Tympanopleura piperata Eigenmann, 1912

Walsh, Stephen J., Ribeiro, Frank Raynner Vasconcelos & Py-Daniel, Lúcia Helena Rapp, 2015, Revision of Tympanopleura Eigenmann (Siluriformes: Auchenipteridae) with description of two new species, Neotropical Ichthyology (Neotrop. Ichthyol.) 13 (1), pp. 1-46 : 33-42

Tympanopleura piperata Eigenmann, 1912 Figs. 1e , 5 , 6f , 16 , 17

Tympanopleura piperata Eigenmann, 1912: 203-204 , pl. 20 [type-locality: - British Guiana (= Guyana), Essequibo River at Crab Falls]. - Henn, 1928: 75 [holotype listed]. -Eigenmann & Myers, in Myers, 1928: 85 [comments on size and comparison with T. alta ]. -Eigenmann & Allen, 1942: 138 [designated type-species of genus]. - Gosline, 1945: 25 [citation]. - Fowler, 1951: 456 [cited as generic type (orthotype)]. -Ibarra & Stewart, 1987: 84,86 [holotype and paratype listed]. - Burgess, 1989: 286 [checklist]. - Hardman et al., 2002: 235 [checklist; Essequibo and lower Potaro rivers, Guyana]. - Ferraris, 2003: 471 [checklist; as synonym of Ageneiosus piperatus ; type-locality; holotype; distribution after Walsh, 1990]. - Ferraris, 2007: 70 [type checklist; as synonym of Ageneiosus piperatus ; information duplicated from Ferraris, 2003].

Ageneiosus piperatus . -Rosa & Menezes, 1996: 657 [in checklist of species of conservation concern, status undetermined]. - Ferraris, 2003: 472 [checklist; see above]. - Watkins et al., 2004: 50 [in list of species from Iwokrama Forest, Guyana; Essequibo and Burro-Burro rivers; identification not verified]. - Mojica et al., 2005: 204 [checklist; Colombian Amazon; ICNMHN cataloged lot (5702); identification not verified]. -Bogotá-Gregory & Maldonado-Ocampo, 2006: 82 [checklist; Colombian Amazon, after Mojica et al., 2005]. -Akama & Sarmento-Soares, 2007: 116 [checklist; type-locality; distribution]. - Ferraris, 2007: 70 [type checklist; see above]. -Maldonado-Ocampo et al., 2008: 208 [checklist; Colombian Amazon, after Mojica et al., 2005, Bogotá-Gregory & Maldonado-Ocampo, 2006; identification(s) not verified]. -Vari et al., 2009: 44 [checklist; Roraima, Brazil]. -Ribeiro & Rapp Py-Daniel, 2010: 99, 103 [in diagnosis of Ageneiosus uranophthalmus and material examined]. -de Souza et al., 2012: 36 [checklist; Rupununi River, Guyana].

Diagnosis. Tympanopleura piperata is distinguished from congeners by its diminutive size (maximum size less than 50 mm SL vs. greater than 75 mm SL in all other species), a large cordiform gas bladder lacking posterior diverticula and with the tunica externa and internal longitudinal septum partially ossified in adults, and unique pigmentation on the caudal fin consisting of a dense patch of melanophores forming an hourglass-shaped band at its base (most visible in live or freshly preserved specimens). Tympanopleura piperata is further distinguished from T. atronasus in having a greater number of anal-fin rays (31-38 vs. 23-30), greater number of gill rakers on the first arch (16-23, mode 19 vs. 14-23, mode 16), fewer preanal vertebrae (14-16, mode 15 vs. 16-19, mode 17), fewer total vertebrae (39-41, mode 40 vs. 39-43, mode 41), fewer pleural rib pairs (4-5 vs. 7-8), shorter prepelvic length (41.3-47.0% SL vs. 49.2- 55.2% SL), greater distance from pelvic- to adipose-fin origin (36.7-50.0% SL vs. 31.2-38.1% SL), longer anal-fin base (30.9-39.3% SL vs. 22.1-27.6% SL), and absence of a dense patch of pigmentation on the flank above the anal-fin base and elongate streak of pigment in each caudal-fin lobe that is characteristic of T. atronasus . Tympanopleura piperata further differs from T. brevis in having fewer pectoral-fin rays (6-10, mode 9 vs. 10-12, mode 11), fewer gill rakers on the first arch (16-23, mode 19 vs. 20-24, mode 23), shorter predorsal length (28.8-34.4% SL vs. 35.1-44.0% SL), shorter prepelvic length (41.3-47.0% SL vs. 47.4-53.9% SL), shorter prepectoral length (23.6-28.3% SL vs. 27.9- 35.6% SL), shorter distance from pectoral- to dorsal-fin origin (15.2-20.9% SL vs. 21.4-27.0% SL), narrower body width at pectoral-fin origin (16.8-20.0% SL vs. 20.5-26.6% SL), shorter pectoral-fin spine (13.9-18.1% SL vs. 19.1-24.4% SL), shorter head length (22.2-27.8% SL vs. 29.7-35.6% SL), and a larger eye diameter (24.3-35.7% HL vs. 13.8-21.0% HL). Tympanopleura piperata differs from T. cryptica in having more anal-fin rays (31-38 vs. 23-30), fewer gill rakers on the first arch (16-23, mode 19 vs. 21-26, mode 22), greater number of total vertebrae (39-41, mode 40 vs. 38-41, mode 38), shorter preanal length (52.5-59.7% SL vs. 59.6-66.0% SL), shorter prepectoral length (23.6-28.3% SL vs. 29.7-33.8% SL), shorter distance from pectoral- to dorsal-fin origin (15.2-20.9% SL vs. 21.6-24.3% SL), longer anal-fin base (30.9-39.3% SL vs. 24.4-30.3% SL), and a slightly larger eye diameter (24.3-35.7% HL vs. 16.7-25.6% HL). Tympanopleura piperata differs from T. longipinna in having a slightly shorter anal fin (anal-fin rays 31-38, mode 35 vs. 34-42, mode 37), fewer pectoral-fin rays (6-10, mode 9 vs. 10-13, mode 11), fewer total vertebrae (39-41, mode 40 vs. 40-43, mode 43), narrower body width at pectoral-fin origin (16.8-20.0% SL vs. 21.1-25.7% SL), slightly shorter snout (31.4-43.6% HL vs. 40.3-57.1% HL) and narrower gape (34.8-53.6% HL vs. 51.3-65.3% HL), and a larger eye (24.3-35.7% HL vs. 11.6-18.5% HL). Tympanopleura piperata differs from T. rondoni in having a slightly longer anal fin (anal-fin rays 31-38, mode 35 vs. 28-37, mode 31), fewer pectoral-fin rays (6-10, mode 9 vs. 10-13, mode 11), fewer gill rakers (16-23 vs. 24-33), fewer pleural rib pairs (4-5, mode 4 vs. 4-6, mode 6), shorter predorsal length (28.8- 34.4% SL vs. 35.2-47.4% SL), shorter prepectoral length (23.6-28.3% SL vs. 29.2-39.0% SL), shorter distance from pectoral- to dorsal-fin origin (15.2-20.9% SL vs. 19.8-29.0% SL), greater distance from pelvic- to adipose-fin origin (36.7-50.0% SL vs. 24.0-41.5% SL), greater distance from dorsal- to adipose-fin origin (45.9-55.4% SL vs. 38.1-46.8% SL), narrower body width at pectoral-fin origin (16.8-20.0% SL vs. 21.8-29.5% SL), shorter pectoral-fin spine (13.9-18.1% SL vs. 17.1-21.0% SL), longer anal-fin base (30.9-39.3% SL vs. 23.1-32.5% SL), shorter head (22.2-27.8% SL vs. 26.5- 39.0% SL), slightly shorter snout (31.4-43.6% HL vs. 41.7- 53.6% HL) and narrower gape (34.8-53.6% HL vs. 51.0- 65.6% HL), larger eye (24.3-35.7% HL vs. 8.4-17.0% HL). Additionally, unlike T. piperata , T. rondoni has a heavily spotted pigmentation pattern and an elongated gas bladder with a pair of long, recurved diverticula.

Description. Morphometric data are summarized in Table 12. Tympanopleura piperata is the smallest species of the genus. Size range 23.0- 47.5 mm SL (n=80) for immature specimens, females, and non-nuptial males. Size range 38.5-46.9 mm SL (n=11) for pre-nuptial males. No peak nuptial males were examined. Dorsal profile of head and nape gently sloping upward, nearly straight or slightly concave from tip of snout to base of dorsal-fin spine. Head depressed but not greatly flattened; head relatively deep at midpoint of supraoccipital, 54.3-69.7% HL. Dorsal profile of body posterior to dorsal fin slightly convex to base of upper caudal-fin lobe. Caudal peduncle moderately deep, 7.6-10.5% SL. Body widest at origin of pectoral fin, gradually tapering in width to base of caudal fin.

Head length 22.2-27.8% SL. Mouth subterminal, upper jaw extended only slightly anterior to tip of lower jaw. Snout moderately short, 31.4-43.6% HL. Anterior margin of upper jaw weakly rounded to squared off in dorsal profile. Premaxillary and dentary tooth bands narrow, teeth small, conical. Premaxillary teeth in a series of about 2-4 irregular rows at midline, tapered to 1-2 rows on lateral edges, posteriormost area of premaxilla devoid of teeth. Dentary tooth patch in an irregular series of about 3-4 rows. Eye large, 24.3-35.7% HL, nearly equally visible from dorsal and ventral profile, covered by thin layer of epidermis ( Fig. 1e ). Posterior edge of lower jaw approximately below middle of eye. Fontanelle groove relatively short, extending from posterior margin of mesethmoid to a point anterior to the plane passing through the rear margins of the orbits. Anterior nares just lateral to tips of mesethmoid wings; posterior nares offset from central margin of mesethmoid. Gill membranes broadly fused to isthmus at anterolateral margins of cleithra. Branchiostegal rays 7-8 (mode 7; n=35). Total gill rakers on anterolateral margin of first arch 16-23 (mode19;n=28); epibranchial with 5-9 (mode 6) and ceratobranchial with 10-15 (mode 12) long, thin gill rakers.

Maxillary barbels of females and immature males filamentous, thread-like, concealed in groove above premaxilla, length 6.3-16.1% HL (mean=10.1±2.9 SD; n=16). Barbel of prenuptial males ossified at base with filamentous tip, length 27.8-33.7% HL (mean=31.1±2.6 SD; n=4), some specimens with about 3-4 low-crowned, incipient hooks on dorsomedial surface; full armature of peak nuptial male maxillary barbel not observed in material examined.

Dorsal fin rays II,6, consisting of a small spinelet, elongated spine, and branched rays; first ray longest, tip extending anterior to midpoint between dorsal-fin origin and adipose-fin origin when fin is adpressed. Dorsal-fin origin about equal with vertical passing through pectoral-fin insertion. Dorsal-fin spine relatively short, 12.8-19.2% SL (mean=16.1±1.7 SD; n=20), with weak longitudinal ridges on lateral margin. Posterior margin of spine in females and non-nuptial males with 8-17 (mode 10; mean=12.1±2.2 SD; n=58) sharp, retrorse serrae, not quite to base. Posterior margin of spine in pre-nuptial males smooth (Eigenmann, 1912). Anterior margin of spine weakly to moderately crenulated with low-crowned points, in tighter cluster proximally. Full extent of dorsal-fin spine development in peak nuptial males not observed.

Anal fin long, base 30.9-39.3% SL, with 31-38 rays (mode 35; n=73), distal margin nearly straight to slightly convex except in nuptial males. Anal-fin pterygiophores 31- 35 (mode 34; mean=33.2±1.1 SD; n=13). First 6-7 anal-fin rays of prenuptial males elongated and coalesced to form intromittent organ, gonopore displaced near tips of rays.

Pectoral-fin spine well developed, relatively thin, short, 13.9-18.1% SL, not strongly grooved or furrowed. Longest pectoral rays exceed length of spine, tip of adpressed fin falling short of or just reaching to pelvic-fin origin. Anterior margin of spine crenulate. Posterior margin of spine with single series of prominent, sharp, retrorse serrae, counted from both sides in some specimens, range from 8-17 (mode 10; mean=12.0±2.1 SD; n=61). Pectoral fin with 8-9, rarely 6-7 or 10, branched rays (mode 9; n=73). Postcleithral process generally absent, occasionally present as a small rudimentary splint.

Pelvic-fin origin anterior to vertical through tip of longest adpressed dorsal-fin ray; margin of fin straight to slightly rounded. Pelvic fin rays i,6; first branched ray longest, subsequent rays progressively shorter.

Caudal fin deeply forked, lobes equal, with 8+9 principal rays, rarely with 6 upper, 8 lower principal rays; 16-20 (mode 18; n=48) upper and 11-16 (mode 14) lower procurrent rays.

Preanal vertebrae 14-16 (mode 15; n=31). Total vertebrae 39-41 (mode 40; n=31). Pairs of pleural ribs 4-5 (mode 4; n=28).

Pseudotympanum large, ovoid, semi-translucent, epidermis covering muscle hiatus bulging outward and variably pigmented on exterior surface, ranging from nearly hyaline to moderately pigmented, especially on dorsal half ( Figs. 5 , 16 ); projected light visible between sides due to the size and transparency of the gas bladder and thin overlying epidermis. Gas bladder of adult large, cordiform, apple shaped, moderately turgid, smooth-walled on dorsal, lateral, and anteroventral margin; posteroventral margin with an inverted “V” shaped thickened area of tunica with weak to moderate external ridges ( Fig. 6f ). No terminal diverticula. Internal median septum thin, laminar, together with posteroventral margin of gasbladder capsule weakly ossified in adults ( Fig. 17 ).

N Range Mean SD Holotype FMNH 53243 Standard length (SL, mm) 22 30.3-47.5 --- --- 47.3

Percent of SL

Preadipose length 22 77.3-82.1 79.6 1.4 79.3

Preanal length 22 52.5-59.7 54.9 1.9 52.9

Predorsal length 22 28.8-34.4 31.7 1.6 30.7

Prepelvic length 22 41.3-47.0 44.9 1.7 41.9

Prepectoral length 22 23.6-28.3 25.8 1.4 24.9

Pectoral-fin origin to dorsal-fin origin 22 15.2-20.9 18.0 1.6 19.5

Pelvic-fin origin to dorsal-fin origin 22 19.6-25.8 23.5 1.9 19.9

Pelvic-fin origin to adipose-fin origin 22 36.7-50.0 40.0 2.8 40.8

Dorsal-fin origin to adipose-fin origin 22 45.9-55.4 50.0 2.2 51.6

Adipose-fin origin to anal-fin insertion 22 13.5-18.4 16.0 1.3 13.5

Body depth at dorsal-fin origin 22 16.5-24.2 20.3 1.6 16.5

Caudal peduncle depth 22 7.6-10.5 9.6 0.8 7.6

Caudal peduncle length 22 9.6-15.2 11.4 1.4 12.5

Body width at pectoral-fin origin 22 16.8-20.0 18.8 0.9 18.2

Body width at pelvic-fin origin 21 7.6-12.5 10.3 1.5 ---

Pectoral spine length 20 13.9-18.1 16.0 1.2 ---

Anal-fin base length 22 30.9-39.3 36.2 2.1 37.2

Head length (HL) 22 22.2-27.8 24.6 1.6 23.0

Percent of HL

Head depth at supraoccipital 22 54.3-69.7 63.5 4.4 63.3

Head width at postorbitals 22 58.3-79.8 70.7 5.7 63.3

Dorsal interopercular width 22 45.0-63.6 54.9 5.2 50.5

Anterior internarial distance 19 18.9-33.3 26.6 3.9 ---

Preisthmus length 21 63.0-81.8 71.9 4.7 68.8

Snout length 22 31.4-43.6 38.3 3.3 42.2

Gape width 22 34.8-53.6 46.5 4.7 45.0

Upper jaw length 22 25.7-36.5 31.7 2.8 32.1

Lower jaw length 22 25.2-37.5 30.2 3.0 29.4

Eye diameter 22 24.3-35.7 28.8 2.8 28.4

Color in alcohol. The description and illustration in Eigenmann (1912: 204, plate 20, fig. 3; reproduced here in Fig. 16b ) indicates the holotype of T. piperata , as the specific epithet alludes, to originally have relatively uniform “peppered” pigmentation over the head, dorsum, and sides of body, with dense concentrations of melanophores at the base of the caudal fin, base of the dorsal fin, over the pseudotympanum, and tip of the snout. The preserved holotype is now faded, and, due to shrinkage, it is now difficult to discern pigmentation pattern. In freshly collected specimens, the background color is typically tan to beige or dusky yellowish, with many specimens showing sparse traces of pigmentation. In well-pigmented individuals, the dorsum, sides of the body, and the head are covered with diffuse minute brown specks consisting of individual melanophores, occasionally enlarged or coalesced and forming weak spots or slight mottling. A prominent hourglass-shaped vertical bar at the base of the caudal fin, consisting of fine, densely clustered brown or black melanophores, is characteristic of this species ( Fig. 16b ); the leading vertical edge of the bar is nearly straight. Pigment on dorsal aspect of body generally confined to a relatively narrow stripe, sometimes broken into irregular patches, extending down midline of back and with scattered specks distributed ventrally above lateral line and over pseudotympanum. Venter generally depigmented, occasionally with melanophores dispersed on chin, isthmus, and lower portion of opercula and body near pectoral-fin base. Top and sides of head moderately and irregularly pigmented, with some light areas around nares, between orbits, and on lower half of opercula. Skin above supraoccipital generally brownish, somewhat more intense at base of dorsal spine. Pigment extending along part or most of anterior margin of the dorsal spine. Dorsal fin only lightly pigmented, occasionally with distal tips of rays darkened. Adipose and distal portion of caudal-fin lobes hyaline or only lightly speckled. Anal fin generally with little pigment, but in some specimens with thin black margin, most intense at distal tips of anterior rays. Pectoral and pelvic fins dusky, with melanophores concentrated along anterior rays and interradial membranes, near base, and occasionally along distal margin of fin.

Distribution. Tympanopleura piperata is distributed in the Essequibo River drainage of Guyana, including the Potaro and Rupununi rivers, and in the central and upper Amazon River basin in Brazil and Peru ( Fig. 15 ).

Remarks. Eigenmann (1912) designated as cotypes of T. piperata two males and five females (ex. CM 1709a and IU 12090), 57-61 mm, presumably TL. Based on examination of external morphology and radiographs of the paratypes, i. e., ossification of the maxillary barbel and anterior anal-fin rays, we provisionally identify the extant type series, excluding the holotype, to consist of four males and two females; a seventh specimen was not located in museum material examined. Given the small size of the species and difficulty in accurately determining gender of specimens in the absence of pronounced sexually dimorphic features, we conclude that Eigenmann erred in assigning sex to some of the type specimens; confirmation of this would require dissection of the gonads. The holotype (FMNH 53243) and one cotype (FMNH 53244) appear to have been desiccated or exposed to circumstances that caused severe shrinkage and are in poor condition. Etymology of the specific epithet is derived from the Latin piper, meaning pepper, in reference to the finely stippled pigmentation pattern on the body.

Material examined. Holotype. FMNH 53243 (ex CM 1708 ), 1 (47.3 mm SL, male), British Guiana (= Guyana), Cuyuni-Mazaruni Region, Essequibo River at Crab Falls , 1908, C.H. Eigenmann and party . Paratypes. 6 specimens (41.7-47.5 mm SL). FMNH 53244 (ex CM 1709 a or IU 12090 ), 1 (41.7 mm SL, male [?]), same collection data as holotype . CAS 58382 (ex IU 12090 ), 3 (1, 47.5 mm SL, female [?]; 2, 44.6-46.9 mm SL, males), same collection data as holotype . MCZ 30189 (ex CM 1709 a or IU 12090 ), 1 (46.4 mm SL, female), same collection data as holotype . BMNH 1911.10 .31.102 (ex CM 1709 a or IU 12090 ), 1 (44.8 mm SL, male), same collection data as holotype .

Non-type material. 364 specimens (23.0- 56.3 mm SL). Brazil. Amazonas : ANSP 137688 , 1 (40.4 mm SL), W of Moura near junction of rio Negro and rio Branco , date unknown, J. Faughn ; ANSP 194018 , 2 (34.9-40.8 mm SL), rio Jutaí between Porto Antunes and Foz do Jutai, c. 02°50’6.1”S 66°55’38.9”W, 13 Nov 1993, J.P. Sullivan et al .; ANSP 194019 , 3 (36.9-42.5 mm SL), rio Jutaí downriver of Porto Antunes and upriver of Copatana , c. 02°58’9.0”S 67°00’43.6”W, 16 Nov 1993, O . T. Oyakawa et al .; ANSP 194020 , 1 (42.5 mm SL), rio Jutaí downriver of Porto Antunes and upriver of Foz do Jutai , c. 02°57’3.8”S 67°00’48.5”W, 16 Nov 1993, J.P. Friel et al .; ANSP 194021 , 1 (39.9 mm SL), same collection data as ANSP 194019; ANSP 194022 , 5 (43.2-47.5 mm SL), rio Negro 34.3 km downriver of Moura, 9.8 km upriver of Novo Caioé , c. 01°42’16.0”S 61°29’56.1”W, 11 Dec 1993, J.N. Baskin etal .; INPA 10263 , 1 (41.4 mm SL), rio Negro, Novo Airão, Lago do Prato , collected with bottom trawl, c. 02°36’S 60°56’W, 17 Mar 1991, M. Garcia ; INPA 12562 , 4 (30.7-37.2 mm SL), rio Negro, rio Jaú, Copaíba pool, c. 02°39’S 60°59’W, 15 Oct 1995, M. Garcia ; INPA 12564 , 13 (33.9-41.7 mm SL), rio Negro, rio Jaú, Copaíba pool, 15 Oct 1995, M. Garcia ; INPA 12584 , 5 (26.8- 30.3 mm SL), rio Negro, rio Jaú, lake at mouth of rio Paunini , 17 Jun 1995, M. Garcia ; INPA 12603 , 11 (24.4-31.6 mm SL), same locality as INPA 12584, 19 Jun 1995, M. Garcia; INPA 12608 , 8 (25.2-30.7 mm SL), rio Negro, rio Jaú, lake above rio Paunini , 18 Jun 1995, M. Garcia ; INPA 12613 , 4 (27.5-50.7 mm SL), same collection data as INPA 12608; INPA 12636 , 158 (31.2-56.3 mm SL, 1 c/s), rio Negro, rio Jaú, Lago Tambor Velho, 15 Oct 1995, M. Garcia ; INPA 12682 , 39 (40.8-50 mm SL, 1 c/s), rio Negro, rio Jaú, canal Miratuca , 28 Oct 1995, M. Garcia ; MZUSP 114006 , 5 (29.0- 32.8 mm SL), rio Jauaperi approximately 30 km from the mouth, 19 Nov 1968 , T. Roberts ; MZUSP 56199 , 1 (unmeasured), rio Negro 1.3 km below Jufarí, c. 01°15’S 68°58’W, 9 Dec 1993, J.G. Lundberg et al .; MZUSP 56200 , 3 (unmeasured), rio Jutaí between rio Solimões and rio Zinho, c. 03°05’S 67°14’W, 16 Nov 1993, J.G. Lundberg et al .; MZUSP 56724 , 1 (unmeasured), rio Jutaí between rio Solimões and rio Zinho, 16 Nov 1993, O. Oyakawa et al. Rondônia : UNIR 1589 , 20 (41.1-54.0 mm SL), rio Madeira, rio Jaci Paraná, Jaci Paraná, beach in front of Lago Madalena, c. 09°17’12’’S 64°24’00’’W, 10 Dec 2008, C. P. Röpke . Guyana. Upper Demerara Berbice : INHS 49234 , 4 (26.5-31.0 mm SL), Essequibo River 0.72 mi SW Rockstone at sandbar, 19 Oct 1998, M.H. Sabaj Pérez et al .; INHS 49357 , 3 (29.6-32.4 mm SL), large sandbar and small cataract 31.9 mi SSW Rockstone , bearing 204°, c. 05°31’39.5”N 58°37’43.6”W, 21 Oct 1998, M.H. Sabaj Pérez et al .; INHS 49443 , 1 (32.5 mm SL), beach on N bank downriver of Tumatumari cataract, c. 05°21’48.4”N 59°00’04.4”W, 22 Oct 1998, M.H. Sabaj Pérez et al .; UF 181564 (ex. MCZ 50742 ), 1 (33.5 mm SL, c/s), North Rupununi, Mobay Pond , c. 05°10’0.01”N 58°37’59.9”W, 4 May 1971, C.D. Hopkins & F. Cichocki. Potaro-Siparuni : ANSP 175838 , 1 (46.4 mm SL), Essequibo River at Essequibo campsite (=WGS97-15), 26 Jan 1997, D. Torres et al. Upper Takutu-Upper Essequibo : ANSP 179676 , 2 (33.7-38.4 mm SL), Rupununi River, sand beach and inlet at Karanambo Ranch , 29 Oct 2002, M.H. Sabaj Pérez et al . Peru. Loreto: ANSP 191444 , 4 (42.5- 37.4 mm SL), río Nanay above Santa Clara , c. 03°46’45”S 73°22’06”W, 14 Aug 2003, M. Sabaj etal .; ANSP 191445 , 5 (32.5-35.0 mm SL), río Nanay, village of Pampa Chica, 4.5 km from Iquitos , c. 03°45’09”S 73°17’00”W, 18 Aug 2003, M. Sabaj Pérez et al .; INHS 36738 , 5 (40.0- 44.8 mm SL, 1 c/s), río Nanay and tributary, Santa Clara , W of Iquitos, 22 Jul 1995, L.M. Page et al .; INHS 44201 , 20 (23.0- 44.2 mm SL, 5 c/s), río Nanay upriver from Santa Clara at Mizplaya , 13.9 km W of Iquitos, c. 03°46’54.6”S 73°21’49.6”W, 29-30 Jul 1997, M.H. Sabaj Pérez et al .; MZUSP 115006 , 2 (38.1-38.4 mm SL), same data as INHS 44201; SIUC 29483 , 1 of 6 (32.4 mm SL), río Nanay at Misplaya, just upriver from Santa Clara , 13.9 km (78° bearing) from Iquitos , c. 03°46’54.6”S 73°21’49.6”W, 29-30 Jul 1997, M.H. Sabaj Pérez et al .; SIUC 29510 , 11 (25.5-32.3 mm SL), same data as SIUC 29483; SIUC 29880 , 3 (27.8-39.0 mm SL), río Nanay at Pampachica, 4.5 km from Iquitos center (269° bearing), c. 03°45’8.8”S 73°17’00.1”W, 11 Aug 1997, M.W. Littmann & R.E. Weitzell ; UF 185774 , 10 (31.5-39.3 mm SL), same data as SIUC 29483; UF 185775 , 6 (38.5-43.5 mm SL, 1 c/s), río Nanay at Santa Clara near Iquitos , 22 Jul 1995, B.M. Burr et al .

Tympanopleura rondoni (A. Miranda Ribeiro, 1914) Figs. 1f , 2 , 6g , 18

Ageneiosus rondoni A. Miranda Ribeiro, 1914: 12-13 [type-locality: Brazil, rio Negro, Manáos (=Manaus); syntypes MNRJ 962, 2]. - Miranda Ribeiro, 1953 [type specimens listed; lectotype designated]; -Miranda Ribeiro, 1962: 4 [catalog of MNRJ material, only 1 specimen cited ( MNRJ 962)]. - Gosline, 1945: 25 [citation]. - Fowler, 1951: 453, fig. 480 [partial synonymy; distribution; figure possibly based on T. atronasus ]. - Santos, 1954: 123-124, fig. 64 [reference]. - Burgess 1989: 286 [citation]. - Ferraris, 2003: 471 [checklist; as synonym of Ageneiosus brevis after Walsh, 1990; type-locality; lectotype designation by Miranda Ribeiro, 1953]. - Ferraris, 2007: 69 [type checklist; as synonym of A. brevis after Walsh, 1990; information duplicated from Ferraris, 2003].

Ageneiosus madeirensis Fisher 1917: 426-427 , pl. 42 [type-locality: San Joaquin, Bolivia; comparisons with Ageneiosus ucayalensis and A. valenciennesi ]. - Henn, 1928: 74 [holotype listed]. - Gosline, 1945: 24 [citation]. - Fowler, 1951: 452- 453, fig. 479 [partial synonymy; distribution]. -Lauzanne & Loubens, 1985: 111 [checklist of species from rio Mamoré]. -Ibarra & Stewart, 1987: 6, 86 [type specimens listed]. - Burgess, 1989: 285-286 [citation; illustration after Fisher 1917, erroneously attributed to Eigenmann, 1917]. - Lauzanne et al., 1991: 68 [annotated checklist of species from Bolivian Amazon; Région de Trinidad; Itenez (Guaporé); identification not verified]. - Willink et al., 1999: 104 [in checklist of species from Bolivian Amazon, after Lauzanne etal., 1991].- Chernoff et al., 2000: 281 [in table of species from Bolivian Amazon, after Lauzanne et al., 1991 and Willink et al., 1999]. - Ten et al., 2001: 103 [checklist; Bolivia, Reserva Inmovilizada Iténez, río San Martin, río Iténez; identification not verified]. - Ferraris, 2003: 471 [checklist; as synonym of A. brevis after Walsh, 1990; type-locality; holotype]. - Ferraris, 2007: 69 [type checklist; as synonym of A. brevis after Walsh, 1990; information duplicated from Ferraris, 2003].

Diagnosis. Tympanopleura rondoni has a more robust body shape and reaches a larger maximum size (about 160 mm SL) than congeners (all less than 120 mm SL in the material examined). In addition, T. rondoni has a unique, prominently spotted pigmentation pattern on the head, body, and fins, and an elongated gas bladder with two moderately long, recurved terminal posterior diverticula. Tympanopleura rondoni further differs from T. atronasus in having a greater number of anal-fin rays (28-37, mode 31 vs. 23-30, mode 27), more pectoral-fin rays (10-13 vs. 7-9), more gill rakers on the first arch (24-33 vs. 14-23), fewer preanal vertebrae (14-16, mode 15 vs. 16-19, mode 17), fewer pairs of pleural ribs (4-6 vs. 7-8), greater distance from pectoral- to dorsal-fin origin (19.8-29.0% SL vs. 15.7-20.9% SL), slightly greater body width at pectoral-fin origin (21.8-29.5% SL vs. 17.8-22.9% SL), slightly longer pectoral-fin spine (17.1-21.0% SL vs. 13.3-19.0% SL), and a smaller eye diameter (8.4-17.0% HL vs. 16.0-27.8% HL). Tympanopleura rondoni differs from T. brevis in having more gill rakers (24-33, mode 29-30 vs. 20-24, mode 23), a slightly shorter-pectoral fin spine (17.1-21.0% SL vs. 19.1- 24.4% SL), and a smaller eye (8.4-17.0% HL vs. 13.8-21.0% HL); otherwise, these two species are differentiated mainly on the basis of pigmentation pattern and structure of the gas bladder. Tympanopleura rondoni differs from T. cryptica in having a longer anal fin (anal-fin rays 28-37, mode 31 vs. 23-30, mode 29), more pectoral-fin rays (10-13, mode 11 vs. 8-10, mode 9), more gill rakers (24-33, mode 29-30 vs. 21-26, mode 22), greater number of total vertebrae (38- 42, mode 40 vs. 38-41, mode 38), pleural rib pairs (4-6, mode 6 vs. 4-5, mode 5), and a smaller eye (8.4-17.0% HL vs. 16.7-25.6% HL). Tympanopleura rondoni differs from T. longipinna in having a somewhat shorter anal fin (anal-fin rays 28-37, mode 31 vs. 32-42, mode 37), more gill rakers (24-33, mode 29-30 vs. 19-25, mode 23), fewer total vertebrae (38-42, mode 40 vs. 40-43, mode 43), pleural rib pairs (4-6, mode 6 vs. 4-5, mode 5), longer predorsal length (35.2-47.4% SL vs. 29.5-36.1% SL), shorter distance from pelvic- to adipose-fin origin (24.0-41.5% SL vs. 37.6-45.1% SL), shorter distance from dorsal- to adipose-fin origin (38.1-46.8% SL vs. 46.5-54.0% SL), and a shorter anal-fin base (23.1-32.5% SL vs. 33.9-39.9% SL). Tympanopleura rondoni differs from T. piperata in having more pectoral-fin rays (10-13, mode 11 vs. 6-10, mode 9), more gill rakers (24-33 vs. 16-23), pleural ribs pairs (4-6, mode 6 vs. 4-5, mode 4), longer prepectoral length (29.2-39.0% SL vs. 23.6-28.3% SL), greater distance from pectoral- to dorsal-fin origin (19.8-29.0% SL vs. 15.2-20.9% SL), greater body width at pectoral-fin origin (21.8-29.5% SL vs. 16.8-20.0% SL), shorter anal-fin base (23.1-32.5% SL vs. 30.9-39.3% SL), longer head (26.5-39.0% SL vs. 22.2-27.8% SL), longer snout (41.7-53.6% SL vs. 31.4-43.6% SL), proportionally longer jaws and a wider gape, and a smaller eye (8.4-17.0% HL vs. 24.3-35.7% HL).

Description. Morphometric data are provided in Table 13. Tympanopleura rondoni is a medium-sized auchenipterid. Size range 32.8-160.4 mm SL (n=56) for female and non-nuptial male specimens. Size range 90.7-127.8 mm SL (n=12) for pre-nuptial and nuptial males. Head moderately depressed and broad. Dorsal profile from tip of snout to top of supraoccipital nearly straight, ascending and weakly convex posteriorly to dorsal-fin origin. From dorsal-fin insertion to base of upper caudal-fin lobe nearly straight to convex. Ventral contour of head and abdomen straight to weakly convex. Body compressed, widest at pectoral-fin origin, 21.8-29.5% SL, gently tapered posteriorly from pectoral-fin insertion to base of caudal fin. Caudal peduncle moderately deep, 7.1-9.9% SL.

Head length 26.5-39.0% SL. Mouth inferior, upper jaw projecting anterior to tip of lower jaw approximately the width of the premaxillary tooth patch. Snout long, 41.7- 53.6% HL, broadly crescentic in dorsal or ventral profile. Premaxillary and dentary tooth bands broad, with 5-7 irregular rows of teeth at midline, tapered to about 3-5 rows posterolaterally; teeth single cusped, moderately long, sharp, recurved. Midline area of dentary near symphsis elevated, teeth projected slightly outward. Eye small, 8.4- 17.0% HL, slightly more visible dorsally than ventrally, covered with thick, opaque epidermis ( Fig. 1f ). Fontanelle groove long and deep, extending posterior to eyes, bound on either side by high ridges; dorsal surface of frontals, supraoccipital, nuchal shield rugose, ornamented with network of ridges and granulations. Anterior nares lateral to tips of mesethmoid wings, directed anteriorly; posterior nares lateral to frontals, directed upward, with short flap of epidermis surrounding margin. Posterior edge of lower jaw extending posteriorly to or slightly beyond midpoint of eye. Gill membranes broadly fused to isthmus along anterolateral margin of cleithrum. Branchiostegal rays 8-10 (mode 9; n=55). Total gill rakers on anterolateral margin of first arch 24-33 (mode 29; n=47); epibranchial with 8-10 (mode 9) and ceratobranchial with 16-24 (mode 19) gill rakers. Gill rakers long, those near middle of arch about 4-7% HL, crenulate on ventromedial margin, gradually reduced in length anteriorly.

N Range Mean SD Lectotype MNRJ 962 (1) Standard length (SL, mm) 30 37.8-160.4 --- --- 160.4

Percent of SL

Preadipose length 30 77.4-83.5 80.4 1.6 80.2

Preanal length 30 52.4-69.5 64.7 4.0 64.1

Predorsal length 30 35.2-47.4 39.8 2.4 37.6

Prepelvic length 30 43.3-56.2 52.1 3.1 52.6

Prepectoral length 30 29.2-39.0 35.1 2.5 34.9

Pectoral-fin origin to dorsal-fin origin 30 19.8-29.0 23.9 2.1 22.3

Pelvic-fin origin to dorsal-fin origin 30 10.3-28.6 24.5 3.5 25.9

Pelvic-fin origin to adipose-fin origin 30 24.0-41.5 32.8 3.2 32.3

Dorsal-fin origin to adipose-fin origin 30 38.1-46.8 42.3 2.2 45.1

Adipose-fin origin to anal-fin insertion 30 9.2-16.7 14.8 1.6 14.1

Body depth at dorsal-fin origin 30 18.5-24.8 21.9 1.6 21.2

Caudal peduncle depth 30 7.1-9.9 8.8 0.7 9.3

Caudal peduncle length 30 9.4-12.5 10.9 0.9 12.5

Body width at pectoral-fin origin 30 21.8-29.5 26.5 2.3 25.0

Body width at pelvic-fin origin 30 9.4-13.9 11.5 1.1 11.7

Pectoral spine length 30 17.1-21.0 19.1 1.0 19.6

Anal-fin base length 30 23.1-32.5 26.0 2.4 26.1

Head length (HL) 30 26.5-39.0 35.0 3.1 33.7

Percent of HL

Head depth at supraoccipital 30 44.9-66.9 53.3 5.1 50.2

Head width at postorbitals 30 55.7-80.3 68.7 4.9 76.9

Dorsal interopercular width 30 42.9-54.3 46.8 2.9 47.6

Anterior internarial distance 30 31.0-36.9 33.9 1.7 35.2

Preisthmus length 30 61.0-78.0 68.3 4.1 72.2

Snout length 30 41.7-53.6 47.8 3.3 53.0

Gape width 30 51.0-65.6 58.0 3.4 65.6

Upper jaw length 30 32.6-45.5 37.2 2.9 42.2

Lower jaw length 30 29.2-40.7 33.3 2.7 36.1

Eye diameter 30 8.4-17.0 12.8 1.8 12.2

Maxillary barbel of females and non-nuptial males small, ossified at base, filiform, concealed in premaxillary groove, 9.6-26.8% HL (mean=16.2±4.1 SD; n=25); groove extending obliquely to midpoint between corner of mouth and front of eye. Maxillary barbel of prenuptial and nuptial males ossified most or all of length, thickened, elongated, 30.1-38.6% HL (mean=34.0±2.3 SD; n=12). Barbel of prenuptial males smooth, with a fleshy tip, covered with thin epidermis, and lacking hooks altogether or with few (about 6-8) small, blunt, incipient hooks beginning development on anterodorsal surface. Maxillary barbel of nuptial male with 10-17 (n=3, including left and right in one specimen) sharply pointed, recurved hooks, modally 9 on anterodorsal margin, 4-10 on ventromedial margin; entire barbel with thick epidermal sheath covering all but tips of hooks.

Dorsal fin rays II,6, consisting of a small spinelet, elongated spine, and branched rays; first ray longest, subsequent rays progressively shorter. Dorsal-fin origin about equal with or slightly posterior to vertical passing through pectoral-fin insertion. Dorsal-fin spine relatively long and stout in females and non-nuptial males, length 17.2-25.0% SL (mean=19.8±2.2 SD; n=17). Anterior margin of spine variable, from nearly smooth to strongly crenulated proximally; spine most rugose in larger individuals. Posterior margin of spine in all but nuptial males with 15- 38 relatively short, conical, retrorse serrae. Dorsal spine of nuptial male robust, greatly elongated, sinusoidal, anterior margin convex over basal half, inflected posteriorly near midpoint, convexagaindistally,tipslightlycurvedlaterally; length of spine in pre-nuptial and nuptial males 25.5-40.9% SL (mean=30.6±4.3 SD; n=10). Prominent antrorse serrae on anterior margin of spine in pre-nuptial and nuptial males; serrae shorter and relatively blunt proximally early in development of armature, becoming long, thin, recurved, and alternating laterally over distal half, embedded in thick sheath of epidermis. Lateral margins of spine with pronounced longitudinal ridges and deep furrows, obliquely distributed along length of spine, heavily pigmented. Posterior margin of spine in fully nuptial males smooth. Adipose fin relatively large, entire base well anterior to vertical through anal-fin insertion, posterior margin free.

Anal fin relatively short, base 23.1-32.5% SL, with 28- 37 rays (mode 31; n=63); distal margin rounded. Anal-fin pterygiophores 27-36 (mode 29; n=45). First 5-6 anal-fin rays of pre-nuptial and nuptial males thickened, elongated, unbranched, coalesced to form intromittent organ.

Pectoral-fin spine robust, relatively long, 17.1-21.0% SL, short of or just reaching to pelvic-fin origin. Anterior margin of spine weakly crenulated proximally. Dorsal and ventral surfaces of spine with prominent, irregular longitudinal ridges and furrows. Posterior margin of spine with single series of short, conical, retrorse serrae, counted on one or both sides, ranging from 12-29 (mode 20-22; mean=19.0±4.9 SD; n=25). Pectoral fin with 10-13 branched rays (mode 11; n=59); anterior rays longest, distal margin of fin straight to very slightly falcate. Postcleithral process moderately well developed, robust, conical, occasionally absent.

Pelvic-fin origin anterior to vertical through tip of longest adpressed dorsal-fin ray; margin of fin straight to slightly convex. Pelvic fin rays i,6; first branched ray longest, subsequent rays progressively shorter.

Caudal fin forked, lobes equal, with 8+9 principal rays, 16-26 (mode 23; n=27) upper and 15-18 (mode 17; n=27) lower procurrent rays.

Preanal vertebrae 14-16(mode15;n=46).Total vertebrae 38-42 (mode 40; n=46). Pairs of pleural ribs 4-6 (mode 6; n=39).

Gas bladder of adult large, unencapsulated, elongated antero-posteriorly in comparison to congeners, moderately turgid, smooth-walled on external surfaces, with two moderately elongated fleshy terminal diverticula, close at their bases and typically recurved anteriorly in body cavity ( Fig. 6g ).

Color in alcohol. Background color tan, dusky yellow, or whitish purple, obscured in many specimens by dark pigmentation over most of dorsum. Distinctive pigmentation pattern consisting of dark brown to black irregular spots (usually 1-2 mm in diameter) over most of body, usually heavily concentrated on head and upper half of body. Spots consisting of coalesced melanophores and often obscured on head and dorsum by additional dense speckles of pigmentation. Spots on body sometimes forming irregular rows along midline of back, sides above the lateral line, and a lower row extending posteriorly from above the pectoral-fin base. Skin lateral to gas bladder darkly pigmented. Venter generally lightly pigmented with specks sometimes near tip of chin and extending along lateral branchiostegal membranes and near pectoral fin. Top of head with dense background of brown or black pigmentation overlain with spots. Leading edge of dorsal-fin spine brown to black; rays of dorsal fin with pigmentation at base and near tips, most heavily concentrated on anterior rays. Adipose fin with uniformly distributed melanophores, more evident near base. Caudal peduncle and base of caudal-fin rays darkly pigmented with a few specks scattered along rays and interradial membranes, sometimes with additional concentrations of pigment at tips of rays. Anal fin with dark margin and some specks scattered along base. Pectoral and pelvic fins pigmented on dorsal surface, most heavily along base, over first few anterior-most rays, and along ray tips forming a distinctive black or brown marginal edge.

Distribution. Tympanopleura rondoni is broadly distributed in the central Amazon River basin, including the rio Madeira in Brazil, and the río Mamoré and río Guaporé in Bolivia ( Fig. 19 ).

Remarks. Miranda Ribeiro (1953) cited two cotypes and designated “Lectótipo-A,” presumably to fix the name by designating as a lectotype the larger of the two specimens in the type series. However, in a subsequent type catalog, Miranda Ribeiro (1962) referred to only one specimen, listed under MNRJ 962. The specific epithet is a patronym named in honor of Cândido Mariano da Silva Rondon (1865- 1958), famous Brazilian Army Marshal (“Marechal”), pioneering telegraph engineer, patriot, zealous explorer, and protector of indigenous tribes.

Material examined. Lectotype. MNRJ 962 A, 1 (160.4 mm SL, presumed female). Type-locality: Brazil, rio Negro , Manáos (=Manaus), 1908, Miranda Ribeiro . Paralectotype. MNRJ

962, 1 (134.4 mm SL, presumed female). Same collection data as lectotype. Other types. 15 specimens (32.8-108.3 mm SL). FMNH 58143, 1 (102.4 mm SL, male), holotype of Ageneiosus madeirensis , Bolivia, río Mamoré, San Joaquin, 6 Sep 1909, J.D. Haseman. FMNH 58144, 14 (32.8-108.3 mm SL, 1 c/s, paratypes of A. madeirensis ), same collection data as holotype.

Non-type material. 102 specimens (40.0- 165.4 mm SL). Bolivia. Beni : MZUSP 27805 , 3 (79.5-110.8 mm SL), Laguna San José, Trinidad , Sep 1983 , Conv. Pisc. ORSTOM-UTB; MZUSP 114008 (ex MZUSP 27818 ), 2 (51.2-55.7 mm SL), Trinidad, canal San Gregorio , Sep 1983 , Conv. Pisc. ORSTOM-UTB; MZUSP 37880 , 1 (124.4 mm SL), Igarape Beem, Humaitá , Jul 1975 , U. Caramaschi et al.; UF 185776 , 2 (119.6-124.0 mm SL), same data as MZUSP 27805 ; UF 185777 , 1 (69.0 mm SL), same data as MZUSP 114008. Locality unknown : INPA 652 , 2 (106.8-117.6 mm SL), Sep 1983 , G. Loubens & L. Lauzanne . Brazil. Amazonas : ANSP 193989 , 2 (63.3-77.0 mm SL), rio Purus , c. 03°58’47.2”S 61°29’06.2”W, 27 Jul 1996 , M. Toledo-Piza et al.; ANSP 194014 , 5 (52.7-145.7 mm SL), rio Purus , c. 03°59’06.5”S 61°29’20.7”W, 27 Jul 1996 , M. Toledo-Piza et al.; ANSP 194015 , 9 (40.0- 75.3 mm SL), rio Purus along Ilha Tatu , c. 03°59’26.9”S 61°29’37.7”W, 27 Jul 1996 , M. Toledo-Piza et al.; ANSP 194016 , 5 (99.3-124.7 mm SL), rio Solimões 35.5 km downriver of Santa Maria, 20.6 km upriver of Itacoatiara , c. 03°15’45.2”S 58°36’01.4”W, 20 Oct 1994 , F.G. Langeani et al.; CAL unk., 1 (84.6 mm SL), rio Solimões 67.0 km downriver of Bela Vista, 26.0 km upriver of Manaus , c. 03°11’28.2”S 59°53’45.9”W, 23 Oct 1993 , S.L. Jewett et al. (SLJ-93-005); CAL unk., 2 (71.5-83.7 mm SL), rio Solimões 23.5 km downriver of Santa Maria, 21.1 km upriver of Itacoatiara , c. 03°17’16.0”S 58°35’23.1”W, 20 Oct 1994 , J.G. Lundberg et al. (JGL-94-067); INPA 11758 , 1 (160.9 mm SL), rio Solimões, Ilha do Careiro, Paraná do Rei , 27 Feb 1986 , B. Merona; INPA 11759 , 5 (117.2-165.4 mm SL), rio Solimões, Ilha do Caraeiro, Jul / Oct 1986 , INPA ichthyology team; INPA 13393 , 1 (111.1 mm SL), rio Solimões, Ilha da Marchantaria , 4 Feb 1993 , P. Petry & R. Sotero ; INPA 18960 , 2 (91.7-92.4 mm SL), rio Solimões, Paraná Maiana, Mamirauá Reserve , 9 Sep 1999 , W.G. R. Crampton ; INPA 18961 , 1 (115.7 mm SL), rio Japurá, margin of Mamirauá Reserve , 2 Feb 2000 , W.G. R. Crampton ; INPA 22139 , 7 (113.8-156.0 mm SL), rio Solimões, Lago do Rei , 31 Jan 2001 , L.H. Rapp Py-Daniel et al.; INPA 22802 , 5 (139.9-158.2 mm SL), rio Solimões, Lago do Rei, Lago Mingau, 24 Feb 1986 , B. Merona et al.; INPA 25757 , 1 (156.3 mm SL), rio Solimões, Lago Muratu, approximately 60 km from confluence with rio Negro , c. 03°20’51”S 60°12’34”W, Apr 2003 , M. Vega; INPA 25819 , 1 (140.3 mm SL), rio Solimões, Lago Muratu, approximately 60 km from confluence with rio Negro , c. 03°20’51”S 60°12’34”W, Jul 2003 , M. Vega; INPA 26537 , 1 (115.6 mm SL), rio Negro, Manaus, near confluence with the rio Solimões , 18 Jun 2006 , J. Zuanon & A. Akama ; INPA 34087 , 2 (110.9-129.0 mm SL), rio Negro, Manaus, Lago Catalão, 8 Aug 2008 , F. R. V. Ribeiro ; MCP 29875 , 2 (103.9-139.5 mm SL), rio Solimões, Alvarães, Caborini beach, near confluence with rio Solimões and rio Japurá , c. 03°09’34”S 64°46’35”W, 7 Feb 2001 , W.G. R. Crampton ; MCP 29876 , 2 (97.7-109.1 mm SL), same location as MCP 29875, 12 Feb 2001 , W.G. R. Crampton ; MCP 29877 , 1 (88.0 mm SL), rio Solimões, Alvarães, Ilha de Içé , c. 03°16’36”S 64°41’01”W, Jan 2001 , W.G. R. Crampton ; MPEG 10048 , 1 (unmeasured), Manacapuru, Lago Piranha floodplain, 11 Mar 2006 , L. Montag & A. Hercos ; MZUSP 114007 , 4 (103.8- 116.6 mm SL), rio Solimões, Lago Janauaca and surroundings, Nov 1976 - Jan 1977 , Alpha Helix expedition; MZUSP 27616 , 1 (127.8 mm SL), rio Solimões, mouth of rio Iça, Santo Antônio do Iça , 13 Oct 1982 , L.P.S. Portugal; MZUSP 56649 , 1 (73.1 mm SL), rio Purus, Berurí , 27 Jul 1996 , M. T. Piza et al .; MZUSP 56656 , 1 (75.6 mm SL), rio Amazonas , c. 03°19’32”S 58°51’54”W, 5 Aug 1996 , M. T. Piza et al .; MZUSP 56660 , 1 (94.4 mm SL), rio Purus , c. 04°03’48”S 61°33’49”W, 27 Jul 1996 , M. T. Piza et al .; MZUSP 57697 , 1 (63.7 mm SL), rio Purus , 15 km below Lago do Estopa, 27 Jul 1996 , F.G. Langeani et al.; MZUSP 75400 , 1 (116.5 mm SL), rio Solimões, stream on the right bank of the Lago Janauacá channel, c. 3°22’S 60°11’W, 11 Jan 1977 , Alpha Helix expedition. Pará : INPA 22722 , 2 (115.0-116.0 mm SL), rio Amazonas, Monte Alegre, Lago Grande de Monte Alegre , 12 Aug 1992 , G. Santos & J. Zuanon ; MZUSP 7862 , 7867-7874 , 9 (86.2-117.6 mm SL), Parana Jacari, municipality of Faro , 13 Dec 1967 , Expedição Permanente da Amazônia ( EPA) ; UF 185778 (ex MZUSP 7863-7866 , 4 (98.9- 112.4 mm SL), same data as MZUSP 7862, 7867-7874. Rondônia : INPA 21720 , 1 (117.7 mm SL), rio Madeira, rio Cautário, Vale do Guaporé , 14 Jul 2003 , G. Torrente-Vilara; UFRO-I 682 , 2 (53.3- 95.6 mm SL), rio Madeira , date & collectors unknown ; UNIR 669 , 8 (68.9-100.1 mm SL), rio Madeira , date & collectors unknown .

Figures

Fig. 1. Dorsal and ventral head profiles of species of Tympanopleura: (a) T. atronasus, INHS 106400 (82.4 mm SL); (b) T. brevis, ANSP 194010 (63.3 mm SL); (c) T. cryptica, INHS 40163 (84.9 mm SL); (d) T. longipinna, MZUSP 114000 (73.0 mm SL, holotype); (e) T. piperata, ANSP 194022 (45.6 mm SL); (f) T. rondoni, ANSP 194015 (75.3 mm SL). Scale bars: a-d, f = 1 cm; e = 5 mm.

Fig. 5. Pseudotympanum (arrow) in Tympanopleura piperata, INHS 36738 (41.5 mm SL).

Fig. 6. Gas bladders of species of Tympanopleura in ventral view: (a) T. atronasus, INHS 106400 (79.9 mm SL); (b) T. atronasus, FMNH 93488 (107.3 mm SL); (c) T. brevis, SIUC 39913 (59.4 mm SL); (d) T. cryptica, INHS 40163 (60.5 mm SL); (e) T. longipinna, MZUSP 34417 (50.5 mm SL); (f) T. piperata, ANSP 194019 (42.5 mm SL); (g) T. rondoni. MZUSP 7862 (117.6 mm SL). Scale bars: a-e = 5 mm; f = 2 mm; g = 10 mm.

Fig. 16. Tympanopleura piperata. (a) ANSP 194022 (47.5 mm SL), female, rio Negro, Amazonas State, Brazil; (b) holotype, FMNH 53243 (ex. CM 1708; 47.3 mm SL), male, Essequibo River, Cuyuni-Mazaruni Region, Guyana, reproduced from Eigenmann (1912; originally cited as 64 mm TL).

Fig. 17. Ossification of the median septum and tunica of the gas bladder in Tympanopleura piperata. (a) UF 181564 (33.5 mm SL), cleared/stained; (b) INHS 36738 (40.0 mm SL), nuptial male, radiograph. Scale bars = 5 mm.

Fig. 15. Distribution of Tympanopleura longipinna (stars) and T. piperata (inverted triangles) based on material examined. Open symbols indicate type localities. Some symbols represent more than one lot or locality.

Fig. 2. Neurocranium of Tympanopleura rondoni in dorsal view, FMNH 58144 (50.3 mm SL; paratype of Ageneiosus madeirensis). Abbreviations: epo, epioccipital; epo-p, posterior process of epioccipital. fro, frontal; io, infraorbital; let, lateral ethmoid; mes, mesethmoid; mnp, median nuchal plate; nas, nasal; pal, autopalatine; pma, premaxilla; pnp, posterior nuchal plate; pto, pterotic; scl, posttemporalsupracleithrum; soc, supraoccipital; sph, sphenotic. Scale bar = 5 mm.

Fig. 18. Tympanopleura rondoni. UF 185776 (124.0 mm SL), nuptial male, río Mamoré, Beni Department, Bolivia.

Fig. 19. Distribution of Tympanopleura rondoni based on material examined. Open triangle indicates type-locality.