Tometes camunani, Andrade & Giarrizzo & Jégu, 2013

Andrade, Marcelo C., Giarrizzo, Tommaso & Jégu, Michel, 2013, Tometes camunani (Characiformes: Serrasalmidae), a new species of phytophagous fish from the Guiana Shield, rio Trombetas basin, Brazil, Neotropical Ichthyology 11 (2), pp. 297-306 : 298-302

Tometes camunani , new species

Fig. 1

Utiaritichthys sp. : Ferreira, 1993: 24 ( Brazil, Pará, rio Trombetas basin; species caught upstream of the Cachoeira Porteira).

Holotype. MPEG 23447 , 224.3 mm SL, Brazil, Pará, Trombetas basin, rio Erepecuru, upstream of the Cachoeira do Chuvisco , 00°59’59”S 56°04’42”W, T. Giarrizzo, 30 Oct 2003.

Paratypes. All from rio Trombetas basin, Pará, Brazil : MPEG 23439, 248 mm SL, rio Trombetas , upstream of Cachoeira Porteira, 00°57’01”S 57°01’13”W, M. C. Andrade & T. Giarrizzo, 27 Feb 2011 ; MPEG 23440, 384 mm SL, rio Trombetas , Cachoeira Porteira, 01°03’47”S 57°02’31”W, T. Giarrizzo, 10 Nov 2003 ; MPEG 23441, 276 mm SL, rio Trombetas , Cachoeira Porteira, 01°03’47”S 57°02’31”W, T. Giarrizzo, 9 Nov 2003 ; MPEG 23442, 98 mm SL, rio Trombetas , Iteiro Grande , rapids of Traval, upstream of Cachoeira Porteira, 00°46’17”S 56°52’15”W, M. C. Andrade & D. A. Bastos, 25 Oct 2008 ; MPEG 23443 , 2 , 247-293 mm SL, rio Trombetas , upstream of Cachoeira Porteira, 00°55’07”S 57°01’36”W, M. C. Andrade & T. Giarrizzo, 24 Feb 2011 ; MPEG 23444 , 3 , 291-329 mm SL, rio Trombetas , upstream of Cachoeira Porteira, 00°55’07”S 57°01’36”W, M. C. Andrade & T. Giarrizzo, 27 Feb 2011 ; MPEG 23445, 127 mm SL, rio Trombetas , rapids of Enseada, 00°49’38”S 56°57’28”W, M. C. Andrade & D. A. Bastos, 24 Oct 2008 ; MPEG 23446 , 2 , 212 - 235.4 mm SL, rio Erepecuru , upstream of Cachoeira do Chuvisco, 00°59’59”S 56°04’42”W, T. Giarrizzo, 30 Oct 2003 ; INPA 2310, 167 mm SL, rio Cachorro , 2 km above confluence with rio Trombetas, E. G. Ferreira, 28 Nov 1987 ; INPA 2311, 180 mm SL, rio Mapuera , Cachoeira Patauá, 01°45’56”S 55°51’57”W, E. G. Ferreira, 27 Nov 1987 ; INPA 3639, 299 mm SL, rio Trombetas , Cachoeira Porteira above confluence with rio Cachorro, 00°59’21”S 57°04’09”W, E. G. Ferreira & M. Jégu, 15 Apr 1985 ; INPA 5173, 230 mm SL, rio Trombetas , downstream of Cachoeira Quebra Pote, E. F. Ferreira & M. Jégu, 9 Oct 1985 ; INPA 5176, 325 mm SL, rio Trombetas , near rio Caxipacoré, E. G. Ferreira & M. Jégu, 5 Oct 1985 ; MCP 47376 , 2 , 208-242 mm SL, rio Erepecuru , upstream of Cachoeira do Chuvisco, 00°59’59”S 56°04’42”W, T. Giarrizzo, 30 Oct 2003 ; MNRJ 40204 , 2 , 211-212 mm SL) rio Erepecuru , upstream of Cachoeira do Chuvisco, 00°59’59”S 56°04’42”W, T. Giarrizzo, 30 Oct 2003 ; MZUSP 15893 , 5 , 201-274 mm SL, rio Mapuera , Ilha da Facada, close to the confluence with the rio Trombetas, R. M. C. Castro, 21 Jul 1979 ; ZUEC 7066, 236 mm SL, rio Erepecuru , upstream of Cachoeira do Chuvisco, 00°59’59”S 56°04’42”W, T. Giarrizzo, 30 Oct 2003 ; ZUEC 7067, 291 mm SL, rio Trombetas , upstream of Cachoeira Porteira, 00°55’07”S 57°01’36”W, M. C. Andrade & T. Giarrizzo, 24 Feb 2011 .

Non-type specimens examined. All from Trombetas basin, Pará State, Brazil: MPEG 23449 , 910.8 mm SL, skel., Trombetas river , upstream of Cachoeira Porteira, 00°55’07”S 57°01’36”W, J. R. Carvalho Jr, 2 Dec 2007 ; MPEG 23448, 382 mm SL, skel., rio Trombetas , upstream of Cachoeira Porteira, 00°55’07”S 57°01’36”W, M. C. Andrade & T. Giarrizzo, 24 Feb 2011 ; MPEG 23452 , 2 , 355-382 mm SL, rio Trombetas , upstream of Cachoeira Porteira, 00°55’07”S 57°01’36”W, M. C. Andrade & T. Giarrizzo, 24 Feb 2011 ; MPEG 23451 , 2 , 175-322 mm SL, rio Mapuera , upstream of Cachoeira Porteira, 01°07’26”S 57°14’35”W, M. C. Andrade & D. A. Bastos, 26 Jun 2008 ; MPEG 23450 , 2 , 133-206 mm SL, rio Trombetas , Iteiro Grande , rapids of Traval, upstream of Cachoeira Porteira, 00°46’17”S 56°52’15”W, M. C. Andrade & D. A. Bastos, 25 Oct 2008 ; INPA 1238 , 43.94 mm SL, rio Mapuera , Cachoeira Porteira, E. G. Ferreira & M. Jégu, 10 Apr 1985 ; INPA 3637 , 44.74 mm SL, rio Trombetas , Cachoeira Porteira, 01°03’47”S 57°02’31”W, E. G. Ferreira & M. Jégu, 10 Apr 1985 .

Diagnosis. Tometes camunani is distinguished from its congeners by having neurocranium with a slight concavity at the level of the frontal bone (vs. concavity absent, dorsal profile of neurocranium straight). Tometes camunani is further distinguished among congeners by: five dentary teeth (vs. 6- 11 in T. makue , and 7-8 in T. lebaili ), 81-99 total scales in lateral-line (vs. 63-79 in T. trilobatus and 72-79 in T. lebaili ), and 37-42 scales around caudal peduncle (vs. 27-34 in T. trilobatus and 32-36 in T. lebaili ). Tometes camunani is also distinguished from T. trilobatus by having teeth with central cusp taller and acute (vs. central cusp shorter and with rounded edge). It also differs from T. lebaili by a relatively shorter distance from snout to pectoral-fin origin, 19.1-24.2% SL (vs. 24.5-30.4% SL), shorter head length, 21.4-25.9% SL (vs. 26.6- 29.8% SL), and by possessing a terminal to scarcely subterminal mouth (vs. upturned mouth). Tometes camunani is further distinguished from T. makue by having 12-26 prepelvic spines (vs. 0-9), 29-44 total spines (vs. 10-23), and by always possessing a pair of symphyseal dentary teeth, behind the main series (vs. symphyseal dentary teeth sometimes absent).

Description. Morphometric data is presented in Table 1. Body extremely compressed, overall aspect of body profile ovoid. Highest body depth at the level of the dorsal-fin origin. Dorsal head profile convex from mouth to vertical line through anterior portion of orbit, from latter point to supraoccipital base with a slight concavity (readily visible in radiography or skeletonized fish), supraoccipital spine straight to slightly convex, and approximately straight from supraoccipital tip to dorsal-fin origin. Dorsal-fin base scarcely convex; body profile straight from posterior end of dorsal-fin base to adipose-fin origin. Ventral profile of head and body (i.e., from lower lip to vertical through anterior portion of orbit and from the latter point to anal-fin origin) slightly convex. Caudal peduncle relatively short, profile of lower caudal peduncle slightly concave.

Snout broadly rounded. Mouth terminal to scarcely subterminal, jaws equally sized. Premaxillary teeth in labial row contacting teeth in lingual row. Five teeth in labial row, two teeth in lingual row ( Fig. 2c ). Premaxilary and dentary teeth incisiform, relatively robust and shorter when compared with the teeth of Ossubtus and Mylesinus , which are slender and taller. Premaxillary teeth 1-3 in labial row, each with sharp edge; teeth 1 and 2 separated by gap ( Fig. 2c,d ). Premaxillary teeth 4 and 5 in labial row shorter and broader than remaining teeth and with sigmoid edge ( Fig. 2c,d ). Dentary teeth 5, bito tricuspid, with the anterior cusp larger than posterior cusp; posterior cusp externally overlapping anterior cusp of the next tooth ( Fig. 2a ). Pair of symphyseal dentary teeth always present behind the main series of teeth. Maxillary edentulous.

Scales cycloid, numerous, diminutive and irregular in size, slightly larger in supracleithrum region and on caudal peduncle, decreasing in size toward flanks. Perforated lateral-line scales from supracleithrum to hypural plate 74-92 (90). Total perforated lateral-line scales 81-99 (96). Scale rows between dorsal-fin origin and lateral-line 51-68 (68). Scale rows between lateral-line and pelvic-fin insertion 52-75 (73). Circumpeduncular scales 37-42 (40). Ventral serrae reduced, with small prepelvic serrae weakly inserted on abdomen; prepelvic serrae 12-26 (22); simple postpelvic serrae 8-12 (12); double postpelvic serrae 5-8 (8); total serrae 29-44 (42).

Dorsal-fin origin at midbody, preceded by a strong, forward-directed spine. Distal margin of dorsal-fin falcate. Dorsal-fin rays ii-iii,20-22 (iii,21).Anal-fin rays iii-iv,31-34 (iii- 31). Pectoral-fin rays i,15-18 (i,17). Pelvic-fin rays i,7. Adipose fin present, with moderately long obliquely truncate distal margin. Caudal-fin forked, lobes similarly-sized.

Premaxillary lacking interdigitations at symphysis. Ascending premaxillary process elongated, moderately pointed and oblique in relation to antero-posterior axis of bone ( Fig. 2d,e ). Lateral premaxillary process short, subrectangular and protruding in relation to fifth tooth in labial row to one-third size of tooth ( Fig. 2c ). Lateral premaxillary process with a concavity where maxillary is inserted ( Fig. 2c ). Transversal process aligned with fifth tooth in labial series and protruding to one-fifth its size ( Fig. 2c ). Four replacement teeth trenches on premaxillary ( Fig. 2e ). Slender dentary, slightly arched, with 4 or 5 bony lamellae at symphysis ( Fig. 2a ). Antorbital club-shaped, wide anteriorly and lacking sensory canal. Supraorbital with serrated margins on inner and posterior portions. Infraorbitals 1, 5 and 6 with unbranched sensory canal, 2 and 3 with branched sensory canal, and 4 with canal shaped like an inverted Y.

Neurocranium high, triangular, and elongated. Mesethmoid elongated, pointed and triangular anteriorly. Ethmoidal wings elongated, slender antero-posteriorly, positioned on anterior half of mesethmoid. Neurocranium presenting a slight concavity at the level of the frontal. Parietal club-shaped, narrower anteriorly, increasing slightly in width posteriorly. Supraoccipital spine well developed, thin, dorsal portion slightly curved. Broad orbital region. Supraorbital with anteroventral margin slightly convex and posteroventral axis slightly downturned. Orbitosphenoid with two laterally compressed bony lamellae, anterior process widened distally and upturned. Orbitosphenoid posteroventral process narrow and projecting ventrally. Ventral margin of orbitosphenoid not reaching parasphenoid. Parasphenoid lacking midventral keel, and with a ventral aperture forming two thin projections parallel to each other across the ventral margins of the prootic and basioccipital. Pterotic triangular, with posterior process directed downward.Sphenotic thin with concave ventral margin; anterior portion wide, narrowing posteriorly from middle portion of bone ( Fig. 2b ).

First branchial arch with gill rakers elongated, stiff and recurved; 11-14 epibranchial gill rakers; ceratobranchial gill rakers 13-15; one gill raker at cartilage between ceratobranchial and epibranchial. Four branchiostegal rays; three branchiostegal rays on anterior ceratohyal and one on posterior ceratohyal. Total vertebrae 40-42 (41); predorsal vertebrae 10-11 (11); postdorsal vertebrae 14-16 (15). Vertebrae between verticals through last dorsal-fin pterygiophore and first anal-fin pterygiophore 2-3 (3). Supraneurals 6-8 (7).

The gut of T. camunani is long and elaborately coiled. The relative length of gastrointestinal tract (RLGIT=GITL/ SL) ranges between 4.2 and 5.5 times in SL (mean 4.9).

Color in alcohol. General coloration of body brownish-yellow, darker on dorsal portion. Dorsal, anal and caudal fins hyaline in proximal portion, darker towards margin. Caudal fin with a distal, wide, dark, diffuse band.Adipose fin uniformly brown. Pectoral and pelvic fins hyaline. Juvenile specimens up to 100 mm SL with a round dark blotch at the humeral region ( Fig. 3 ).

Color in life. Based on observations of freshly preserved specimens: general body color silver, dorsal and anal fins dark-brownish, caudal-fin with a distal, wide, dark band. During the reproductive period, irregularly-shaped red spots evident over flanks, in supracleithrum region and on the anal-fin, mainly in mature males.

Sexual dimorphism. Sexually mature males of Tometes (> 210 mm SL) are characterized by the presence of an additional anal-fin lobe ( Jégu et al., 2002c). In T. camunami , the second lobe is centered on branched anal-fin rays 14 to 16. The dorsal-fin rays of mature males of T. camunami are also elongated, forming filaments. Irregularly-shaped reddish blotches are present on the body in mature females, but are more conspicuous in mature males.

Based on the presence of the second anal-fin lobe, the smallest mature male of Tometes camunani observed measured 210 mm SL, which is similar to the size of the smallest recorded mature male of T. makue ( Jégu et al., 2002b) . In contrast, a second anal-fin lobe is only evident in specimens of Tometes trilobatus and T. lebaili at about 300 mm SL ( Jégu et al., 2002a,c). In some mature males of Tometes , the distal portions of the rays of the second anal-fin lobe have a pair of stiff, laterally curved hooks, which is similar to the condition observed in Mylesinus paraschomburgkii ( Jégu et al., 1989: fig. 8). Anal-fin rays with stiff hooks were observed in specimens of Tometes trilobatus , T. makue , and T. lebaili at about 400 mm SL ( Jégu et al., 2002a,b,c). Similarly-sized mature males of Tometes camunani (MPEG 23448, 382 mm SL;MPEG 23440,384 mm SL),however,lack stiff laterally curved hooks on second anal-fin lobe.

Distribution. Tometes camunani is known from the upper rio Trombetas and its tributaries rio Mapuera, rio Cachorro, and rio Erepecuru draining the Guiana Shield, Pará State, Brazil ( Figs. 4-5 ).

Etymology. Species refers to “camunani ”, its common name in the Wai-Wai language. The Wai-Wai inhabit the upper rio Trombetas basin, and consider the species of great cultural importance. The common name is also employed by local quilombolas (i.e., inhabitants of settlements founded by escaped slaves of African origin), who capture the fish using as bait the fruit of the camu-camu tree ( Myrciaria dubia , Myrtaceae ).

Ecological notes. The diet of the two smallest specimens examined (MPEG 23449 and MPEG 23450; 90.8 and 133 mm SL, respectively) was composed mainly of fragments of Podostemaceae and benthic macroinvertebrates ( Leptophlebiidae , Simuliidae and Chironomidae ). The largest specimens examined (MPEG 23448; MPEG 23450; MPEG 23451; MPEG 23452; n = 6, 175-382 mm SL) consumed mainly leaves of Podostemaceae , and fragments of grass and whole seeds of Myrtaceae and Fabaceae . Oxyuroid nematodes (Rondonia rondoni) were also found in the gastrointestinal tract of all dissected specimens.

Figures

Fig. 1. Tometes camunani, MPEG 23447, holotype, mature male, 224.3 mm SL; Brazil, Pará, Oriximiná, Trombetas basin, rio Erepecuru, upstream of Cachoeira do Chuvisco.

Fig. 2. Tometes camunani, MPEG 23448, 382 mm SL. a, lingual view of left dentary. b, lateral view of the neurocranium. c-e, ventral, labial and lingual views of the left premaxilla (1-5: teeth in labial row; 1’-2’: teeth in lingual row). ap = ascending process of premaxilla; bas = basioccipital; fr = frontal; let = lateral ethmoid wing; lm = lamellae at symphysis; lp = lateral process of premaxilla; mt = mesethmoid; nc = neural complex; oph = orbitosphenoid; pa = parietal; pas = parasphenoid; pro = prootic; ptc = pterotic; su = supraoccipital; so = supraorbital; sph = sphenotic; sy = position of symphyseal tooth; tp = transversal process; tr = replacement teeth trenches. Scale bar: 10 mm.

Fig. 3. Tometes camunani, INPA 3637, juvenile, 44.7 mm SL; Brazil, Pará, Oriximiná, rio Trombetas, Cachoeira Porteira.

Fig. 4. Map of upper rio Trombetas basin and adjoining areas, showing the distribution of Tometes camunani. Star indicates type locality.

Fig. 5. Typical habitat of Tometes camunani, rapids and waterfalls in rio Trombetas basin, Pará, Brazil. Rocks are covered with Podostemaceae, rheophilic aquatic plants typical of the diet of species of Tometes (Photo by D. Bastos, 2008).