, Cat. Fish. Brit. Mus., V, 4. ArgiudaeGill,1872,ArrangementofFamiliesofFishes,19; Eigenmann and Eigenmann, 1888, Amer. Nat., XXII, 647; Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 347. Argiinae Regan, 1904, Trans. Zool. Soc. London, XVII, 307; Regan, 1905, Ann. Mag. Nat. Hist, (7), XV, 529-534. Astroblepidae Eigenmann, 1922, Mem. Carnegie Mus., [X, 50.
164 FISHES OF WESTERN SOUTH AMERICA Naked catfishes with inferior mouth; lower lip much expanded and reverted; teeth bicuspid, in a narrow band in each jaw; gill-membranes broadly united with the isthmus; anterior and posterior nares closely approximated; maxillary barbels present, no mental or nasal barbels. Dorsal vertically placed above the ventrals; air bladder enclosed within Weberian apparatus forward, with a bony diaphragm. For reasons given below the genera Cycloptum, Arges, Brontes, and Styogenes, once considered members of a family Argiidae, are here synonyms of Astroblepus. Genus 64: ASTROBLEPUS Humboldt AstroblepusHumboldt,1806,Rec.d’Obs.Zool.Anat.,I,19; ‘igenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 417; Eigenmann,1922,Mem.CarnegieMus.,EX,51.
CyclopiumSwainson,1839,Nat.Hist.Fish.,IT,3065.
Arges Cuvier and Valenciennes, 1840, Hist. Nat. Poiss., XV, 333, pl. 444; Giinther, 1864, Cat. Fish. Brit. Mus., V, 222; Regan, 1904, Trans. Zool. Soc. London, XVII, 307.
Brontes Cuvier and Valenciennes, 1840, Hist. Nat. Poiss., XV, 341, pl. 445. Styogenes Giinther, 1864, Cat. Fish. Brit. Mus., V, 223, humboldtit. Type: Astroblepus grixalvii Humboldt The Andean highlands from Colombia to Peru Cabezon, colloquial name in allusion to large head.
Adipose fin short, near caudal, with a short spine; teeth small, the mandibulars and inner intermaxillaries broadened and notched at the tips; eyes small and upturned.
One of the most successfully formed of all groups of fishes for climbing; lips flattened and suctorial; paired fins set so as to inch forward or backward in opposition to swift currents; gills so adapted as to valve water inward at the tops of the gill opening and to exhale at the bottom while using the mouth as a holdfast. The Eigenmanns (1890) expressed doubt that the Humboldt genus A stroblepus should be placed with the genera Arges, Cyclopium, and Brontes in Gill’s family Argiidae, on account of the supposed lack of ventral fins. Meanwhile the many years’ collecting of the Carnegie Museum and Indiana University expeditions have brought to light no specimens without ventrals. This seems to justify (Higenmann, 1922 b) relegating the above genera to the synonomy of Astroblepus Humboldt. 128. ASTROBLEPUS SABALO (Cuvier and Valenciennes) ArgessabaloCuvierandValenciennes,1840,Hist.Nat.Poiss.,XV,335,pl.444,SantaAna; Giinther, 1864, Cat. Fish. Brit. Mus., V, 222; Steindachner, 1875, Sitzb. Kix. Akad. Wiss. Wien, LX. XII, 48, Tulumayo; Steindachner, 1876, Sitzb. IKXI<. Akad. Wiss. Wien, LX XII, 598; Cope, 1878, Proc. Amer. Phil. Soe., XVII, 681, seven, R. Urubamba; Steindachner, 1879, Denkseh. Kix. Akad. Wiss. Wien, XLI, 23; Steindachner, 1882 (1883), Denksch. KIX. Akad. Wiss. Wien, IV, 17, pl. iv, fig. 2 and 2b, Rio Huambo;