Eigenmannia waiwai, Peixoto & Dutra & Wosiacki, 2015

Peixoto, Luiz Antônio Wanderley, Dutra, Guilherme Moreira & Wosiacki, Wolmar Benjamin, 2015, The Electric Glass Knifefishes of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species, Zoological Journal of the Linnean Society 175 (2), pp. 384-414 : 408-410

EIGENMANNIA VICENTESPELAEA TRIQUES, 1996

( FIGS 5A , 21 , 22 ; TABLE 4)

Eigenmannia vicentespelaea Triques, 1996: 3 (original description; type locality, State of Goiás, Rio Tocantins basin, Rio São Vicente, Cave São Vicente II, Brazil). Romero & Paulson, 2001: 29 (cheklist). – Albert, 2003: 488 (catalogue). Bichuette & Trajano, 2006: 101 (comments on morphology, distribution, and expand- ed diagnosis).

Diagnosis: Eigenmannia vicentespelaea can be distinguished from others species in the E. trilineata species group, except E. waiwai , by the subterminal mouth (versus terminal mouth). Eigenmannia vicentespelaea also differs from species in the E. trilineata species group, except E. microstoma , by the length of the coronomeckelian bone equal to 45% of the length of Meckel’s cartilage ( Fig. 5 ; versus 20% of the length of Meckel’s cartilage). Eigenmannia vicentespelaea can be distinguished from E. microstoma and E. waiwai by the body depth at the vertical through the longest pectoralfin ray, 10.5–14.5% LEA (versus 16.9–20.8% and 14.9– 18.7%, respectively); seven or eight longitudinal series of scales above the lateral line (versus 11–15 and nine or ten, respectively); and length of anterodorsal process of the maxilla equal to 50% of the width of the posterior nostril (versus equal to the width of the posterior nostril in E. microstoma and 1.5 times the width of the posterior nostril in E. waiwai ). Eigenmannia vicentespelaea also differs from E. microstoma by the body depth at the vertical through the first anal-fin ray, 11.5–13.3% LEA (versus 14.0–18.1%); head depth at the posterior limit of the supraoccipital, 68.6– 74.7% HL (versus 76.1–101.1%); suborbital depth, 21.7– 27.4% HL (versus 29.9–40.8%); and head depth at the orbit, 49.3–55.8% HL (versus 56.7–78.1%). Eigenmannia vicentespelaea can be further distinguished from E. waiwai by the depth of posterodorsal expansion on infraorbitals 1 + 2 approximately equal to the total length of infraorbitals 1 + 2 (versus less than 50% of the length of infraorbitals 1 + 2).

Description: Morphometric data are presented in Table 4. Body elongate and laterally compressed. Dorsal profile of body nearly straight from rear of head to vertical through middle of anal fin, and then posteroventrally aligned with distal portion of caudal filament. Ventral profile of body slightly concave along anterior half of abdominal cavity, then posterodorsally aligned with the last anal-fin ray. Ventral margin of caudal filament straight. Greatest body depth at vertical through distal margin of pectoral fin.

Head laterally compressed with greatest width at opercular region and greatest depth at posterior margin of supraoccipital. Dorsal profile of head slightly convex from upper lip to vertical through branchial opening. Ventral profile of head slightly concave from anterior margin of lower lip to branchial opening. Snout rounded in profile. Mouth subterminal. Upper lip overlapping lower lip. Premaxillary teeth 25(1) or 26(2), distributed in four rows [outermost row with 5(1) or 6(2) teeth; second row with 4(1) or 7(2) teeth; third row with 7(2) or 8(1) teeth; innermost row with 5(1), 6(1), or 9(1) teeth]. Maxilla with sickle-shaped anterodorsal process equal to 50% width of posterior nostril. Dentary teeth 38(1), 41(1), or 45(1) distributed in three or four rows [outermost row with 12(1), 15(1), or 21(1) teeth; second row with 14(2) or 16(1) teeth; third row with 10(1) teeth; innermost row with 2(1) or 10(2) teeth]. Dentary teeth all similar in size. Coronomeckelian bone equal to 45% of length of Meckel’s cartilage. Endopterygoid with 10(1), 12(1), or 15(1) teeth in two rows. Mouth rictus at vertical through anterior nostril or in region between nares. Anterior naris tube-like, posterior margin located at vertical through posterior margin of, or in median portion of, rictus. Posterior naris elliptical, without tube, located closer to anterior margin of eye than snout tip. Eye approximately circular; of different stages of development ranging from completely absent to fully developed, with no apparent link to ontogenetic development. When present, covered by skin, laterally located on anterior half of head. Antorbital and infraorbitals 1–4 in form of enlarged, partial cylinders with slender osseous arches. Fifth and sixth infraorbitals slender and tubular. Depth of posterodorsal expansion on infraorbitals 1 + 2 approximately equal to total length of infraorbitals 1 + 2. Branchial opening moderately elongate. Branchial membrane joined to isthmus. Anus and urogenital papilla shifting anteriorly ontogenetically; at vertical through posterior margin of orbit in mature specimens.

Cycloid scales present from immediately posterior to head to distal portion of caudal filament. Lateral line complete, with 110(1), 117(1), 119(1), 121*(1) 122(2), 123(2), or 125(2) perforated scales to vertical through end of anal fin. Longitudinal series of scales above lateral line 7*(3) or 8(7). Scales over anal-fin pterygiophores approximately one-half the size of others.

Pectoral-fin rays, ii,15*(4), ii,16 (5), or ii,17(1). Distal margin of fin approximately straight. Tip of pectoral fin reaching vertical throught base of anal-fin rays 15– 19. Anal fin origin immediately posterior to vertical through pectoral-fin base. Total anal-fin rays, 169– 191* (most specimens with anal fin damage, including holotype, N = 10; Table 2). Distal margin of anal fin approximately concave. Caudal filament cylindrical, tapering gradually distally, relatively short and approximately 30% of LEA in sexually mature specimens.

Precaudal vertebrae, 13(1) or 14(2). Anterior vertebrae, 11(2) or 12(1). Transitional vertebrae, 2(2) or 3(1). Displaced haemal spine 4(2).

Coloration in alcohol: Background colour yellowish. Head dark dorsally and gradually becoming lighter ventrally. Lips and suborbital region light yellow. Body yellowish dorsally, gradually becoming lighter to region overlying anal-fin pterygiophores. Four longitudinal dark stripes along body. Lateral-line stripe thin, one scale deep, extending from first perforated lateral-line scale to distal portion of caudal filament. Lateral-line stripe hardly discernible in specimens over 100 mm LEA. Superior medial stripe thick, two scales deep, tapering from vertical between base of anal-fin rays 12–22 to posterior one-third of body. Inferior medial stripe moderately thick, two scales deep, extending from vertical between base of anal-fin rays 10–13 to posterior one-third of body. Anal-fin base stripe thick, two scales deep, extending from vertical between base of analfin rays 12–15 to last anal-fin ray. Pectoral and anal fins hyaline, with scattered tiny chromatophores on interradial membranes.

Distribution: Eigenmannia vicentespelaea is known from the Caves of São Vicente I and II, Rio São Vicente, tributary of Rio Tocantins basin, Goiás, Brazil ( Fig. 6 ).

Remarks: Eigenmannia vicentespelaea was diagnosed by the extreme reduction of eyes ( Triques, 1996: 3). Subsequently, Bichuette & Trajano (2006) proposed an expanded diagnosis for E. vicentespelaea based on a larger sample of specimens, and using statistical data and colour-pattern characters to distinguish the species from an undescribed epigean congener (‘ Eigenmannia sp. ’ in Bichuette & Trajano, 2006). In view of intraspecific variability in the development of the eyes in E. vicentespelaea , which ranges from eyes completely absent ( Triques, 1993; Bichuette & Trajano, 2006) to eyes fully developed (e.g. MZUSP 83470), the diagnosis for E. vicentespelaea herein uses a combination of morphometric, meristic, and osteological features.

Material examined

Type specimens: Brazil. Goiás: MZUSP 42605 , holotype , 114.9 mm LEA, Cave of São Vicente II, São Domingos karst area, Rio São Vicente, Rio Tocantins basin, 13°35′ S, 46°22′ W. MZUSP 47984 , 1 paratype , 157.4 mm LEA.

Non-type specimens: Brazil. Goiás: MZUSP 83461 , 3 + 1CS, 108–164.5 mm LEA, Cave of São Vicente I, Rio São Vicente, Rio Tocantins basin, approximately 13°35′30″ S, 46°21′ W. All from Cave of São Vicente II, Rio São Vicente, Rio Tocantins basin, 13°35′ S, 46°22′ W, MZUSP 55989 , 2 , 109.2 – 110.9 mm LEA, MZUSP 83462 , 2 , 117.2 – 121.9 mm LEA, MZUSP 83463 , 1 CS, 118.9 mm LEA, MZUSP 83464 , 1, 161.6 mm LEA. MZUSP 83465 ,

2, 106.2– 109.2 mm LEA. MZUSP 83466, 1, 119.0 mm LEA. MZUSP 83467, 3, 109.7– 123.3 mm LEA. MZUSP 83468, 3, 81.6–116.2 mm LEA. MZUSP 83469, 1, 112.1 mm LEA. MZUSP 83470, 3, 83.6–95.6 mm LEA. MZUSP 83471, 1CS, 106.7 mm LEA.

Figures

Figure 5. Medial view of dentary: A, Eigenmannia vicentespelaea (MZUSP 83461, 152.1 mm LEA); B, Eigenmannia antonioi sp. nov. (MPEG 10182, 88.7 mm LEA), showing differents lengths of coronomeckelian bone, equal to 45% the length of Meckel’s cartilage in E. vicentespelaea and to 20% the length of Meckel’s cartilage in E. antonioi sp. nov. Abbreviations: ang-art, anguloarticular; mc, Meckel’s cartilage; cb, coronomeckelian bone; d, dentary; r, retroarticular. Cartilage represented by grey. Scale bars: 2 mm.

Figure 6. Map of South America showing the distribution of Eigenmannia antoinoi sp. nov., Eigenmannia desantanai sp. nov., Eigenmannia guairaca sp. nov. sp. nov., Eigenmannia matintapereira sp. nov., Eigenmannia microstoma (1 = type locality), Eigenmannia muirapinima sp. nov., Eigenmannia pavulagem sp. nov. (2 = type locality), Eigenmannia trilineata (3 = type locality), Eigenmannia vicentespelaea, and Eigenmannia waiwai sp. nov. Some symbols represent more than one lot and/or locality.

Figure 21. Lateral view of Eigenmannia vicentespelaea, MZUSP 83461, 108.5 mm LEA, Cave São Vicente I, Rio São Vicente, Rio Tocantins basin, Goiás, Brazil, approximately 13°35′30″ S, 46°21′ W.

Figure 22. Lateral view of head of Eigenmannia vicentespelaea, MZUSP 83461, 108.5 mm LEA, Cave São Vicente I, Rio São Vicente, Rio Tocantins basin, Goiás, Brazil, approximately 13°35′30″ S, 46°21′ W.