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References should be typed in the following form: 943 Croat, T. B. 1978. Flora of Barro Colorado Island. Stanford University Press, Stanford, Calif., pp. 1963. A of montane and lowland rain forest in Ecuador. Grubb, P. J., J. R. Lloyd, and T. D. Pennington. comparison floristics. Journal of 51: 567-601. I. The forest structure, physiognomy, and Ecology, in 63-80. In Browman, D. L.,and R. A. Langdon, E. J. M. 1979. Yage among the Siona: Cultural patterns visions, pp. Stars. Mouton The Netherlands. Schwarz, eds., Spirits, Shamans, and Publishers, Hague, 785-821. In J. H., ed., Handbook of South American Murra, J. 1946. The historic tribes of Ecuador, pp. Steward, of American Smithsonian Indians. Vol. 2, The Andean Civilizations. Bulletin 143, Bureau Ethnology, Institution, Washington, D.C. Fieldiana: n.s., 6: 1-522. Stolze, R. G. 1981. Ferns and fern allies of Guatemala. Part II. Polypodiaceae. Botany, as must be by Illustrations: Illustrations are referred to as "figures" in the text (not "plates"). Figures accompanied such as "x are not some indication of scale, normally a reference bar. Statements in figure captions alone, 0.8," acceptable. and See recent issues of Fieldiana for details of style. Captions should be typed double-spaced consecutively. and All illustrations should be marked on the reverse with author's name, figure number(s), "top." x be 8Vi x 11 inches x 28 cm), and may not exceed UV6 16V* Figures as submitted should, whenever practicable, (22 This on boards in the to be obtained in the printed work. inches (30 x 42 cm). Illustrations should be mounted arrangement for transmission to the as follows: Pen and ink drawings maybe originals (preferred) original set should be suitable printer be but within the size limitation; and must be high-quality, glossy, or photostats; shaded drawings must originals, photostats unless otherwise illustrations will be returned to the author publication black-and-white prints. Original corresponding upon specified. or color must make prior Authors who wish to publish figures that require costly special paper reproduction arrangements with the Scientific Editor. The author will normally receive a copy Page Proofs: Fieldiana employs a two-step correction system. corresponding can be made and answered. Only one set of of the edited manuscript on which deletions, additions, and changes queries of must be made on the set of proofs. Changes in page page proofs will be sent. All desired corrections type single page if the are in can only be made proofs (as opposed to corrections) very expensive. Author-generated changes page proofs author agrees in advance to pay for them.

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Zoology NEW SERIES, NO. 61

Hoplomyzon sexpapilostoma, a New Species of Venezuelan (Pisces: ), with Comments on the Hoplomyzontini

Donald C. Taphorn Crispulo Marrero Museo de Ciencias Naturales de Guanare Universidad National Experimental de los LLanos Occidentales Ezequiel Zamora, Programa de Recursos Naturales Renovables Guanare, Portuguesa Venezuela 3310

Accepted October 17, 1989 Published November 30, 1990 Publication 1417

PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY © 1 990 Field Museum of Natural History ISSN 0015-0754 PRINTED IN THE UNITED STATES OF AMERICA Table of Contents List of Tables

Abstract 1 1 . Comparison of mensural characters for

Resumen 1 type specimens of Hoplomyzon and para-

Introduction 1 types of H. sexpapilostoma 2 Methods 2 2. Character comparison of the tribes Hoplo- Hoplomyzon Myers, 1 942 2 myzontini and Bunocephalini 9 Key to Species of Hoplomyzon Myers .... 3

Hoplomyzon sexpapilostoma, new species . . 4 Status of the Hoplomyzontini 8 Acknowledgments 9 Literature Cited 9

List of Illustrations

1 . Color patterns, caudal fin blotch, and ventral view of anterior of Hoplomyzon sexpapilostoma 3 2. Views ofpectoral and pelvic girdles ofHop- lomyzon sexpapilostoma, Ernstichthys anduzei, Bunocephalus amaurus, and Xi- liphius cf. lepturus 4 3. Ventral elements of Hoplomyzon sexpa- pilostoma and Ernstichthys anduzei 6 4. Caudal vertebrae and caudal skeletons of Hoplomyzon sexpapilostoma, Bunocepha- lus amaurus, and Xiliphius cf. lepturus ... 7

in

Hoplomyzon sexpapilostoma, a New Species of Venezuelan Catfish (Pisces: Aspredinidae), with Comments on the Hoplomyzontini

Abstract Apure (Cuenca Rio Orinoco) de Venezuela occi- dental. Se distingue de las otras especies del genero A new species of aspredinid catfish belonging to (H. atrizona y H. papillatus), porque tiene la sig- the tribe Hoplomyzontini was collected as part of uiente combination de caracteres: ( 1 ) El borde an- a general inventory ofthe fishes ofthe Apure River terior del hocico es ligeramente bilobulado (vs. Drainage (Orinoco Basin) of western Venezuela. visiblemente bilobulado en H. papillatus y recto Hoplomyzon sexpapilostoma, new species, is dis- en H. atrizona). (2) No posee barbillas en el rictus tinguished from all known aspredinids by the fol- como H. atrizona. (3) Posee cuatro papilas en el labio lowing combination ofcharacters: ( 1 ) The anterior superior, a diferencia de H. papillatus que border ofthe snout is slightly emarginate, vs. deep- posee tres (o cinco si incluimos el par rictal). (4) ly emarginate in H. papillatus or straight in H. Radios dorsales i5 (vs. i6 en H. atrizona e i3i en atrizona. (2) There are no barbels at the rictus of H. papillatus). (5) Las barbillas maxilares son lar- the mouth as in H. atrizona. (3) They have four gas pero no sobrepasan el punto de nacimiento de papillae on the upper lip, instead of three as in H. la aleta pectoral (18.8% de el largo estandar). (6) papillatus (or five, including the rictal pair). (4) Los escudos de la linea lateral describen un zigzag Dorsal rays i5 vs. i6 in H. atrizona, i3i in H. papil- moderado hasta un punto ubicado aproximada- latus. (5) Maxillary barbels long but not surpassing mente en la mitad de la aleta dorsal, pero de ahi the pectoral fin origins (18.8% SL). (6) The ossified en adelante forman una linea recta hasta el pe- lateral line tubules are arranged in a zigzag pattern dunculo caudal (en H. papillatus se presentan en to a point beneath the center of the dorsal fin base, zigzag a lo largo de toda la linea lateral, y en H. but are straight from there back to the caudal pe- atrizona forman una linea recta sobre toda la linea duncle (in H. papillatus the zigzag pattern contin- lateral). (7) El segundo radio de la aleta pelvica es ues to the caudal peduncle, and in H. atrizona it ligeramente mayor que los restantes (forma un fi- is completely straight). (7) The second pelvic ray lamento en H. papillatus y es corto en H. atrizona). is slightly longer than the rest (it forms a filament (8) Las aletas dorsal y anal, estan unidas a la linea in H. papillatus and is short in H. atrizona). (8) media del cuerpo mediante unas membranas (es- The dorsal and anal fins are united to the dorsal tan unidas en H. papillatus y no unidas en H. midline of the body by membranes (united in H. atrizona). Hoplomyzon esta redefinido para incluir papillatus, free in H. atrizona). Hoplomyzon is la especie nueva. redefined to include the new species.

Introduction Resumen Since 1978, one of us (D.C.T.) has made col- Una especie nueva de bagre aspredinido de la lections of fishes in the Apure River drainage of tribu Hoplomyzontini, Hoplomyzon sexpapilos- western Venezuela as part of a general inventory toma, especie nueva, fue colectado durante un in- of the ichthyofauna. While working up the aspre- ventario general de los peces de la cuenca del Rio dinid material, we identified two new records for

TAPHORN & MARRERO: HOPLOMYZON SEXPAPILOSTOMA Table 1. Comparison of mensural characters for the type specimens of the three species of Hoplomyzon and ten paratypes of H. sexpapilostoma (as thousandths of SL). Fig. 1. Hoplomyzon sexpapilostoma. A, Most common color pattern (holotype). B, Color pattern of large adults, in this case a male (mcng 18741). C, Caudal fin blotch, lateral view (holotype). D, Ventral view of the anterior part of Hoplomyzon sexpapilostoma (holotype). Scale bars are 2 mm.

Diagnosis— (Stewart, 1 985, modified to include for a total of five; rictal barbels lacking; os- new species.) Distinguished from all known as- sified lateral-line tubules arranged in a zigzag predinids by having four or five stout, fleshy pa- pattern from near opercle to base of caudal pillae on upper lip. Differs further from other gen- fin . . . Hoplomyzon papillatus Stewart, 1985 era of Hoplomyzontini in having 9 or 1 1 pre-anal 1 b. Dorsal rays i5 or i6; upper lip with four stout, fin plates, with three or four "paired elements"; fleshy papillae plus either a slender barbel or the pectoral spine length (excluding flexible tip) a stout fleshy papilla at each rictus for a total less than 25% standard length; and relatively short of six; ossified lateral-line tubules arranged in posterior cleithral and coracoid processes; resem- a straight line or zigzag to beneath dorsal fin bles Dupouyichthys, but differs from Ernstichthys and then continuing posteriorly in a straight in having relatively deeper caudal peduncle, great- line 2 er width between anterior nostrils, and wider in- 2a. Each rictus with a slender barbel; dorsal rays terorbital (table 1). i6; ossified lateral line tubules arranged in straight line Hoplomyzon atrizona Schultz, 1 944 Key to Species of Hoplomyzon Myers 2b. Each rictus with a stout fleshy papilla; dorsal rays i5; ossified lateral-line tubules arranged la. Dorsal rays i3i; upper lip with three stout, in a zigzag to beneath dorsal fin

fleshy papillae plus one at each rictus of mouth . . Hoplomyzon sexpapilostoma, new species

TAPHORN & MARRERO: HOPLOMYZON SEXPAPILOSTOMA Fig. 2. A, B, Hoplomyzon sexpapilostoma (mcng 5376). C, D, Ernstichthys anduzei (mcng 1 3845). E, F, Bunoceph- alus amaurus (mcng 6038). G, H, Xiliphius cf. lepturus (mcng 5547). A, C, E, and G show ventral views of the pectoral and pelvic girdles (with elements of right pectoral fin omitted). B, D, F, and H show dorsal views of pectoral = = = girdle and left cleithral process. Scale bars are 2 mm. abf abductor fossa; bpt basipterygium; cl cleithrum; co = = = coracoid; pc posterior cleithral process; pfr pectoral fin radials (after Schaefer, 1987).

Hoplomyzon sexpapilostoma, new species, Figures 1983457.4231 (5); all taken with holotype. Unless in- 1-4. dicated otherwise, following lots are all from Venezuela, Portuguesa state (field numbers follow dates): mcng 38 1 (6), Guanare River in La Raya, about 28 km N of Gua- Holotype— mcng 22.70 standard 18669, mm nare, 6 June 1979, DCT79-70, D. Taphorn, C. Lilyes- length, Venezuela, Barinas State, Apure River trom. mcng 382(12), Tucupido River about 2 km south Drainage, Rio Masparro at site of Masparro Dam, of Highway 5 bridge, 27 Feb. 1979, DCT79-30, D. Ta- phorn, C. Lilyestrom, E. Salas, R. Feo, G. Feo. mcng 70°06'00"W, 8°50'40"N, bottom rock rubble, gravel 5480 (4), border of Barinas and Portuguesa states, Bo- and sand with large exposed boulders. While we cono River about 1 km below dam site, 5 Nov. 1982, were fishing, the river was diverted through tun- DCT82-72, D. Taphorn, C. Lilyestrom, C. Olds, S. Reid, nels to expose the dam site and the reach was J. Reid, M., L. and W. Lilyestrom. mcng 6439 (2), state of Frio or Torbes about 35 km southeast rapidly drying up. Specimens were collected with Tachira, River, of San Cristobal, 27 May 1982, DCT82-46, D. Taphorn, hand nets from the remaining puddles between C. Lilyestrom, C. Olds, mcng 8530 (4), Tucupido River 1430 and 1645 D. and C. by Taphorn Lilyestrom, at dam site, 15 Jan. 1981, DCT81-1, D. Taphorn, C. 13 November 1983. Lilyestrom, A. Fernandez, mcng 8968 (1), Tucupido River near town of Tucupido, 16 Jul. 1980, DCT80-73, Paratypes— mcng 5376 (70 specimens); mzusp 38894 D. Taphorn, C. Lilyestrom, L. Nico. mcng 9805 (5), (5); fmnh 97762 (5); mbucv 17791 (7); and nrm A88/ creek at bridge 30 km north of Guanare on road to

FIELDIANA: ZOOLOGY Fig. 2. Continued.

3 1 Biscucuy, May 1980, DCT80-66, D. Taphom, S. Reid, border of snout but slightly emarginate (figs. 1 a, C. Staver, J. Karr. mcng 11825 Moroturo River (1), b, d) vs. deeply emarginate in H. papillatus or about 1 5 km north of Aparicion, 1 2 Aug. 1 983, DCT83- nearly straight in H. atrizona. (2) No barbels at 28, D. Taphorn, C. Lilyestrom, E. Sutton, J. Sanchez. rictus of mouth as in H. atrizona Four mcng 15507 (2), Guanare River at Guanare just below (fig. Id). (3) dam for irrigation system, 1 7 Jan. 1 984, KW84-2, K. papillae on upper lip (fig. Id) instead of three as Winemiller. 18741 near mcng (2), Saguas River, bridge, in H. papillatus. (4) Dorsal rays i5 vs. i6 in H. in park on road to Chabasquen, 1 May 1988, ASF88-2, atrizona and i3i in H. papillatus. (5) Maxillary A. Flecker, mcng 18905 (2), Guache River, 2 May 1988, barbels long but not surpassing pectoral origins ASF88-3, A. Flecker, mcng 18906 (7), Barinas, Yuca River, 3 May 1988, ASF88-4, A. Flecker, mcng 19279 (18.8% SL). (6) Ossified lateral-line tubules ar- (1), Bocono River below dam, 1 1 Jul. 1988, MC88-1, ranged in zigzag pattern to point beneath the center A. Barbarino. mcng 19780 Rio Las Marias about 5 (4) of dorsal fin base, but straight from there back to km NW of El Potrero, 1 8 Dec. 1 988, ASF88-9, A. Beck- caudal peduncle (in H. papillatus the zigzag pattern er, B. Feifarek, C. Marrero, N. Camargo, M. Jimenez. continues to caudal peduncle, in H. atrizona the Diagnosis— Hoplomyzon sexpapilostoma is line is completely straight). (7) Second pelvic ray distinguished from all known aspredinids by the slightly longer than other pelvic rays (it forms a following combination of characters: (1) Anterior filament in H. papillatus and is short in H. atri-

TAPHORN & MARRERO: HOPLOMYZON SEXPAPILOSTOMA Fig. 3. Ventral elements of cleared and stained specimens. A, A 17.9 mm SL of Hoplomyzon sexpapilostoma (mcng 5376). B, A 26.2 mm SL of Hoplomyzon sexpapilostoma (mcng 5376). C, Ernstichthys anduzei (mcng 1 3845). The black dots represent the anus. Scale bars are 2 mm.

zona). (8) Dorsal and anal fins united to dorsal Pigmentation— Three dark conspicuous cross- midline of body by membranes (united in H. pa- bands on dorsum— first begins at point near dorsal pillatus, free in H. atrizona). origin and other two cross body between the dorsal

Description— Mensural characters are present- fin and tail (fig. la); caudal fin with dark blotch at ed in Table 1 for comparison with other species base that covers bases of upper eight rays but does

of Hoplomyzon. Anterior nostril on short tube, not extend onto bottom ray (fig. lc). Females (and situated just behind anterior margin of snout and probably immatures ofboth sexes) with thin, black,

directed anteriorly (figs, la, b). Posterior nostril masklike band that passes vertically through eyes

not very close to eye, about equidistant from an- (fig. la). Band is wider in some adults and whole

terior nostril and the eye, with lunate opening much anterior portion of head dark (fig. lb). Pectoral smaller than eye diameter. Maxillary barbel sup- spine with small black central blotch, extending ported by a bony element that extends for about onto membrane that unites spine with first

one fourth of its length. Posterior coracoid pro- branched ray (fig. la); spot larger and darker in

cesses extend far back and form lyre within which males (fig. 1 b). Areas between dark bands on body, anterolateral processes of pelvic bone are included anterior band through eyes, and maxillary barbels

(fig. 2a). Lower caudal fin lobe longer than upper light tan. Area posterior to mask, and dorsum to

(fig. lc). just anterior to first dark band across body brown. Meristic Data— Dorsal fin i5; pectoral I5i; pec- Venter beige except where dark lateral bands con- toral spine with 4—5 teeth on posterior margin, tinue ventrally.

anterior margin smooth (fig. 2a); flexible part of Distribution— So far found only in the Apure pectoral spine 3 1 .7% of its total length; pelvies i4i, River drainage in Andean rivers and streams at none ofrays filamentous; anal fin ii5 or iii5; caudal altitudes from about 90 to 600 m. They have been i7i, with five rays attached to upper hypural and found living sympatrically with Ernstichthys an- four to lower (this characteristic apparently unique duzei at the localities given by Stewart (1985). to the Hoplomyzontini among all known catfish- Comments—Hoplomyzon sexpapilostoma is in-

branch 1 for es); iostegal rays four; dorsal plates 2 ; pre- termediate between the two described species

anal plates nine (figs. 3a, b); ventral plates 14; some characters; however, its several unique char-

ossified lateral-line tubules 4 1 . acters, and the morphometric and meristic difler-

FIELDIANA: ZOOLOGY A B

Fig. 4. Caudal vertebra in lateral (a) and frontal (b) views, and caudal skeletons. A, D, Hoplomyzon sexpapilostoma = (mcng 5376). B, E, Bunocephalus amaurus (mcng 6038). C, F, Xiliphius cf. lepturus (mcng 5547). Ct centrum, He = = hemal canals, HY = hypurals, Nc = neural canals, PH posterohyal. Scale bars are 2 mm.

ences, justify species status. We believe that the Opposing plates are separate from each other in character given as typical for the Hoplomy- front of and next to the dorsal and anal fin bases, zon by Stewart (1985), 1 1 preanal plates with only but fuse on the dorsal and ventral midlines behind four paired elements, should be modified to 9 or the dorsal and anal fin bases, respectively. The 1 1 preanal plates to include Hoplomyzon sexpa- pairs are larger and closer to each other behind the pilostoma. dorsal and anal fin bases. The attachment of bifid Comparison of the osteology of Hoplomyzon neural spines to dermal plates in the loricariid sexpapilostoma with that of other aspredinids has Hypostomus plecostomus described by Schaefer revealed several important features. The so-called ( 1 987) is similar to the condition observed in Hop- dermal plates along the dorsum and venter, and lomyzon sexpapilostoma. However, H. plecosto- the "paired elements" of the belly (figs. 3a, b), are mus lacks bifid hemal spines, and the single hemal actually the expanded, flattened tips of bony struts spines are expanded on the posterior vertebrae, (probably modified neural and hemal spines) that not unlike the condition observed in Bunocephalus extend from the highly compressed vertebrae to and Xiliphius. the skin. They extend both dorsally and ventrally In Hoplomyzon sexpapilostoma (figs. 2a, b) and

to join the vertebrae to the external plates and Ernstichthys anduzei (figs. 2c, d) the pelvic girdle

form a sort of X-shaped girder (fig. 4a) with two and fins are situated between the elongated pos- centers (the neural and hemal canals). We have teriorly projecting processes of the pectoral girdle found these girders in Hoplomyzon sexpapilosto- (inside the "lyre"). This contrasts greatly with the

ma and Ernstichthys anduzei but they are absent condition observed in Bunocephalus amaurus (figs.

in Bunocephalus amaurus (fig. 4b) and Xiliphius 2e, f) and Xiliphius cf. lepturus (figs. 2g, h), in which

cf. lepturus (fig. 4c). the pelvic girdle is situated much farther posteri- Thus the vertebrae and struts form a solid bony orly. connection from the top to bottom of the fish. The greatly reduced number of caudal rays i7i,

TAPHORN & MARRERO: HOPLOMYZON SEXPAPILOSTOMA with five attached to the dorsal hypural plate (fig. capture and introduce fine particulate organic mat- 4d), is unique among known (Lundberg ter into the riverine foodweb. = & Baskin, 1969). Bunocephalus and Xiliphius have Etymology— From the Latin sex six and pa- = = i8i with five on each hypural (figs. 4e, f). pilo papilla (tubercle), the Greek stoma mouth. Ecology—Hoplomyzon sexpapilostoma typi- The name refers to the presence of six buccal pa- cally inhabit small Andean rivers or creeks with pillae (four on upper lip, one at each corner of a gravel to boulder substrate and moderate to high mouth) that distinguish the species from its con- current. Water temperatures are usually between geners. 24 and 28° C. Water is typically clear and flow is greatly reduced during the dry season (November- May), but flow is violent and turbidity high during the rainy season. Status of the Hoplomyzontini We speculate that their peculiar skeletal struc- tures are an adaptation to living in the interstices In the description of Ernstichthys anduzei, Fer- of a constantly shifting substrate of gravel. These nandez Y. (1953) recognized two families in the fish may have evolved structural struts that serve order Asprediformes: the Aspredidae (to include to protect them from being crushed when trapped Aspredo and other long anal fin-based aspredin- inside an "avalanche" of small stones. Among the ids), and the Bunocephalidae (for most other gen- aspredinids we have examined, we have found this era) and proposed the division of the Bunoce- condition only in the Hoplomyzontini, all ofwhich phalidae into two subfamilies: Bunocephalinae for live in similar habitats. In contrast, Xiliphius live Bunocephalus, Xiliphius, Agmus, etc. and Hop- buried in the bottoms of larger rivers in sand or lomizontinae for Hoplomyzon, Dupouyichthys, mud substrates. Bunocephalus are usually taken and Ernstichthys. As presently defined, the clas- from among leaf litter in small forest streams. sification ofthese fishes is essentially the same, but This new species and all other members of the Asprediformes is not used, and each subordinate Hoplomyzontini are cryptically colored, with al- level has been "demoted" one notch so that the ternating light and dark disruptive bands. This family Aspredinidae comprises the subfamilies distinct, alternating pattern is not known among Aspredininae (e.g., Aspredo) and Bunocephalinae, other aspredinids, though all are cryptically col- with the latter subdivided into the tribes Buno- ored to some degree. cephalini (Bunocephalus, Xiliphius, etc.) and Hop- Nothing is known about the reproduction ofthis lomyzontini (Hoplomyzon, Ernstichthys, and Du- species, although the females of the type series pouyichthys) as defined by Myers (1942) and were ripe with relatively large, yellowish eggs in Stewart (1985). Both Fernandez Y. (1953) and November (beginning of the dry season). The ob- Stewart (1985) considered the "superficial" bony served sexual dimorphism (mature males were plates as unique derived features that provide ev- consistently larger and had a different color pat- idence for the monophyletic status of the Hoplo- tern) suggests that some sort of courtship might myzontini. Our observations on structure of the be expected. vertebrae, position of the pelvic girdle, the unique Although H. sexpapilostoma is small in size, and reduction of caudal elements, and banded pig- a seemingly insignificant species, it may play an mentation (table 2) are further evidence for mono- important role in the trophic continuum of trop- phyly of the Hoplomyzontini and widen the mor- ical Andean rivers. The collection ofsome 70 spec- phological gap that separates these tiny catfishes imens when a section of the Masparro River was from other aspredinids. Further osteological anal- dried indicates that they are present in fairly high yses will probably reveal that the currently rec- density, and that their rarity in collections is due ognized genera should be regrouped into subfam- to the usually inaccessible habitat that they occupy ilies distinct from those currently recognized. (we were able to collect hundreds of Xiliphius cf. Because we lack comparative material on Aspre- lepturus under similar circumstances when a dam dininae at this time, we cannot resolve phyloge- was closed on the neighboring Bocono River). netic relationships. However, based on our find- Stomach content analyses revealed a diet of ben- ings noted above, and the overall morphological thic macroinvertebrates, mainly aquatic insect lar- similarity apparent in the few illustrations of As- vae (Ephemeroptera). These insects probably shred predininae available, we suggest as a working hy- leaves (Vannote et al., 1 980) as a food source. Thus pothesis of relationship that the Aspredininae will this catfish is a predator on the organisms that prove to be more closely related to the Buno-

FIELDIANA: ZOOLOGY Table 2. Character comparison of the tribes Hoplo- Donald Stewart, Mr. Leo Nico, and one anony- and myzontini Bunocephalini. mous reviewer reviewed the manuscript and pro- vided many useful suggestions. The Research Of- 1 1 o In m n t i n i — p y/o Hoplo- fice of unellez and FUNDACiTE provided funds for myzon, Ernstichthys, and the Apure River Ichthyological Inventory. Cris- Dupouyichthys (not yet Bll 11 hi epha I i ii i Huno- the illustrations. seen) cephalus and Xiliphius pulo Marrero drew

1) Caudal vertebrae in Vertebrae in form of a form of an "X." cross. 2) Pelvic girdle anterior; Pelvic girdle posterior; anterior extensions of anterior extensions of Literature Cited the pelvic bone includ- the pelvic not included ed inside arch formed in arch formed by pos- Fernandez Yepez, A. 1953. Algunas notas sobre los by posterior coracoid terior coracoid process- peces Asprediformes con description de Ernstichthys processes. es. anduzei, nuevo e interesante Bunocephalido. Nove- 3) Preanal plates present. No preanal plates. dades Cientificas, Ser. Zool., Museo de Historia Nat- 4) Principal caudal rays Principal caudal rays ural La Salle, 11: 1-7. 5+4. 5 + 5. Lundberg, J., and J. Baskin. 1969. The caudal skel- uniform or 5) Pigmentation pattern Pigmentation eton of the catfishes, order Siluriformes. American not banded. of alternating light and mottled, Museum Novitates, 2398: 3-49. dark bands. Myers, G. 1942. Studies on South American fresh- 6) Dorsum and venter No dermal plates. water fishes. I. Stanford Ichthyological Bulletin, 2(4): with series of paired 89-1 14. dermal plates. Schaefer, S. 1987. Osteology of Hypostomus plecos- tomus (Linnaeus), with a phylogenetic analysis of the loricariid subfamilies (Pisces: Siluroidei). Contribu- tions in Natural of Los An- cephalini, sharing the characters of a posterior Science, History Museum geles County, 394: 1-31. pelvic girdle placement and a nonbanded color Stewart, D. 1985. A review of the South American pattern (although these characters may prove to catfish tribe Hoplomyzontini (Pisces, Aspredinidae), be once the character states have plesiomorphous with descriptions of new species from Ecuador. Fieldi- been polarized with outgroup comparisons), as well ana: Zoology (New Series), 25: 1-19. as the relatively simple cross-shaped vertebrae that Vannote, R., G. Minshall, K. Cummins, J. Sedell, lack the dorsal and ventral extensions. and C. CusHrNG. 1 980. The river continuum con- cept. Canadian Journal of Fisheries and Aquatic Sci- ences, 37: 130-137.

Acknowledgments

We thank the many collectors listed above who helped collect the types. Drs. John Lundberg and

TAPHORN & MARRERO: HOPLOMYZON SEXPAPILOSTOMA

Field Museum of Natural History Roosevelt Road at Lake Shore Drive Chicago, Illinois 60605-2496 Telephone: (312)922-9410