Hollandichthys taramandahy, new species

Figs. 1-6

Hollandichthys multifasciatus (non Eigenmann & Norris, 1900). - Reis et al., 2003: 125 (endangered species in Rio Grande do Sul State, Brazil). - Thomaz et al., 2010: 1349 (in part): Table 1 (vouchers UFRGS 11792, UFRGS 11793) [see discussion below]. - Malabarba et al., 2013: 39 (short diagnosis, distribution and habitat).

Holotype. MCP 30000, 85.8 mm SL, male, Brazil, Rio Grande do Sul, Maquiné, Barra do Ouro locality, tributary of rio do Ouro, rio Tramandaí system, 29 o 35’18”S 50 o 17’35”W, 25 Jan 2001, L. R. Malabarba, V. A. Bertaco, J. A. Anza & T. Hasper.

Paratypes. Brazil, Rio Grande do Sul, Maquiné, rio Tramandaí system, rio Maquiné drainage: MCP 26969, 15, 32.6-85.8 mm SL, collected with holotype. MCN 19693, 5, 43.4-75.5 mm SL, lateral puddle of arroio Encantado, 29 o 35’31”S 50 o 14’10”W, 12 Dec 2012, V. A. Bertaco, M. A. Azevedo & C. L. Castilho. MCP 24621, 13 (3 c&s), 38.6-87.8 mm SL, same locality of holotype, 31 Aug 1999, F. G. Becker, T. Finkler & M. Vassiliou. MCP 25273, 18 (3 c&s), 40.4-85.8 mm SL, same locality of holotype, 9 Dec 1999, F. G. Becker, V. A. Bertaco & P. Colombo. MCP 25416, 8, 36.8-69.5 mm SL, arroio Encantado, 29 o 36’28”S 50 o 12’15”W, 14 Nov 1999, F. G. Becker, P. Colombo & A. Brandt. MCP 25417, 1, 63.4 mm SL, arroio Pinheiro, 29 o 38’22”S 50 o 13’31”W, 15 Nov 1999, F. G. Becker, P. Colombo & A. Brandt. UFRGS 11793, 8, 47.9-88.2 mm SL, same locality of holotype, 14 Sep 2008, A. T. Thomaz, G. N. Mendes, J. F. dos Santos & J. M. Wingert. Itati, rio Três Forquilhas drainage: MCP 29244, 15 (2 c&s), 12.5-63.9 mm SL, creek tributary of arroio da Barra, 29 o 25’36”S 50 o 10’44”W, 25 Mar 2002, V. A. Bertaco & J. F. P. da Silva. UFRGS 16513, 13 (plus tissue samples), 37.0-64.0 mm SL, lateral puddle of arroio Bananeiras, near the mouth of arroio da Barra, 29 o 25’36”S 50 o 10’44”W, 6 Jun 2012, L. R. Malabarba, J. F. dos Santos, L. G. Artioli & P. Carvalho Neto. Santa Catarina, Praia Grande, rio Mampituba drainage: MCP 23625, 3, 35.7-78.5 mm SL, 21 Jul 1999, E. H. L. Pereira, R. E. Reis & J. F. P. da Silva; MCP 29241, 9, 29.4-45.6 mm SL, MCP 29242, 12 (2 c&s), 22.8-58.1 mm SL, arroio Molha Coco, 29 o 10’13”S 49 o 58’49”W, 25 Mar 2002, V. A. Bertaco & J. F. P. da Silva. MCP 29243, 4 (1 c&s), 37.1-71.9 mm SL, rio Mampituba, Praia Grande, 29 o 15’13”S 50 o 07’03”W, 25 Mar 2002, V. A. Bertaco & J. F. P. da Silva. UFRGS 11792, 8, 49.2-62.2 mm SL (includes the voucher TEC841B, 57.4 mm SL, GenBank Accession Numbers: SIA HM562824, Trop HM562798, 16S HM562736, COI HM562851 and ND2 HM562882; listed as H. multifasciatus by Thomaz et al., 2010), lateral puddle of rio Mampituba, 29°15’10”S 50°7’00”W, 14 Sep 2008, A. T. Thomaz, G. Neves, J. Ferrer & J. Wingert. Rio Araranguá drainage: MCN 19802, 18, 23.0- 55.5 mm SL, rio Serrinha, tributary of rio São Bento, rio Mãe Luzia basin, Treviso, ca. 28º27’S 49º30’W, Mar 2013, C. Feltrin. UFRGS 11791, 4, 35.3-82.8 mm SL, stream at Serra da Rocinha, Timbé do Sul, 28º47’27”S 49º55’44”W, 13 Sep 2008, A. T. Thomaz, G. Neves, J. Ferrer & J. Wingert.

Paragenetype. GenBank Accession Numbers: from voucher (TEC842 E, 57.3 mm SL) on lot UFRGS 11793, Sia HM562823; Trop HM562799; 16S HM562735; COI HM562852, ND2 HM562883 (from Thomaz et al., 2010: Table 1); from voucher MCP 26969/38, COI JF836373; MCP 26969/39, COI JF836374; MCP 26969/40, COI JF836375; MCP 26969/41, COI JF836376; MCP 26969/42, COI JF836377.

Diagnosis. Hollandichthys taramandahy can be diagnosed from H. multifasciatus by the presence of a small, vertically expanded black spot at base of median caudal-fin rays (Figs. 1-4), clearly visible after fixation in formalin or alcohol (vs. absence of a black spot on caudal fin, Fig. 7); adipose fin without distinctive marks (vs. anterior portion of adipose fin black, Fig. 7); absence of humeral spot on specimens larger than 60.0 mm SL (vs. humeral spot always present, Fig. 7; two black humeral spots present on small specimens of both species). Furthermore, H. taramandahy can be distinguished from H. multifasciatus by the number of dorsal procurrent caudal-fin rays (8-11, mode = 10, n = 20, vs. 10-15, mode = 12, n = 72, respectively) and ventral procurrent caudal-fin rays (7-8, mode = 8, n = 20, vs. 9-12, mode = 10, n = 72, respectively), and by the shorter length of the penultimate branched anal-fin ray in adult males (9.0- 12.3 in SL, mean = 10.5 vs. 11.1-20.8 in SL, mean = 14.9, respectively).

Description. Morphometric data summarized in Table 1. Body compressed and elongate; greatest body depth anterior to dorsal-fin origin. Dorsal head profile gently concave. Snout slightly pointed. Dorsal body profile slightly convex from supraoccipital bone to base of last dorsal-fin ray and straight from this point to adipose-fin origin. Ventral body profile convex from anterior tip of lower jaw to pelvic-fin origin and straight from the latter point to anal-fin origin. Body profile along anal-fin base posterodorsally slanted. Caudal peduncle nearly straight to slightly concave along dorsal and ventral margins.

Mouth slightly superior. Lower jaw protruding anteriorly with respect to upper jaw. Maxilla extending posteriorly to vertical through center of eye, and aligned at angle of approximately 45 degrees to longitudinal body axis.

Premaxilla with two tooth rows; outer row with two or three*, rarely four, tricuspid teeth with central cusp longest; inner row with five teeth, with three to five cusps (fourth or fifth cusp diminute); central cusp three or four times longer and broader than other cusps; symphyseal tooth much longer than remaining teeth. Maxilla with 13-17 (usually 13-14, 15*) tricuspid teeth, with central cusp longer. Four or five anteriormost dentary teeth large, with three to four cusps (fourth cusp diminute), followed by one medium sized tricuspid tooth, and 7-12 teeth with two to three cusps, rarely conical; central cusp in all teeth three or four times longer and broader than other cusps.All cusp tips slightly curved towards oral cavity (Fig. 5).

Dorsal-fin rays ii,9* (n = 51); first unbranched ray approximately one-half the length of second ray. Dorsal-fin origin posterior to middle of SL and posterior to vertical through pelvic-fin origin. Dorsal-fin profile slightly rounded. Unbranched and anterior 3 to 4 dorsal-fin rays bearing large posterior flap along posterolateral borders, more developed in specimens larger than 60 mm SL, extending along entire length of first unbranched ray and proximal midlength of second unbranched and anterior branched rays. Adipose fin located approximately at vertical through insertion of 20 th- 22 th anal-fin rays.

Anal-fin rays iii-v,27-30 (iii,28*; rarely 26, mode = 29, n = 51). First unbranched ray usually only apparent in c&s specimens. Anal-fin origin at vertical through base of third to fourth branched dorsal-fin rays. Unbranched and anterior two to three branched anal-fin rays bearing a large posterior flap along their posterolateral borders, more developed in larger specimens of both sexes, extending along entire length of anterior unbranched rays and proximal midlength of last unbranched and anterior branched rays.

Pectoral-fin rays i,11-14* (mode = 13, n = 51). Pelvic-fin rays 6,i* (rarely 5,i, n = 51). First pelvic-fin ray unbranched in specimens smaller than 35.0 mm SL, and branched in larger specimens (Fig. 6). Pelvic-fin origin anterior to vertical through dorsal-fin origin. Caudal fin forked, lobes similar in size, i,17,i* principal rays (n = 50, one specimen with i,16,i). Caudal-fin lobes slightly rounded. Presence of irregular small scales at base of lower caudal-fin lobe, extending posteriorly to vertical through one-half the length of middle caudal-fin rays. Dorsal procurrent caudal-fin rays 8-11 (mode = 10, n = 20). Ventral procurrent caudal-fin rays 7-8 (mode = 8, n = 20).

Scales cycloid, moderately large; some body scales on flanks with posterior margin truncate or concave. Lateral line incomplete, perforated scales 6*-9 (mode = 8, n = 50). Longitudinal series of scales including lateral-line scales 37- 40, rarely 41 (39*; mode = 38, n = 50). Scale rows between dorsal-fin origin and lateral line 6-7* (mode = 7, n = 51); scale rows between lateral line and pelvic-fin origin 5-6* (mode = 6, n = 51). Predorsal scales 12-16 (14*; mode = 14, n = 45), arranged in irregular series. Scale rows around caudal peduncle 14*-16 (mode = 14, n = 50). Axillary scale on pelvic-fin origin extending posteriorly covering one scale. Single series of 8-15 scales on scale sheath along anal-fin base (11*, n = 47), extending to base of sixth to twentieth branched rays.

Precaudal vertebrae 16-18; caudal vertebrae 20-21; total vertebrae 36-39, usually 37 (n = 6). Supraneurals 6-7 (n = 6). Gill-rakers of first gill arch 7 on upper limb and 10-11 on lower limb (n = 6).

Color in alcohol. Ground color dark yellow in dorsal region of body and head, gradually lighter on sides. Dark brown longitudinal lines usually forming a zigzag pattern between longitudinal rows of scales, except immediately above anal-fin base; more conspicuous along the longitudinal axis of the body, more visible in specimens larger than 50.0 mm SL (Fig. 1). Small black chromatophores scattered over rays of all fins. Adipose fin without distinctive marks, except for the anterodorsal border smoothly light gray pigmented. Small black spot vertically expanded at base of median caudal-fin rays (Figs. 1-2). Specimens measuring 42.0-50.0 mm SL with one or two faint and vertically elongate humeral spots. Color pattern of specimens smaller than 41.0 mm SL similar to that of large specimens, but always with two black vertically elongate humeral spots; anterior diffuse, located over first to fourth perforated lateral-line scales and sometimes extending over horizontal series of scales just above lateral line. Second humeral spot darker, located over seventh to eighth perforated lateral-line scales and sometimes extending over horizontal series of scales just above lateral line. Specimens larger than 60.0 mm SL without humeral spots (Figs. 1-2). Specimens up to 45 mm SL with chevron-shaped striae posteriorly diverging from longitudinal line, following miosepta. The remaining fins with dispersed dark cromatophores. Anal fin of specimens larger than 50 mm SL with one longitudinal black band along its middle-distal portion.

Color in life. Overall coloration light golden to greenish, except for the lateral and ventral portions of head and belly with ground coloration white. Anterior portion of dentary and dorsal portion of snout yellow. Iris dark brown above and below pupil and bright yellow anterodorsally. Tip of pelvic fin and adipose fin yellow; tip of the anterior lobe of the anal fin reddish, caudal fin light orange to reddish and dorsal and pelvic fins hyaline in a young male (Fig. 3). All fins yellow in an unsexed young specimen with 41 mm SL (Fig. 4). Specimens smaller than 41.0 mm SL with two black vertically elongate humeral spots, first spot diffuse and second spot more conspicuous (Fig. 4). Caudal fin spot hardly discernible in live specimens (Figs. 3 and 4). Dark brown longitudinal lines more conspicuous along the longitudinal axis of the body. Specimens up to 41 mm SL (Fig. 4) with chevron-shaped striae posteriorly diverging from longitudinal line, following myosepta.

Sexual dimorphism. Males of H. taramandahy are easily recognized by the presence of bony hooks on branched rays of anal and pelvic fins. Anal-fin rays of sexually mature males bear one pair of small, elongate, retrorse bony hooks along posterolateral border of each segment of lepidotrichia, along third through 27 th (usually fourth to 23 th) branched rays; hooks more numerous along seventh through 20 th branched rays, rarely present on 27 th ray. Hooks usually located along posteriormost branch and distal half to two thirds of each ray. Pelvic fin of males usually bearing one retrorse bony hook per segment of lepidotrichia along ventromedial border of third to fifth branched rays.

Anal-fin profile nearly straight along most of its ventral border in males, except for a concavity in the posterior portion, corresponding approximately to the position of the 20 th to 25 th rays; three or four posteriormost branched anal-fin rays longer than other rays, forming a conspicuous anal-fin lobe; penultimate ray longest (Figs. 1 and 3). Anal-fin profile nearly straight in all its extension in females (Fig. 2).

Males and females also differ in proportions of the pectoral- and pelvic-fin lengths (Table 1). Caudal peduncle depth slightly wider in males than females, and procurrent caudal-fin rays more developed in males. Gill glands (Burns & Weitzman, 1996) were not observed macroscopically on first gill arch in either males or females.

Distribution. Hollandichthys taramandahy in known from smaller tributaries of the rio Maquiné and rio Três Forquilhas, rio Tramandaí system, Rio Grande do Sul and from rio Mampituba and Araranguá drainages, Santa Catarina, Brazil. Rio Maquiné represents the meridional limit of distribution of the genus (Fig. 8).

Etymology. The species name, taramandahy, is in reference to the drainage of the type locality. In Tupi Guarani language, Taramandahy (=Tramandaí) means winding river, or where is about to harvest (related to fish harvesting). A noun in apposition.

Ecological notes. All specimens were caught in lateral puddles of rivers and very small tributaries with shallow and lentic black waters, with mud and leaf on the bottom, and very dense riparian vegetation, similar to what was observed by Sabino & Castro (1990) for H. multifasciatus in an Atlantic Forest stream in Ubatuba, São Paulo State, southeastern Brazil. The larger specimens (70.0-80.0 mm SL) were found isolated and small specimens (30.0-40.0 mm SL) were captured in groups of 3 to 6 fishes, as also observed by Sabino & Castro (1990) for H. multifasciatus. Although extensive collection efforts have been applied in sampling fishes along the last 30 years in the rio Maquiné, rio Três Forquilhas and rio Mampituba drainages, H. taramandahy was never caught in the main river itself, characterized by having clear and lotic water, stones on the substrate, and few riparian vegetation. Stomach contents of three specimens (MCP 24621) prepared for clearing and staining consisted of spiders, ants, beetles, and insect parts. Other species collected along with H. taramandahy were Astyanax laticeps, Astyanax sp., Cyanocharax itaimbe, Cyphocharax voga, Gymnotus sp., Hyphessobrycon luetkenii, Mimagoniates rheocharis, Phalloceros spiloura, and Steindachnerina biornata.

Conservation note. Hollandichthys taramandahy was listed as endangered species in the state of Rio Grande do Sul, Brazil (Reis et al., 2003), but named as H. multifasciatus (popular name Lambari-listrado). The species is threatened due to its very limited distribution range, in areas subject to high level of anthropogenic disturbances, e.g., deforestation of stream margins.