Aequidens pirilampo, Oliveira & Tencatt & Deprá & Britzke & Oliveira & Graça, 2024
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publication ID |
https://doi.org/ 10.1590/1982-0224-2023-0106 |
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publication LSID |
lsid:zoobank.org:pub:970EB7E6-5A64-4A03-AEE3-81A4FB2D0E9F |
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persistent identifier |
https://treatment.plazi.org/id/D24B87C2-E815-FFB7-3031-586215BE8965 |
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treatment provided by |
Felipe |
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scientific name |
Aequidens pirilampo |
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sp. nov. |
Aequidens pirilampo , new species urn:lsid:zoobank.org:act:6F182F43-5BFE-46B4-B7DE-6580FE19C11F
( Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 ; Tab. 1)
Aequidens. — Melo et al., 2022: 332 (Brazil, Mato Grosso, Ribeirão Comprido; first record).
Aequidens sp. — Gimênes, Rech, 2022: 595 (Brazil, Mato Grosso, photo).
Holotype. NUP 23543, 94.7 mm SL, Brazil, Mato Grosso State, Itiquira Municipality, ribeirão Comprido, tributary of the rio Correntes, rio Paraguai basin, 17º32’04”S 54º25’36”W, 27 Jan 2021, L. F. C. Tencatt & M. N. Souza.
Paratypes. All from Brazil, rio Paraguai basin. Mato Grosso State: Itiquira Municipality: LBP 30742, 1, 42.1 mm SL, 18 Sep 2021, L. F. C. Tencatt, M. N. Souza & M. A. Alves; LBP 30743, 1, 48.3 mm SL, 5 Apr 2018, L. F. C. Tencatt, M. N. Souza & M. A. Alves; LBP 31524, 4, 41.8 – 94.0 mm SL, 18 – 21 Sep 2021, L. F. C. Tencatt, M. N. Souza & M. A. Alves, same data as holotype. MCP 54880, 4, 42.6 – 67.0 mm SL, MZUEL 22500, 4, 43.0 – 76.6 mm SL, NUP 23546, 5, 39.8 – 66.2 mm SL, NUP 23547, 2 c&s, 59.2 – 59.6 mm SL, collected with LBP 31524. NUP 21644, 9, 28.7 – 68.5 mm SL, córrego de Cima, tributary of the rio Correntes, 17°39’52”S 54°14’46”W, 31 Aug 2018, Nupélia staff. NUP 23544, 7, 14.9–87.2 mm SL, collected with holotype. Mato Grosso do Sul State: Sonora Municipality: CITL 392, 10, 24.5 – 74.5 mm SL, córrego de Baixo, tributary of the rio Correntes, 17º42’33”S 54º21’32”W, 7 Aug 2021, L. F. C. Tencatt, M. N. Souza, V. Carvalho & M. A. Alves. CITL 393, 4, 17.3 – 39.3 mm SL, unnamed stream, tributary of the rio Correntes, 17º35’42”S 53º53’33”W, 29 Dec 2020, L. F. C. Tencatt & M. N. Souza. CPUFMT 7763, 2, 64.8 – 66.1 mm SL, same data as CITL 392, 2 Oct 2021, L. F. C. Tencatt, M. N. Souza & M. A. Alves.
Diagnosis. Aequidens pirilampo is distinguished from all congeners, except A. plagiozonatus , by having anteriorly oblique dark brown flank bars (vs. vertical). The new species differs from A. plagiozonatus by having the dorsal head contour, from the tip of the snout to the vertical through the posterior margin of the eye, almost straight, except for a conspicuous concavity at the interorbital region ( Fig. 2 View FIGURE 2 ) (vs. dorsal head contour convex, with a subtle concavity at the interorbital region in occasional specimens), by having longer lower jaw (40.2–46.9% HL and 16.7–18.5% SL vs. 35.2–39.3% HL and 13.2–15.2% SL in A. plagiozonatus ), and longer upper jaw, (12.2–15.1% SL vs. 9.3–12.1% SL in A. plagiozonatus ). Additionally, A. pirilampo is distinguished from its congeners, except A. chimantanus Inger, 1956 , A. diadema , A. epae , A. mauesanus Kullander, 1997 , A. michaeli , A. patricki Kullander, 1984 , A. plagiozonatus , A. potaroensis Eigenmann, 1912 , and A. tubicen Kullander & Ferreira, 1991 , by having a discontinuous lateral band in fixed specimens (vs. continuous). Aequidens pirilampo differs from A. diadema and A. epae by having the lateral band divided into blotches more conspicuous at the encounter with flank bars (vs. lateral band not divided into blotches), and by the absence of unpigmented areas anteriorly and posteriorly to the midlateral spot, not forming a whitish circle above the longitudinal stripe (vs. presence). Aequidens pirilampo , also differs from A. epae by having the dorsal portion of the flank bar 5 anteriorly inclined and less conspicuous than the midlateral spot (vs. posteriorly inclined and as dark as the midlateral spot). Aequidens pirilampo also differs from A. rondoni (Miranda Ribeiro, 1918) by having eight flank bars (1a, 1p, 2, 3, 4, 5, 6, and 7; Fig. 4 View FIGURE 4 ) instead of nine (1a, 1p, 2 bars, 3 – 4 expressed as three bars, 5, 6, and 7). Aequidens pirilampo differs from A. mauseanus , A. michaeli and A. potaroensis by having the lateral band equally conspicuous along its entire length (vs. lateral band more inconspicuous anterior to midlateral spot in A. mauseanus and A. potaroensis , and posterior to midlateral spot in A. michaeli ); from A. mauseanus by the absence of a dark-brown blotch dorsal to midlateral spot (vs. presence); from A. michaeli by having a cheek spot (vs. absence), and by the absence of iridescent vermiculations on the cheek, opercle and pectoral girdle (vs. more ornamented pattern with stripes present in the cheek, opercle and pectoral girdle); from A. paloemeuensis Kullander & Nijssen, 1989 and A. potaroensis by the suborbital stripe not retained in adult specimens (vs. retained). Aequidens pirilampo differs from A. patricki by the absence of large, dark-brown blotches on the cheek and opercle (vs. presence), and by the brown lachrymal region (vs. unpigmented). Aequidens pirilampo differs from A. tubicen by the absence of a preopercular spot (vs. presence). Additionally, Aequidens pirilampo differs from A. gerciliae by the round midlateral spot (vs. longitudinally elongated); from A. metae Eigenmann, 1922 by the cheek spot not spanning the entire anterior margin of the vertical arm of the preopercle (vs. spanning the entire anterior margin of the vertical arm of the preopercle); from A. superomaculatum Hernández-Acevedo, Machado-Allison & Lasso, 2015 by the absence of a posterodorsal blotch on the flank (vs. presence).
Description. Based on holotype and paratypes. Measurements in Tab. 1. See also Figs. 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 for details of shape and color pattern. Body laterally compressed. Predorsal contour ascending straight from tip of snout to vertical through posterior margin of orbit. Moderately convex from this point to end of dorsal fin; straight along caudal peduncle. Prepelvic contour descending straight or slightly convex from tip of snout to vertical through posterior margin of preopercle, at same angle of predorsal contour (young specimens have more obtusely angled predorsal contour than prepelvic). Abdominal contour straight or slightly convex and horizontal. Anal-fin base contours straight and oblique. Caudal peduncle ventral contour straight or slightly concave and horizontal.
Head elongate, triangular in lateral view, with dorsal margin, from tip of snout to end of supraoccipital, ascending straight and oblique, ventral contour less steep than dorsal contour. Groove between eyes. Snout long, with frontal contour elongated and continuous with dorsal and ventral contour of head. Lips thick and of “American type ”, i.e., lower lip fold covers upper lip. Tip of maxilla almost reaching vertical through anterior margin of eye. Nostril dorsolaterally situated, below horizontal through lower margin of orbit, halfway between tip of snout and orbit (in young specimens, closer to eye, horizontal through middle of eye). Orbit large, situated on dorsal half of head, pupil ventral to level of upper lateral line. Posterior margin of preopercle, opercle, subopercle, interopercle and suprachleitrum smooth, without serrations.
E1 scales 24(18), 25*(14) or 26(1). Scales between upper lateral line and dorsal-fin 3* (24), 3½ (9) at base of first dorsal-fin spine, 1½(27), 2*(5), 2½(2) at base of last dorsal-fin spine. Scale rows between lateral line 2*(27). Scales on lateral line 13/8(1), 14/8(1), 15/7(2), 15/8(2), 16/6*(2), 16/7(5), 16/8(5), 17/6(1), 17/7(2), 17/8(5); additionally 1(4), 2*(23) or rarely 3(1) scales of lower lateral line onto caudal fin. Cheek scales in 3*(9), 3½(10), or 4(10) rows, ctenoid. Opercle scales 4(1), 5(2) or 6*(23), large and cycloid, stochastically arranged. Subopercle covered with 3*(32) cycloid scales. Interopercle with 2(15), 3*(14) or 4(2) scales embedded in skin. Scales absent from preopercle. Infraorbital scales 5(3), 6*(25) or 7(4). Circumpeduncular scale rows 16*(35), including lateral line scales. Predorsal scales uniserial(2), biserisal(2), triserial*(24) or stochastic(1), cycloid, slightly smaller than flank scales. Flank scales ctenoid. Prepelvic scales 6(1), 7(3), 8(4), 9(1), 10*(12), 11(7), 13(1), ctenoid, same size towards gular region. Abdominal scales ctenoid, slightly smaller than flank scales. Pectoral, pelvic, dorsal, and anal fins without scales. Caudal-fin base covered with stochastically distributed transition scales, intermediate in size between peduncular and inter-radial scales; caudal fin with cycloid inter-radial scales from base of rays to ⅓ of its length; series increasing ontogenetically, 2–5 scales in specimens up to 40 mm covering from basal ⅛ to basal ⅙, 4–14 scales in specimens over than 40 mm SL, covering from basal ¼ to basal ⅓, without secondary series; one specimen (NUP 21644, 68.5 mm SL) with series of scales with pores and canals between rays D3–D4 (8 scales) and V3–V4 (8 scales).
Paratypes
Holotype
N Range Mean SD Standard length (mm) 94.7 26 40.1–94.0 60.0 – Percents of standard length
Body depth 43.7 26 41.9–46.6 44.2 1.4 Preanal distance 74.1 26 72.8–79.4 76.4 1.6 Prepelvic distance 45.5 26 43.9–48.5 46.4 1.1 Prepectoral distance 39.9 26 37.7–44.4 41.3 1.6 Predorsal distance 43.4 26 42.6–48.8 46.0 1.7 Distance from dorsal to caudal fin 70.2 26 63.9–68.8 66.2 1.2 Distance from dorsal to anal fin 56.6 26 52.9–57.6 55.5 1.2 Distance from dorsal to pelvic fin 42.8 26 42.2–46.6 43.9 1.2 Distance from dorsal to pectoral fin 26.5 26 26.5–31.4 28.4 1.2 Caudal peduncle depth 16.9 26 15.5–17.6 16.7 0.5 Caudal peduncle length (straight) 7.7 26 4.9–8.0 6.0 0.7 Caudal peduncle length (oblique) 12.0 26 10.2–12.3 11.0 0.5 Pectoral-fin length 30.6 25 28.5–33.6 31.0 1.4 Pelvic-fin length 32.8 26 28.1–39.6 32.2 2.7 Pelvic spine length 12.2 26 11.9–15.7 13.5 1.0 Dorsal-fin base length (spine) 42.1 26 40.3–46.9 42.8 1.6 Dorsal-fin base length (total) 61.3 26 54.6–61.4 58.6 1.6 Last dorsal-fin spine length 11.8 26 11.5–15.1 13.0 1.0 Anal-fin base length (spine) 5.2 26 4.2–6.5 5.3 0.5 Anal-fin base length (total) 19.5 26 16.7–19.6 18.2 0.8 Last anal-fin spine length 12.9 26 11.4–15.6 12.9 0.9 Head length 39.1 26 37.8–43.0 40.5 1.3 Head depth 38.9 26 34.7–39.9 37.1 1.7 Head width 18.7 26 17.6–20.9 19.3 0.9 Orbital diameter 9.0 26 10.5–15.0 12.7 1.3 Postorbital head length 14.9 26 14.4–15.5 14.9 0.3 Interorbital distance 13.1 26 9.2–19.2 11.0 1.8 Snout length 15.7 26 11.6–15.2 13.7 0.9 Cheek depth 11.0 26 8.7–11.8 10.5 0.8 Lachrymal depth 8.2 26 5.0–7.8 6.7 0.8 Upper jaw length 14.2 26 12.2–15.1 13.6 0.8 Lower jaw length 17.5 26 16.8–19.2 17.9 0.6 Midlateral spot length 9.4 26 7.9–10.7 9.5 0.7 Percents of head length
Head depth 99.5 26 69.8–100.5 91.5 4.8 Head width 47.8 26 45.2–51.1 47.6 1.7 Orbital width 23.0 26 23.0–36.5 31.4 2.6 Postorbital 38.1 26 35.3–39.2 36.8 0.9 Interorbital width 33.4 26 23.0–46.6 27.2 4.5 Snout length 40.2 26 24.9–40.2 33.7 2.2 Cheek depth 28.2 26 21.4–31.1 25.9 2.3 Lacrimal depth 20.9 26 12.4–20.9 16.5 2.3 Upper jaw length 36.3 26 29.7–38.0 33.6 2.3 Lower jaw length 44.7 26 40.2–46.9 44.1 1.6
Dorsal-fin rays XIV.10(1), XIV.11(3), XV.9(2), XV.10(19), XV.11*(7); dorsal spines increasing in size up to 6 th, first spine about one-fourth length of last. Dorsal-fin rays 4–5 forming filament reaching over ⅔ of caudal fin length in some specimens; lappets rounded to pointed, with posterior margin free, slightly surpassing tip of spines. Anal-fin rays III.7.i(3), III.8(4), III.8.i(19), III.8.ii(2), III.9*(4) or IV.9(1); middle rays longest, pointed, in some specimens forming filament reaching up to half of caudal-fin length. Caudal-fin rounded, with 14*(32) principal rays. Total pectoral-fin rays 12(2), 13(13), 14*(18) or 15(1). Pectoral fin ventrally rounded, dorsally pointed, fourth ray longest, in some specimens passing posterior margin of midlateral spot. Pelvic-fin rays I.5*(34); second ray longest, with filamentous extension, reaching or passing anal-fin origin.
Gill rakers externally on first epibranchial 1(10) or 2*(24); 0(2) or 1*(32) on angle; 4(8), 5*(20), 6(3) or 7(1) on ceratobranchial 1.
Teeth unicuspid, decreasing gradually from symphysis. Symphysis of both jaws lacking teeth. Upper jaw series with 3–4 rows; lower jaw series with 2–4 rows. External hemiseries of upper jaw right/left sides with 9–13/ 11–12 in specimens up to 40 mm; 10–22/ 6–23 in specimens over 40 mm. External hemiseries of lower jaw right/left sides with 16–21/ 17–21 in specimens up to 40 mm; 17–25/ 11–26 in specimens over 40 mm.
Suture between contralateral ceratobranchial 5 not including interdigitations ventrally; posteromedial teeth large, cylindrical, with large, blunt, dorsally oriented cusp and 1–2 very small, anteriorly oriented cusps; anterolaterally, teeth gradually diminishing in size; outer teeth compressed transversally, with large cusp and 1–2 very small, upward cusps. Lower pharyngeal jaw tooth-plate (ceratobranchial 5) ( Fig. 5 View FIGURE 5 ) length including posterolateral processes 89.9% of width; length of dentigerous area 59.8% of width; 13 teeth along posterior margin each side; seven teeth along symphyseal margin; 22 teeth along outer margin. Pharyngobranchial 2 with seven teeth arranged in two rows, posteriormost ones larger, turned anteriad. Pharyngobranchial 3 with 34 teeth arranged in 6 rows turned backwards. Tooth plate 4 with 51 teeth arranged in 7 rows turned posteriad; three concavities in the frayed zone at the posterior margin. Ceratobranchial 4 with 2 tooth plates, posterior with 5–6 teeth, anterior with 6–9 teeth. Two supraneurals, anterior to first neural spine. Twenty-seven total vertebrae, of which 13(2) abdominal (4 and 5 type A’, others type A) and 13(2) caudal (first 12 type and PU 1+U1). Three posteriormost vertebrae ( CV 3, CV 2 and PU 1+U1) completely included in the caudal peduncle. Ribs 10, abdominal. Vertebrae bearing ribs, 3rd–12th. Epineurals absent. Twenty-four dorsal-fin pterygiophores (one spine or ray for each pterygiophore), surrounded by vertebrae 1–20. Ten anal-fin proximal pterygiophores (first one bearing first two spines; last one bearing last two rays), surrounded by vertebrae 13–20 (anteriormost pterygiophore touches the anterior margin of haemal spine of 14th vertebra). Two epurals. One uroneural. Five branchiostegal rays. First branchial arch with 7 outer rakers (one on epibranchial, one on angle, and five on ceratobranchial) and 11 inner rakers (2 on epibranchial, one on angle, and 8 on ceratobranchial). Second arch with 12 external rakers (two on epibranchial, one between epibranchial and ceratobranchial, eight on ceratobranchial, and one between ceratobranchial and hypobranchial) and 8 inner rakers (on ceratobranchial). Third arch with 11 external rakers (one on epibranchial, one between epibranchial and ceratobranchial, and nine on ceratobranchial) and 11 inner rakers (one on epibranchial, two between epibranchial and ceratobranchial, and eight on ceratobranchial). Fourth arch with 11 external rakers (one on epibranchial one between epibranchial and ceratobranchial, and nine on ceratobranchial) and 10 inner rakers (epibranchial lacking rakers, all on ceratobranchial). Two procurrent caudal-fin rays dorsally and three ventrally. Microbranchiospines on all four branchial arches.
Coloration in alcohol. Background light beige to yellowish brown; ventral region yellowish white; dorsal region dark brown. Posterior margin of flank scales with diffuse brown pigmentation. Head brownish on neurocranial region and nape; yellowishbrown on cheek, preopercle and opercle region; and yellowish white ventrally. Cheek spot dark brown. Three oblique, beige stripes continuous across dorsal midline of head. First along anterodorsal margin of lachrymal, from tip of snout to anterior margin of orbit, through nostril. Second from near anteroventral margin of lachrymal to anteroventral margin of orbit. Third along posteroventral margin of lachrymal and infraorbitals. Stripes absent from cheek, gill cover and pectoral girdle. Nine bars along body being eight bars on flank and one (bar 9) on head ( Figs. 4A, B View FIGURE 4 ): bar 1p, at caudal-fin base, forming blotch; bar 1a, on distal portion of caudal peduncle; bar 2, at vertical through last soft dorsal- and anal-fin rays; bar 3, at vertical through first soft dorsal- and anal-fin rays; bar 4, at vertical through last dorsal-fin spine and anal-fin spines; bar 5, usually at vertical through 8 th –11 th dorsal-fin spines and vent; bar 6, usually at vertical through 4 th –8 th dorsal-fin spines and posterior to pelvic-fin base; bar 7, usually at vertical through base of first dorsal-fin spines to pectoral-fin origin; bar 8, on nape and, more diffusely, on opercle; bar 9, formed by supraorbital and infraorbital bars, the latter present only in young specimens ( Figs. 4C–F View FIGURE 4 ). Lateral band dark brown, divided into blotches at intersections with flank bars, mainly concentrated along E1 scale series. Midlateral spot on bar 5, covering E1 and E2 series. Beige to brown fins. Dorsal fin lighter on distal margin; small, rounded white blotches on soft portion, in occasional specimens forming oblique stripes. Anal fin with same pattern as dorsal fin. Caudal fin lighter on distal margin; small white blotches more concentrated on anterior two thirds, forming dotted or striped pattern (better viewed in fixed and smaller specimens) ( Fig. 4 View FIGURE 4 ); one black blotch, usually ocellated, corresponding to bar 1p, at base of all rays of dorsal lobe.
Coloration in life. Based on Fig. 3 View FIGURE 3 and field observations by LFCT (2018–2021). Background pale to light beige; ventral region whitish. Head brownish in dorsal region, with silvery scales on nape; lachrymal and cheek silvery, border of the scales yellow to brownish, with black cheek spot posteroventral to orbit, between third oblique stripe below lacrimal and preopercle upper portion; preopercle and interopercle silvery, subopercle light beige; opercle light brownish, border of the scales yellow to silvery brownish; middorsal portion typically with brownish orange patch; ventral region light beige. Body covered by green, yellow, and blue iridescent coloration. Scales on flank silvery, forming a more evident reticulated pattern, with brownish borders at posterior margin. Pattern of dark blotches, stripes, and bars less evident than in preserved specimens, but similar in relation to number and position of color-pattern elements. Fins yellowish. Dorsal fin with white blotches at membranous region between spines/ rays, with distal portion yellow. Anal fin with distal portion yellow, blotches as same pattern as preserved specimens. Pelvic fin yellowish at first spine and rays region, proximal region light beige, distal region yellowish. Caudal fin yellowish, base with blue iridescent spots/stripes.
Geographical distribution. Aequidens pirilampo is currently only known from tributaries of the upper rio Correntes, a tributary of the rio Paraguai basin, in the border region between Mato Grosso and Mato Grosso do Sul states, Brazil ( Fig. 6 View FIGURE 6 ).
Ecological notes. General view on the collecting sites of Aequidens pirilampo in Fig. View FIGURE 7 7. The new species lives in lentic mesohabitats with depths ranging from around 10 cm (particularly hatchlings) to slightly over 1 m with a lot of submerged vegetation (macrophytes in general, including those floating in some points). Unlike other Aequidens species, which are usually found in brownish water (tea-colored water) environments, the upper rio Correntes and its tributaries present extremely crystalline water except for environments degraded by anthropic impacts, allowing the observation of solitary fish foraging close to submerged vegetation during the day. The species is found in syntopy with Astyanax sp. , Characidium chicoi , Characidium aff. zebra Eigenmann, 1909 , Cnesterodon cf. septentrionalis Rosa & Costa, 1993, Cyphocharax caboclo , Eigenmannia correntes , Hyphessobrycon sp. , Hypostomus sp. , Melanorivulus cf. dapazi (Costa, 2005), and Moenkhausia lopesi Britski & Silimon, 2001 . The subterranean stretch (or the sinkhole itself) of the rio Correntes is hypothesized to be a barrier to the fish fauna of the basin. However, Aequidens pirilampo , as well as the other four endemic species described from the upper rio Correntes basin, were not found in all sampling sites upstream the sinkhole during the four years of survey efforts in the region. In the Ponte de Pedra hydroelectric power station Reservoir (just upstream of the sinkhole), none of these endemic species was captured. At this site, only A. plagiozonatus was found ( Fig. 8A View FIGURE 8 ), along with several other species common to most tributaries of the upper rio Paraguai basin (e.g., Saxatilia lepidota (Heckel, 1840), Hyphessobrycon herbertaxelrodi Géry, 1961 , Megalechis thoracata (Valenciennes, 1840) , Metynnis cf. maculatus (Kner, 1858) , and Satanoperca pappaterra (Heckel, 1840) , including some introduced species like Cichla spp. and Colossoma sp. (the last one not captured, with occurrence confirmed by several locals). Considering the currently available data, it seems that a large waterfall (estimated to be at least 50 m high; 17°32’06”S 54°26’01”W) in the area of a small hydroelectric power plant represents the downstream limit of occurrence of the new species. Aequidens pirilampo is the only cichlid known to occur upstream at this point. None of the aforementioned species, except for the new species, was captured upstream of this waterfall.
Etymology. The specific epithet “ pirilampo ” means firefly in the popular Portuguese naming in the region the new species occurs. It is a bioluminescent Coleoptera very common in this region. These insects emit an intense green light, which alludes to the color pattern in life displayed by the new species. A noun in apposition.
Conservation status. The new species is currently known from two tributaries of the upper rio Correntes basin, which is severely impacted due to intense agricultural activity (see Melo et al., 2022) causing a decrease in riparian plant cover and, as a result, a silting process. Additionally, the region has been impacted by the installation of hydroelectric power plants, and further hydroelectric projects are already planned (see ANA, 2019). The Extent of Occurrence (EOO) of Aequidens pirilampo was estimated at about 200 km 2. Therefore, considering the relatively restricted geographic distribution of the new species and the severe anthropic impacts in the region, and according to the International Union for Conservation of Nature (IUCN) categories and criteria (IUCN, 2022), Aequidens pirilampo is herein suggested to be classified as Near Threatened (NT), approximating the Endangered (EN) category by criterion B1b(iii).
Common name. Aequidens pirilampo is popularly known as ‘cará’.
Molecular analysis. The final matrix of Aequidens species comprises 25 terminal taxa (including 23 species of Aequidens ) and 402 characters, being 303 conserved and 99 variable sites (of which 96 were parsimony-informative), with 22.8% adenine, 28.7% cytosine, 31.7% thymine and 16.8% guanine (% in relation to the entire alignment).
The estimated index of substitution saturation (Iss) performed in DAMBE 5.2.31 (Xia, Xie, 2001) showed that the data was not saturated (i. e., Iss.c value greater than Iss). Genetic distances (Kimura, 1980) of the COI gene between Aequidens pirilampo and other Aequidens and Cichlasoma species are presented in Tab. 2. All species delimitation analyses corroborate the separation of A. pirilampo from the other Aequidens and Cichlasoma species included in this study ( Fig. 9 View FIGURE 9 ).
The ML tree inferred through MEGA-X recovered the two groups consistent with the genetic distance analysis and the previous morphological identification of species and exhibited strong node support for each species, i.e., 100% for the A. pirilampo clade and 99% for A. plagiozonatus clade ( Fig. 9 View FIGURE 9 ) (see Figs. S2 View FIGURE 2 , S 3 View FIGURE 3 , S 4 View FIGURE 4 , S 5 View FIGURE 5 ) for details in the delimitation analyses). The ABGD analysis resulted in eight partitions that ranged from
96 (P = 0.036) to 169 (P = 0.00113) lineages, with three partitions (P = 0.0031 –0.00821)
resulting in 15 lineages, and the ASAP analysis resulted in 10 partitions that ranged from
7 (score = 5.5) to 21 (10.5) lineages, with one partition with 16 lineages (lowest score
= 3.0) ( Fig. 9 View FIGURE 9 ). All species delimitation analyses support the presence of two species of
Aequidens occurring in the rio Paraguai basin, the first, A. pirilampo , described herein,
and the second, A. plagiozonatus occurring in both the rio Paraguai and Araguaia basins,
however, PTP analysis recovered several lineages within A. plagiozonatus .
Material comparative examined. Brazil, rio Amazonas basin: Aequidens gerciliae : NUP 7200, 3, 52.7– 59.1 mm SL. NUP 7483, 1, 46.7 mm SL. NUP 18442, 1, 82.4 mm SL. Aequidens pallidus : NUP 17281, 83.0 mm SL. Aequidens tetramerus : INPA 972, 84.7 mm SL. NUP 17983, 6, 34.9–140.9 mm SL. NUP 19382, 1, 76.9 mm SL. Rio Araguaia basin: Aequidens plagiozonatus : LBP 30741, 1, 39.2 mm SL. Rio Paraguai basin: Aequidens plagiozonatus : LBP 1912, 5, 43.9–61.8 mm SL. LBP, 1925, 3, 40.7–54.0 mm SL. LBP 10767, 3, 41.1–56.7 mm SL. NUP 194, 3, 77.0– 88.8 mm SL. NUP 13372, 3 (2 c&s), 57.1–76.6 mm SL. NUP 21604, 3, 37.4–52.0 mm SL. NUP 21621, 3, 25.4–48.2 mm SL. NUP 21368, 1, 81.4 mm SL. Rio Tapajós basin: Aequidens rondoni : MNRJ 1616, photograph and x-ray of the holotype of Acaropsis rondoni . Guyana, rio Potaro: Aequidens potaroensis : FMNH 53892, photograph of the holotype, 140 mm SL. Venezuela, rio Orinoco basin: Aequidens chimantanus : FMNH 45702, photograph of the holotype.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.