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A new Ancistrus species is described from Tapajós and Xingu river basins. It is distinguished from its congeners by the singular body color pattern, consisting of dark vermiculated stripes almost all over the body, and also by combination of features as a narrow head, large internostril distance, and absence of rows of enlarged odontodes on the lateral plates. In addition, the new species is distinguished from congeners that inhabit the rio Tapajós basin by the presence of a fully-developed adipose fin (vs. adipose fin absent in Ancistrus parecis and A. tombador, and vestigial adipose fin or absent in A. krenakarore). It differs from A. ranunculus, also from the rio Xingu, by the color pattern, smaller body size, smaller gill opening, and narrower cleithral width. The new taxon adds a new record to the list of species shared among the Xingu and Tapajós basins.
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Original article
Neotropical Ichthyology
Neotropical Ichthyology, 20(1):e210129, 2022
A new species of
Ancistrus
(Siluriformes: Loricariidae) from
Tapajós and Xingu basins, Brazil
Emanuel B. Neuhaus1, Marcelo R. Britto1, José Luís O. Birindelli2 and
Leandro M. Sousa3
A new Ancistrus species is described from Tapajós and Xingu river basins. It is
distinguished from its congeners by the singular body color pattern, consisting
of dark vermiculated stripes almost all over the body, and also by combination of
features as a narrow head, large internostril distance, and absence of rows of enlarged
odontodes on the lateral plates. In addition, the new species is distinguished from
congeners that inhabit the rio Tapajós basin by the presence of a fully-developed
adipose fin (vs. adipose fin absent in Ancistrus parecis and A. tombador, and vestigial
adipose fin or absent in A. krenakarore). It differs from A. ranunculus, also from
the rio Xingu, by the color pattern, smaller body size, smaller gill opening, and
narrower cleithral width. The new taxon adds a new record to the list of species
shared among the Xingu and Tapajós basins.
Keywords: Amazon, Brazilian Shield, Bristlenose pleco, Hypostominae,
Taxonomy.
1 Programa de Pós-graduação em Ciências Biológicas (Zoologia), Universidade Federal do Rio de Janeiro, Museu Nacional,
Departamento de Vertebrados, Setor de Ictiologia, Quinta da Boa Vista, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil.
(EBN) ebnsl@yahoo.com.br (corresponding author), (MRB) mrbritto@mn.ufrj.br.
2 Universidade Estadual de Londrina, Centro de Ciências Biológicas, Departamento de Biologia Animal e Vegetal, Rodovia Celso
Garcia Cid, km 380, Câmpus Universitário, 86051990 Londrina, PR, Brazil. josebirindelli@yahoo.com.
3 Universidade Federal do Pará, Câmpus Altamira, Rua Coronel José Porfírio, 2515, São Sebastião, 68372-040 Altamira, PA, Brazil.
Leandro.m.sousa@gmail.com.
Correspondence:
Emanuel B. Neuhaus
ebnsl@yahoo.com.br
Online version ISSN 1982-0224
Print version ISSN 1679-6225
Neotrop. Ichthyol.
vol. 20, no. 1, Maringá 2022
Submitted August 16, 2021
Accepted December 15, 2021
by George Mattox
Epub March 21, 2022
https://doi.org/10.1590/1982-0224-2021-0129
urn:lsid:zoobank.org:pub:706B55DE-8ED7-4A78-96F5-893669685C7C
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New Ancistrus from Tapajós and Xingu
Uma nova espécie de Ancistrus é descrita das bacias dos rios Tapajós e Xingu.
Distingue-se de suas congêneres pelo padrão de colorido único, que consiste em
listras vermiculadas escuras em quase todo o corpo, e também pela combinação de
características como cabeça estreita, maior distância entre as narinas e ausência de
séries de grandes odontódeos nas placas laterais. Adicionalmente, a nova espécie
pode ser diferenciada de suas congêneres da bacia do rio Tapajós pela presença
de uma nadadeira adiposa totalmente desenvolvida (vs. nadadeira adiposa ausente
em Ancistrus parecis e A. tombador, nadadeira adiposa vestigial ou ausente em A.
krenakarore). Ela difere de A. ranunculus, a única outra espécie do rio Xingu, pelo
padrão de colorido, menor tamanho corporal, menor abertura branquial e menor
largura entre os cleitros. O novo táxon adiciona um novo registro à lista de espécies
compartilhadas entre as bacias do Xingu e Tapajós.
Palavras-chave: Amazônia, Cascudo, Escudo Brasileiro, Hypostominae,
Taxonomia.
INTRODUCTION
The genus Ancistrus Kner, 1854 includes 75 valid species (Fricke et al., 2021) distributed
in South and Central Americas from Panama to Argentina, occurring in cis- and trans-
Andean rivers. Among Loricariidae, the diversity of Ancistrus is only smaller than that
of Hypostomus Lacepède, 1803. Ancistrus is easily distinguished from other loricariids
by having naked snout margins (i.e., without plated snout, Figs. 1, 2) bearing fleshy
expansions (tentacles). The genus Chaetostoma Tschudi, 1846 also has unplated snout,
but differs from Ancistrus by the absence of fleshy tentacles and by having five plate
rows at the narrowest part of the caudal peduncle (vs. three plate rows in Ancistrus). As
for other highly diverse genera of Neotropical fish, the diversity of Ancistrus remains
underestimated. In addition, more than half of valid species were described before
1950 in poorly-informative descriptions that leave doubt of the species delimitations.
Consequently, there are a large number of possibly undescribed species, several of
them highly appreciated in the ornamental fish trade. To overcome the taxonomic
issues, aquarium fish hobbyists apply an alphanumeric code (the L-number system) to
provisionally name the putative new species and morphotypes that appear in the hobby
(Stawikowski, 1988).
Recent ichthyological surveys in the Brazilian Shield Amazon rivers captured several
specimens of Ancistrus with a distinctive color pattern in the Tapajós and Xingu river
basins. The specimens from the Xingu drainage are already known by aquarists by
the code L159 (Stawikowski, 1994; Dignall, 2014). The present contribution aims to
describe the new species, illustrating and diagnosing it, with comparisons to congeners.
MATERIAL AND METHODS
Measurements were obtained with digital calipers to the nearest 0.1 mm. Measurements
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Emanuel B. Neuhaus, Marcelo R. Britto, José Luís O. Birindelli and Leandro M. Sousa
and counts were made only in the left side of the body, except when not possible,
excluding the infraorbitals that were counted in both sides. Most morphometric data
were taken following Fisch-Muller et al. (2001), and Armbruster (2003), in addition
to nares-eye distance taken from posterior border of left naris to anterior border of
left eye. Morphometrics are reported as percentages of standard length (SL), except
for subunits of head which are reported as percentages of head length (HL). Plate
terminology follows Schaefer (1997) and osteological nomenclature is according to
Schaefer (1987), except for prefrontal plate used to name the plate which forms the
posterolateral nostril margin and anterodorsal orbit margin (Schaefer, 1997), and
compound pterotic used instead of pterotic-supracleithrum (Aquino, Schaefer, 2002).
Terminology for snout areas of tentacles follows Sabaj et al. (1999). Some specimens
were cleared and stained (cs) according to the protocol of Taylor, Van Dyke (1985).
Meristic data follows Armbruster (2003) with addition of: complete series of mid-dorsal
and mid-ventral plates; plates along dorsal-fin base: dorsal plates between dorsal-fin
spine and the insertion of the last dorsal-fin branched ray; plates between end of the
dorsal fin and adipose-fin origin: dorsal plates posterior to the insertion of the last
dorsal-fin branched ray and adipose-spine origin; plates between adipose and caudal
fins: dorsal plates between end of adipose-fin membrane and caudal fin; preanal plates:
ventral plates before unbranched ray of anal fin; ventral plates between anal-fin base and
caudal fin; vertebral count including those of the Weberian-complex and the counting
the PU1+U2 as a single element; number of ribs; number of left and right infraorbitals;
number of pterygiophores of the dorsal fin.
In the description, numbers between brackets represent the total number of specimens
with those counts, whereas asterisks indicate counts of the holotype. Comparative data
of Ancistrus caucanus Fowler, 1943, A. dolichopterus Kner, 1854, A. dubius Eigenmann &
Eigenmann, 1889, A. eustictus (Fowler, 1945), A. hoplogenys (Günther, 1864), A. latifrons
(Günther, 1869), and A. malacops (Cope, 1872) were obtained through their original
descriptions and photographs of type-specimens available from Morris et al. (2006).
Institutional abbreviations follow Sabaj (2020). Due to the wide distribution of the new
species and consequent variation of diagnostic features, we restricted the type-series to
specimens from the Teles Pires basin. Therefore, the non-type series embraces non-
measured specimens, specimens in no good condition for reliable identification, live
specimens and specimens from the Xingu basin.
RESULTS
Ancistrus luzia
, new species
urn:lsid:zoobank.org:act:31D5520F-B248-4226-8413-896A0535A341
(Figs. 1–3; Tab. 1)
Ancistrus L 159. ―Stawikowski, 1994:145 [DATZ magazine, new imports from Brazil, figs. 6
and 7].
Ancistrus sp. “lineolatus”. ―Ohara et al., 2017:259 [identification guidebook from Teles Pires].
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New Ancistrus from Tapajós and Xingu
Holotype. MNRJ 51458, male, 75.9 mm SL, Brazil, Mato Grosso, Guarantã do
Norte, rio Teles Pires basin, unknown stream next to bridge on road about 8 km from
the road BR-163, 09°47’15”S 54°57’33”W, 1 Oct 2008, M. R. Britto, J. Gomes, F. R.
Carvalho & L. Fries.
FIGURE 1 | Ancistrus luzia, holotype, MNRJ 51458, male, 75.9 mm SL, Brazil, Mato Grosso, Guarantã do
Norte, a tributary of rio Teles Pires, Tapajós basin. Black spots in the ventral view are parasites.
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Emanuel B. Neuhaus, Marcelo R. Britto, José Luís O. Birindelli and Leandro M. Sousa
Paratypes. Brazil, Mato Grosso, rio Tapajós basin: MNRJ 35484, 11, 26.1–74.7
mm SL (10, 33.4–74.7 mm SL), collected with the holotype. MNRJ 24622, 9, 1 cs,
33.2–62.9 mm SL, Terra Nova do Norte, riacho Doce, tributary of rio Bastião, rio Teles
Pires basin, 10°33’00”S 55°4’25”W, 23 Jan 2002, P. Buckup, A. Aranda, F. Silva & C.
Figueiredo. MNRJ 24641, 3, 47.8–52.2 mm SL, Peixoto de Azevedo, tributary of rio
Peixoto de Azevedo at road BR-080, rio Teles Pires basin, 10°25’57”S 54°10’59”W, 24
Jan 2002, P. Buckup, A. Aranda, F. Silva & C. Figueiredo. MNRJ 24692, 2, 58.6–71.2
Holotype N Range Mean SD
Standard length 75.9 65 33.2–82.9
Percents of standard length
Predorsal length 48.0 65 44.3–48.4 46.3 1.0
Head length 37.9 65 34.9–39.8 36.9 1.0
Dorsal spine length 25.9 50 22.0–29.1 26.1 1.4
Anal-fin unbranched ray length 10.2 58 7.2–11.4 8.7 0.8
Pectoral spine length 30.2 65 26.8–34.6 30.4 1.7
Pelvic-fin unbranched ray length 24.9 65 23.2–28.9 26.1 1.2
Adipose spine length 7.0 65 5.4–8.6 7.2 0.8
Upper caudal-fin unbranched ray length 26.3 42 20.0–28.5 25.8 1.8
Lower caudal-fin unbranched ray length 33.2 51 26.5–40.6 35.2 2.9
Cleithral width 33.2 65 30.8–35.1 33.2 1.0
Body width at dorsal fin origin 26.9 64 24.0–32.0 27.2 1.5
Caudal peduncle length 28.9 65 28.9–35.0 32.3 1.1
Caudal peduncle depth 11.8 65 10.0–12.0 10.9 0.4
Dorsal-fin base length 20.8 65 19.6–23.8 21.7 0.9
Dorsal-adipose distance 20.2 65 17.5–22.8 20.5 1.0
Interbranchial distance 19.0 65 18.6–22.1 20.2 0.8
Thoracic length 23.7 65 22.7–27.8 24.9 1.2
Abdominal length 23.3 65 21.8–25.0 22.9 0.7
Head-pectoral length 29.4 65 26.3–31.4 29.0 0.9
Percents of head length
Snout length 58.6 65 48.5–61.7 58.1 2.0
Orbital diameter 17.7 65 15.6–22.3 19.5 1.5
Interorbital width 45.9 65 39.7–47.3 43.4 1.8
Internostril distance 22.5 65 18.7–23.7 21.1 1.2
Orbital-nostril distance 6.7 65 6.7–9.7 8.1 0.8
Occipital depth 53.2 65 42.7–57.3 48.2 2.7
Mouth width 53.3 61 44.4–70.7 56.5 5.7
Head-eye length 42.2 65 36.2–44.8 41.0 1.4
Mouth length 47.9 62 40.3–52.1 47.7 2.3
Premaxillary tooth cup length 12.1 62 10.1–19.4 13.5 2.2
Dentary tooth cup length 11.1 64 8.8–18.0 11.9 1.7
TABLE 1 | Morphometric data of Ancistrus luzia. N = number of specimens; SD = standard deviation.
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New Ancistrus from Tapajós and Xingu
mm SL, Carlinda, tributary of rio Teles Pires, left margin, at road MT-208, 09°59’04”S
55°46’03”W, 23 Jan 2002, P. Buckup, A. Aranda, F. Silva & C. Figueiredo. MNRJ
35486, 3, 1 cs, 56.2–60.9 mm SL, Guarantã do Norte, tributary of rio Braço do Norte,
Teles Pires basin, 09°56’55”S 55°01’51”W, 2 Oct 2008, P. Buckup, J. Maldonado, J.
Birindelli, C. Chamon & W. Felzmann. MNRJ 35487, 11, 25.6–34.9 mm SL (1, 34.9
mm SL), Novo Mundo, stream and wetland at the road between Novo Mundo and
Alta Floresta, 10°03’37”S 55°26’54”W, 2 Oct 2008, M. Britto, J. Gomes, F. Carvalho,
L. Fries, F. Jerep & C. Zawadzki. MNRJ 35489, 2, 52.0–77.1 mm SL, Alta Floresta,
corredeira Boca Quente, rio Teles Pires, 09°38’42”S 55°59’23”W, 3 Oct 2008, M.
Britto, J. Gomes, C. Chamon, L. Fries, F. Jerep & C. Zawadzki. MZUEL 20724, 2,
40.2–54.6 mm SL, collected with the holotype. MZUEL 20725, 1, 69.0 mm SL, Alta
Floresta, corredeira Boca Quente, rio Teles Pires, 09°38’42”S 55°59’23”W, 3 Oct 2008,
M. Britto, J. Gomes, C. Chamon, L. Fries, F. Jerep & C. Zawadzki. MZUEL 20726,
1, 64.3 mm SL, Carlinda, tributary of rio Teles Pires, left margin, at road MT-208,
09°59’04”S 55°46’03”W, 23 Jan 2002, P. Buckup, A. Aranda, F. Silva & C. Figueiredo.
MZUSP 62659, 8 (4, 42.6–54.8 mm SL), Claudia, córrego Loanda, at road BR-163, rio
Teles Pires, 11°25’00”S 55°21’00”W, 21 Feb 1998, M. I. Landim & C. Moreira. MZUSP
95904, 6 (3, 61.0–82.9 mm SL), Itauba, rio Teles Pires, 11°03’44”S 55°19’08”W, 26 Sep
2007, J. Birindelli & P. H. Carvalho. MZUSP 96150, 4 (2, 54.9–55.1 mm SL), Paranaíta,
rio Teles Pires, 09°26’58”S 56°29’19”W, 28 Sep 2007, L. Sousa & A. Netto-Ferreira.
MZUSP 96820, 46, 1 cs (5, 45.7–79.5 mm SL), Peixoto de Azevedo, Cachoeira da
Neblina, in a tributary of rio Peixoto de Azevedo, rio Teles Pires, 18 Oct 2007, J.
Birindelli, L. Sousa, A. Netto-Ferreira, M. Sabaj-Perez & N. Lujan. Pará, rio Tapajós
basin: MZUSP 96834, 4 (2, 22.1–29.1 mm SL), Novo Progresso, tributary of rio
Braço do Norte, rio Peixoto de Azevedo, rio Teles Pires, at bridge of the road BR-163,
09°25’55”S 54°52’11”W, 19 Oct 2007, J. Birindelli, L. Sousa, A. Netto-Ferreira, M.
Sabaj-Perez & N. Lujan. MZUSP 99877, 28 (18, 29.6–59.8 mm SL), Jacareacanga, rio
Teles Pires, downstream Sete Quedas, 09°18’42”S 56°46’47”W, 9 Jun 2008, L. Sousa &
A. Netto-Ferreira. MZUSP 99931, 4 (2, 58.7–61.1 mm SL), Jacareacanga, tributary of
the left margin of rio Teles Pires, downstream of Sete Quedas, 09°18’27”S 56°47’38”W,
9 Jun 2008, L. Sousa & A. Netto-Ferreira.
Non-types. Brazil, Mato Grosso, rio Tapajós basin: MNRJ 35490, 1, 40.4 mm
SL, Alta Floresta, cachoeira do Limão, at rio Cristalino, tributary right margin of rio
Teles Pires, 09°32’17”S 55°54’14”W, 4 Oct 2008, P. Buckup, F. Carvalho, J. Birindelli,
J. Gomes, F. Becker, R. Silvano & W. Felzmann. MNRJ 35491, 3, 53.6–61.8 mm SL,
Alta Floresta, igarapé Corgão, and adjacent margin of rio Peixoto de Azevedo, Teles
Pires basin, 09°43’37”S 55°50’06”W, 4 Oct 2008, P. Buckup, F. Carvalho, J. Birindelli,
J. Gomes, F. Becker, R. Silvano & W. Felzmann. MNRJ 35492, 1, 32.2 mm SL, Alta
Floresta, stream in front of Ilha do Refúgio, rio Teles Pires, 09°38’40”S 56°01’58”W,
4 Oct 2008, M. Britto, J. Gomes, C. Chamon, J. Maldonado, F. Jerep & C. Zawadzki.
MNRJ 35493, 1, 32.7 mm SL, Alta Floresta, Ilha do Domingão, rio Teles Pires,
09°38’13”S 55°58’55”W, 4 Oct 2008, M. Britto, J. Gomes, C. Chamon, J. Maldonado,
F. Jerep & C. Zawadzki. MZUSP 95639, 1, 36.7 mm SL, Paranaíta, rio Teles Pires,
near the ferry of the road MT-426, 09°27’07”S 56°30’46”W, 27 Sep 2007, L. Sousa &
A. Netto-Ferreira. MZUSP 96564, 1, Itaúba, stream at road BR-163, tributary of rio
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Emanuel B. Neuhaus, Marcelo R. Britto, José Luís O. Birindelli and Leandro M. Sousa
Teles Pires, 11°06’51”S 55°18’25”W, J. Birindelli & P. H. Carvalho. Pará, rio Xingu
basin: LIA 3996, 2, 39.0–42.0 mm SL, igarapé at Morro do Félix, RESEX do Rio
Xingu, Altamira, 05°22’18”S 52°55’37”W, 17 Set 2016, A. Gonçalves & M. D. Silva.
LIA 7657, 4, 25.1–66.1 mm SL, igarapé without name, 03°28’39”S 52°32’36”W, 15 Set
2012, D. Bastos. MNRJ 35483, 1, 34.1 mm SL, stream at road BR-163, about 14 km
north of Castelo dos Sonhos, 30 Sep 2008, M. Britto, J. Gomes, F. Carvalho & L. Fries.
MNRJ 35503, 2, 36.1–42.9 mm SL, Altamira, rio Curuá, rio Iriri basin, 08°06’35”S
55°00’58”W, 30 Set 2008, P. Buckup, J. Maldonado, C. Zawadski, C. Chamon & F.
Jerep. MNRJ 35504, 6, 22.5–48.5 mm SL (4, 37.5–48.5 mm SL), Altamira, rio Curuá,
rio Iriri basin, small stream upstream the first waterfall, 08°44’02”S 54°57’45”W, 1 Oct
2008, M. Britto, J. Gomes, F. Carvalho & L. Fries. MNRJ 35505, 8, 23.4–71.6 mm
SL (5, 36.9–71.6 mm SL), Altamira, rio Curuá, rio Iriri basin, waterfall of rio Curuá,
54 km from Castelo dos Sonhos, 08°44’06”S 54°57’43”W, 1 Oct 2008, M. Britto, J.
Gomes, F. Carvalho & L. Fries. MNRJ 35506, 2, 61.3–80.7 mm SL, rio Curuá, rio Iriri
basin, waterfall of rio Curuá, upstream the first waterfall, 08°44’10”S 54°57’47”W, 1
Oct 2008, M. Britto, J. Gomes, F. Carvalho & L. Fries. MZUEL 20727, 1, 62.5 mm SL,
rio Curuá, rio Iriri basin, waterfall of rio Curua, upstream the first waterfall, 08°44’10”S
54°57’47”W, 1 Oct 2008, M. Britto, J. Gomes, F. Carvalho & L. Fries.
Diagnosis. Ancistrus luzia is distinguished from its congeners, except A. claro Knaack,
1999 and A. centrolepis Regan, 1913, by the singular body color pattern, consisted of
dark-vermiculated stripes on head, dorsal and lateral plates of trunk (vs. body uniformly
colored or with light or dark spots or blotches over head or dorsal and lateral plates of
trunk). Ancistrus luzia is distinguished from A. claro by its narrower head (head width
30.8–35.1% vs. 35.2–38.2% HL) and greater internostril distance (18.7–23.7% vs. 14.9–
17.0% HL), and from A. centrolepis by the absence of rows of greatly enlarged odontodes
on the lateral plates (vs. presence of one to three rows of enlarged odontodes on the
lateral plates). Juveniles of A. leucostictus (Günther, 1864) might show lines similar to A.
luzia, but color changes to light, large spots as specimens grow. In addition, the new
species is distinguished from its congeners that inhabit the Tapajós basin by the presence
of adipose fin fully developed (vs. adipose fin absent in A. parecis Fisch-Muller, Cardoso,
da Silva & Bertaco, 2005, A. tombador Fisch-Muller, Cardoso, da Silva & Bertaco, 2005,
and vestigial adipose fin or absent in A. krenakarore de Oliveira, Rapp Py-Daniel &
Zuanon, 2016). Ancistrus luzia differs from A. ranunculus Muller, Rapp Py-Daniel &
Zuanon, 1994, the only described species from the rio Xingu, by the smaller body size
in adults, smaller gill opening (HL/interbranchial distance equals to 1.7 to 2.0 vs. 2.3 to
3.9) and narrower cleithral width (SL/cleithral width equals to 2.8–3.2 vs. 2.1–2.9).
Description. Morphometrics data in Tab. 1. Dorsal profile convex, ascending from
the tip of snout until posterior limit of supraoccipital; almost straight to slightly convex
between supraoccipital and dorsal-fin origin, descending from this point until posterior
margin of adipose-fin base; slightly concave between end of adipose and first procurrent
caudal-fin ray. Body width greatest at opercular region, progressively narrowing until
end of caudal peduncle. Greatest body height at dorsal-fin origin and lowest at the
caudal peduncle, near adipose-fin terminus. Body in cross section horizontally elliptical
at abdominal region and vertically oval at caudal peduncle. Ventral profile gently
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New Ancistrus from Tapajós and Xingu
convex between tip of snout and pelvic-fin origin, and then straight between pelvic fin
and first procurrent caudal-fin ray.
Body covered with bony plates, except along dorsal-fin base, and ventral region
between tip of snout and anal-fin origin. Plates arranged in four series from head to
pelvic-fin base, with ventral series absent. Plates arranged in five series in trunk from
pelvic-fin base to vertical through adipose-fin base with mid-dorsal and mid-ventral
series ending at the latter point. Plates arranged in three series at the narrowest part of
the caudal peduncle. Small sets of odontodes eventually occurring over the ventral skin
close to pectoral-fin insertion. Lateral line visible from posterior margin of compound
pterotic to posterior end of caudal peduncle, always following median plate series.
Body plates and fin rays covered with odontodes. Odontodes in regular rows on
the plates, larger on posterior margin. Some individuals have odontodes just before
insertion of unbranched anal-fin ray, arising from expanded transverse process of first
pterygiophore of anal fin. Odontodes larger on distal half of pectoral-fin spine and
partially covered with dermic membrane. Odontodes on pelvic-fin unbranched rays
larger at ventral portion. Median plates 23(9), 24*(53), 25(2), 26(1); mid-dorsal plates
10(2), 12(1), 13(4), 14(6), 15(16), 16*(19), 17(15), 18(1), 19(1); mid-ventral plates 18(3),
19(38), 20*(17), 21(6), 22(1); plates along dorsal-fin base 5(3), 6*(61), 7(1); plates between
end of dorsal and adipose fins 6(1), 7*(46), 8(17), 9(1); plates between adipose and caudal
fins, 2(41), 3*(24); preanal plates 2(1), 3(3), 4*(59), 5(2); ventral plates between anal-fin
base and caudal fin 12(4), 13*(54), 14(5), 15(1). Urogenital pore covered with tubular-
shape urogenital papilla.
Rounded snout, in dorsal view, with naked margin. See description on Sexual
Dimorphism for details on snout and tentacles. Presence of subdermal platelets
bordering the naked margin and/or in the base of tentacles (Fig. 2). Oral disc rounded,
with small papillae on its inner surface decreasing in size toward external margin. Lower
lip larger than upper, not reaching pectoral girdle. Barbel short, length nearly half of
orbit diameter and free from lower lip in most specimens. Bicuspid teeth with elongate
mesial cusp and short lateral cusp, cusps separated from each other by V-shaped notch;
49–76 (mean 62) teeth in premaxilla, 48–75 (mean 62) dentary. Post-opercular region
naked, with zero to eight dermal platelets normally grouped near anterior margin of
compound pterotic; 6–14 (mean 11) evertible cheek odontodes distally hooked, hyaline
at base and yellowish amber at tip.
Dorsal-fin origin slightly anterior to pelvic-fin origin; dorsal fin II,6(1), II,7*(63) or
II,8(1). First unbranched ray (spinelet) short and V-shaped (one specimen with spinelet
atrophied), second unbranched ray (dorsal spine) well developed. Last branched-rays
reaching or almost reaching pre-adipose plate, when adpressed. Pectoral fin I,6*(65),
when adpressed reaching pelvic-fin insertion in small individual (30 mm) or reaching
half-length of pelvic unbranched rays in larger specimens. Pelvic fin i,5*(65), with
posterior margin reaching approximately half of anal-fin rays. Anal fin i,3(1) or i,4*(63).
Caudal-fin truncate; i,14,i*(65); with upper lobe shorter than lower; dorsal and ventral
procurrent caudal-fin rays 5*(28) or 6(16) and 3(8), 4*(31), or 5(1), respectively.
Eyes rounded, located dorsolaterally on head. Orbit delimited dorsally by prefrontal
plate, frontal and sphenotic, and ventrally by infraorbitals four to six. Anterior and
posterior nares located dorsally on head, separated from each other by a flap of skin.
Anterior naris with tubular expansion of skin. Posterior naris separated from orbit by
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prefrontal plate and frontal. Six infraorbitals in total.
Palatine splint present in one specimen and absent the other two cleared and stained.
When present thin, elongate and ossified, located near palatine cartilage and lateral to
palatine. Four branchiostegal rays, only first one associated with posterohyal; remaining
three supported by branchiostegal membrane. Three basibranchial elements, only
first one ossified. Five pairs of hypobranchial elements, only first ossified. Five pairs
of ossified ceratobranchials; first with large accessory flange supporting first row of
modified gill rakers; fifth expanded, with numerous small teeth on dorsomesial edge,
and supporting row of modified gill rakers on dorsal surface. Four ossified epibranchials.
Two infrapharyngobranchials: one associated with third epibranchial and the other
with fourth. Upper pharyngeal tooth plates with teeth along entire ventral portion.
Vertebrae 27, with sixth vertebra and eighth to 14th(2) or 15th(1) vertebrae
bearing ribs. First rib (associated with sixth centrum) conspicuously larger. Neural
spine absent in vertebral centrum eight. Centra with bifid neural spines: 10–15(3). Bifid
neural arches reaching dorsal dermal plates, except for ninth centrum, reduced. Hemal
spines present on vertebrae 9–27(1) or 10–27(2) and reaching ventral dermic plates from
18th or 19th. Dorsal fin with eight pterygiophores, first two sutured to each other and
FIGURE 2 | Ancistrus luzia, paratype, MNRJ 24622, cs, female, 48.9 mm SL, showing the subdermal
platelets bordering the naked margin of snout. Arrows indicate platelets.
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to neural spine of seventh centrum, and in some specimens also to anterior portion of
eighth centrum; transverse process present on first five proximal radials; last one with
pair of elongate posterior processes. Branched rays of pectoral fin supported by three
radials. Lateral and internal pairs of anterior processes of basipterygia reaching each
other at central portion of pelvic girdle. First pterygiophore of anal fin contacting hemal
spine of centrum 14.
Color in alcohol. Ground color of head, dorsum and lateral portions of trunk brown,
with striated dark lines. In snout, dark lines somewhat parallel to each other, straight or
curved, eventually branched, and longitudinal to axis of body. Dark lines outline bones
of neurocranium and predorsal plates posterior to orbit. Lips yellowish brown. Ventral
region of abdomen brown, without lines or blotches (with exception of two specimens
of MNRJ 24622 that showed rounded dark brown blotches). All fins with brown
interradial membranes. Dorsal fin sometimes with a dark blotch at base of membrane,
between dorsal-fin spine and first branched ray. Dorsal-fin rays with two to five blotches
over rays usually expanded over membranes. Caudal fin with dark spots over rays and
interradial membranes, forming vertical, straight to sinuous and discontinuous stripes.
Vertical dark band close to caudal-fin base, posterior to platelets. Tips of caudal fin and
adjacent branched rays yellowish white or hyaline, some individuals with tip of dorsal
fin and adjacent branched rays hyaline. Color of pectoral and pelvic fins similar to dorsal
fin. Juveniles have caudal fin with wide, vertical dark band; some specimens with tip
of dorsal spine and adjacent branched rays, as well as tip of caudal-fin lobes red-brown
colored (MZUSP 99877; Figs. 3A, B). In populations from rio Curuá, the juveniles have
a similar color pattern described above (Figs. 3C, D). Nevertheless, in adults lateral and
dorsal plates do not have vermiculation but an inconspicuous dark longitudinal band
passing through median plates instead. Paired and dorsal fins without spots. Caudal fin
brown with base and distal portions dark brown. All membrane fins are brown (Fig. 4A).
FIGURE 3 | Color pattern of juvenile specimens of Ancistrus luzia. A, B. MZUSP 99877, 33.2 mm SL, from rio Teles Pires basin. C, D. MNRJ
35504, 37.5 mm SL, from the rio Curuá, rio Xingu basin.
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FIGURE 4 | Lateral view of Ancistrus luzia, MNRJ 35505, 71.6 mm SL, rio Curuá, Xingu basin. A.
Preserved specimen. B. Specimen in life.
Color in life. Live specimens show similar color pattern observed in specimens
preserved in alcohol, except for ground coloration more greenish, and dark lines more
conspicuous (Figs. 4B, 5, 6).
Sexual dimorphism. Naked margin of snout narrower in females and juveniles (width
smaller than distance between nares) and wide in adult males (width equal or greater than
distance between nares). Naked margin in nuptial males reaching the anterior margin
of nasal openings. Fleshy tentacles on naked region visible in individuals larger than 30
mm, well developed in nuptial males. Males with numerous and larger tentacles than
females but number and size vary among specimens of same sex and similar standard
length. Some adult females without tentacles (observed in MZUSP 96820). Tentacles
along the snout margin smaller and, with a few exceptions, unbranched. Most tentacles
branched in the medial row. Some mature females with yellowish-white dots around
urogenital papilla (Fig. 7).
Etymology. Named after “Luzia” (Lapa Vermelha IV Hominid 1), a female Homo
sapiens skeleton and one of the oldest human remains found in the Americas (11,000–
11,500 years before present), in 1974 and 1975 during excavations coordinated by the
French archaeologist Annette Lamin-Emperaire (1917–1977) from the site of Lapa
Vermelha IV, Lagoa Santa region, municipality of Pedro Leopoldo, state of Minas Gerais,
Brazil (Neves et al., 1999). The skeleton is deposited at Museu Nacional Biological
Anthropology collection (catalogue number 01959), Universidade Federal do Rio de
Janeiro, and was recovered again after the fire that hit the institution on September 2,
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FIGURE 5 | Ancistrus luzia in life, MZUSP 96564, rio Teles Pires, rio Tapajós basin.
2018 by Museu Nacional Rescue team, becoming a symbol of institutional hope and
resilience. A noun in apposition.
Geographical distribution. Ancistrus luzia is known from rio Teles Pires and its
tributaries (rio Tapajós basin) and small to medium tributaries of middle and upper rio
Xingu basin (Fig. 8) always associated with moderate water flow and rocky substrates
(Fig. 9).
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FIGURE 6 | Ancistrus luzia in life, specimen not preserved, 80.6 mm SL, rio Bacajaí, 03°35’13”S 51°46’00”W, tributary to middle rio Xingu.
Conservation status. Ancistrus luzia is widely distributed across the Teles Pires
basin and in different tributaries of the rio Xingu. A substantial number of cataloged
specimens from distinct localities and distinct field expeditions over the past two decades
suggest that the species is not threatened. In the rio Xingu, part of its tributaries at Volta
Grande region were flooded by the Belo Monte Hydropower dam, but specimens were
recently collected (non-cataloged material) in small streams not affected by the dam.
Thus, A. luzia may be categorized as Least Concern (LC) according to the categories
and criteria of the International Union for Conservation Nature (IUCN Standards and
Petitions Subcommittee, 2019).
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FIGURE 7 | Ventral view of pelvic girdle of Ancistrus luzia showing differences in urogenital papillae of female (63.2 mm SL) and male (80.6
mm SL).
FIGURE 8 | Geographic distribution of Ancistrus luzia. Star represents its type locality.
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FIGURE 9 | Habitats of Ancistrus
luzia: (above) rio Teles Pires,
Itauba, Mato Grosso (MZUSP
95904), photo by José L. O.
Birindelli; (middle) rio Bacajaí
(03°35’13”S 51°46’00”W ),
tributary to middle rio Xingu,
photo by Leandro Sousa; and
(below) igarapé without name,
Middle Xingu, Altamira, Pará
(LIA 7657), photo by Douglas
Bastos.
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DISCUSSION
Although there is a relatively large number of valid species allocated in Ancistrus, the
diversity of the genus remains underestimated. To overcome the lack of scientific names,
aquarium hobbyists developed an alphanumeric code system, the L-number system
(Stawikowski, 1988), to address possibly undescribed species. In the present paper, one
of these L-numbered species, the L159 (Stawikowski, 1994), is given a scientific name:
Ancistrus luzia.
Ancistrus luzia is the second species described from the Xingu basin and the fourth
from the Tapajós basin. Ancistrus ranunculus was described from the middle Xingu and
Tocantins basins (Muller et al., 1994) and differs from A. luzia by the color pattern (dark
body, without vermiculations vs. body brown with dark-line vermiculations), by the
wider gill opening (HL/interbranchial distance equals 2.3 to 3.9 vs. 1.7 to 2.0 in A. luzia)
and wider body (SL/cleithral width equals to 2.1–2.9 vs. 2.8–3.2). The three described
species from the Tapajós are easily distinguished by having adipose fin reduced, or absent.
Ancistrus parecis has its type locality in the rio Formiga, a tributary of rio Juruena (Fisch-
Muller et al., 2005b); A. tombador was described from the igarapé Ribeirão Preto, a tributary
of rio Arinos (Fisch-Muller et al., 2005a); and A. krenakarore has its type locality in the
rio Itapacurá, a right bank tributary of rio Tapajós (de Oliveira et al., 2016). According
to de Oliveira et al. (2016), the reduction of the adipose fin in these species probably
evolved independently due to their distinct development. In A. krenakarore, the spine and
a reduced membrane are present in juveniles, and they are gradually absorbed into the
skin during ontogenetic development (in a few cases, a vestigial fin can persist in adults).
On the other hand, in A. parecis and A. tombador, the adipose fin seems to be absent from
early developmental stages. In this case, small-unpaired dorsal plates form a crest that
replaces the fin.
There is no phylogenetic hypothesis including the species of Ancistrus treated herein.
In addition, no other valid species has a similar color pattern as that seen in A. luzia.
Nevertheless, the new species shares with congener’s small ossifications, not supporting
odontodes at the bases of each of the large tentacles, a feature first described in Armbruster
(2004). Moreover, some specimens of A. luzia bear weak subdermic platelets surrounding
the naked margin of snout but not associated to tentacles (Fig. 2). The presence of these
features could help to understand the evolution of the new species among congeners.
In addition to Ancistrus luzia, the Tapajós and the Xingu basins share several other
species. Buckup et al. (2011) registered 155 species occurring in both basins. According
to Dagosta, de Pinna (2017), tributaries of the upper Tapajós, like the Teles Pires, Juruena
and Jamanxim rivers, are more related to Xingu and Tocantins rivers than to the lower
portion of the Tapajós River. Due to the expansion of agricultural activities, the rio Teles
Pires basin has been suffering environmental degradation. Large forest areas have been
converted to cattle pasture or soybeans farming (Zaiatz et al., 2018). These activities
occur mainly in the middle and high portions of the river basin, which is a transition
zone between Amazonian and Cerrado domains (Ackerly et al., 1989). In addition, in
the last recent decades, several portions of the river suffered with mining activities and
hydroelectric power plants that are changing rapids (habitat of several catfish species) to
lentic environments (Fernandes et al., 2011; Ohara et al., 2017; Lucanus et al., 2021).
We considered the conservation status of Ancistrus luzia as Least Concern (LC)
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based on the substantial number of catalogued specimens collected through the last two
decades. Nevertheless, part of localities of A. luzia were converted from lotic to lentic
environments due to construction of the hydropower plants São Manoel, Teles Pires,
Colíder, and Sinop. They are part of the Amazon’s Tapajós Dam Complex, a plan to
construct a total of 43 dams in the Tapajós basin (Fearnside, 2015). Other dams from this
complex are predicted for the Teles Pires, which would enable the Tapajós-Teles Pires
Water Way, planned to carry soybeans from Mato Grosso State to the Amazon River and
the Atlantic Ocean (DNIT, 2018). This waterway would require additional interventions
in rapids that impede navigation, eliminating A. luzia habitat in large stretches of the
Teles Pires basin. Therefore, further surveys will show how the species will respond to all
these environmental changes.
Comparative material examined. Ancistrus abilhoai Bifi, Pavanelli & Zawadzki, 2009. MZUSP
104116, holotype, 99.3 mm SL, Brazil, Paraná, Lapa, middle rio Iguaçu basin, rio Iguaçu, 25°47’35”S
50°11’59”W. Ancistrus agostinhoi Bifi, Pavanelli & Zawadzki, 2009. MZUSP 104119, paratypes, 2,
70.7–85.1 mm SL, Brazil, Paraná, Foz do Jordão, lower rio Iguaçu basin, rio Jordão, 25°39’12”S
51°58’15”W. Ancistrus aguaboensis Fisch-Muller, Mazzoni & Weber, 2001. MNRJ 20850, holotype,
66.3 mm SL, Brazil, Goiás, Minaçú, córrego Água Boa, small tributary of rio Bonito, a left bank
tributary of the upper rio Tocantins, 10 km from Minaçú on road Minaçú-Campinaçu, 13º35’S
48º14’W, J. L. Costa Novaes, R. Mazzoni, F. Moraes & C. Weber, 1 Oct 1996. Ancistrus alga (Cope,
1872). LBP 22525, 1, rio Marañon, Amazonas, Peru, 04°19’45.9”S 70°00’30.2”W. C. Oliveira, B. F.
Melo, J. M. Marin & G. Aricari, 13 Nov 2016. Ancistrus brevipinnis (Regan, 1904). MNRJ 42578, 27
(10, 41.6–71.47 mm SL), Brazil, Rio Grande do Sul, Caraá, Boco Stream, tributary of rio dos Sinos
at Linha Padre Vieira II, Jacuí basin, 29º48’24”S 50º17’18”W, 8 Feb 2014, P. A. Buckup, R. S. Lima
& G. V. Buckup. UFRGS 5672, 32 (8, 33.8–82.8 mm SL), Brazil, Rio Grande do Sul, Júlio de
Castilhos, Felício stream, about 10 km SSE from Júlio de Castilhos, laguna dos Patos basin,
29°19’6.00”S 53°37’59.01”W, 28 Nov 2000, L. Malabarba, V. Bertaco, M. Azevedo, J. Bastos & C.
Ricken. Ancistrus bolivianus (Steindachner, 1915), MHNG 2653.001, synonym of A. marcapatae
(Regan, 1904). Bolivia, Tiraque, rivière Huayruru, Espiritu Santo, Chapare, Ichilo, Mamoré,
Madeira basin, 17°28’00”S 65°32’60.0”W, F. M. Carvajal, 14 Jul 2004. Ancistrus bufonius
(Valenciennes, 1840). ANSP 182999, 9, Peru, Apurimac, rio Apurimac (Ucayali basin), Cconoc,
WSW of Limatambo near bridge crossing of main road to Abancay, 13°32’34”’S 72°38’19”’W, 13
Jul 2004, M. Sabaj et al. Ancistrus chagresi Eigenmann & Eigenmann, 1889. ROM 93181, 1, 109.9
mm SL, Panama, Colon Province, rio Caimito, 08°56’31.20”N 80°40’11.21”W, 20 Apr 2012, R. J.
Eakins & J. C. Tetreault. Ancistrus centrolepis. BMNH 1910.7.11.122, paralectotype, female, 148.3
mm SL, Colombia, rio San Juan. Ancistrus cirrhosus (Valenciennes, 1836). CAS-SU 31597, 1, 96.7
mm SL, Argentina, Buenos Aires, La Plata basin. Ancistrus claro. MCP 28667, holotype, male, 64.5
mm SL, Brazil, Mato Grosso, rio Claro, above the bridge, in the direction of Chapada dos Guimaraes.
MCP 28668, paratypes, 9 (3, 41.29–61.69 mm SL), same data as holotype. Ancistrus
cryptophthalmusReis, 1987. MZUSP 28809, holotype, 53.6 mm SL, Brazil, Goiás, São Domingos,
Caverna Passa Três (about 300 m into cave), rio São Vicente System, 1980, Clube Alpino Paulista
leg. Ancistrus cuiabaeKnaack, 1999. MCP 28671, holotype, male, 108.5 mm SL, Brazil, Mato Grosso,
Pantanal, 36 km southeast of Poconé, in a permanent remnant water of rio Bento Gomes, Paraguai
basin. MCP 28672, paratypes, 9 (4, 54–82.1 mm SL), same data as holotype. Ancistrus
falconensisTaphorn, Armbruster & Rodríguez-Olarte, 2010. ANSP 189316, paratypes, 2, 116.0–
92.7 mm SL. Falcón, El Hueque River, 11º09’41.4”N 69º33’24.9”W, at bridge on highway from
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Churuguara to Coro, 19 Oct 2005. D. Taphorn, D. Rodríguez Olarte, J. Coronel, A. Amaro & H.
Rivera. Ancistrus formosoSabino & Trajano, 1997. MZUSP 51836, holotype, female, 71.3 mm SL,
Brazil, Mato Grosso do Sul, Bonito, Buraco do Ducho cave, Serra da Bodoquena, 21º08’S 56º28’W.
Ancistrus galaniPérez & Viloria, 1994. MCP 15634, paratype, female, 55.4 mm SL, Venezuela, Zulia,
Sierra de Perijá, Río Socuy, Cueva de Los Laureles (Zu. 31), 10º45’04”N 72º27’42”W, 25 Mar 1991,
A. Viloria, J. Lagarde. Ancistrus jataiensisFisch-Muller, Cardoso, da Silva & Bertaco, 2005. MCP
35244, holotype, male, 52.7 mm SL, Brazil, Goiás, Mambaí, córrego Jataí, tributary of the rio
Vermelho, 14°29’S 46°6’W, rio Tocantins basin, Centro de Biologia Aquática - UCG, 8 Sep 2002.
Ancistrus karajasde Oliveira, Rapp Py-Daniel, Zawadzki & Zuanon, 2016.NUP 14587, paratype,
1, 34.7 mm SL, rio Parauapebas, Igarapé Alemão, Floresta Nacional de Carajás, 06°00’34”S
50°35’08”W, G. M. dos Santos, 17 Sep 2008. Ancistrus kellerae de Souza, Taphorn & Armbruster,
2019. AUM 62849, paratypes, 3 (1, 55.0 mm SL), Guyana, Region 8 (Potaro/Siparuni), Potaro River
drainage, Kuribrong River, in rapids at Grass Shoals, 05°24’28”N 59°31’54”W, 12 Mar 2014 J.
Armbruster, D. Werneke, E. Liverpool, D. Fernandes & D. Taphorn. Ancistrus krenakarore. NUP
14585, paratypes, 2, 36.1–38.9 mm SL, Brazil, Pará, Rurópolis, rio Itapacurá, right bank tributary of
rio Tapajós, 04°36’20”S 55°30’41”W, F. Ribeiro & W. Pedroza, 9 Sep 2009. Ancistrus leoni de
Souza, Taphorn & Armbruster, 2019. AUM 43665, paratypes, 5 (4, 44.9–49.3 mm SL), Casiquiare
River, left bank upstream from mouth of Siapa River, 02°09’21”S 66°27’50”W, 19–22 Mar 2005, N.
Lujan, M. Arce, T. Wesley & G. Santaella. Ancistrus leucostictus. BMNH 1864.1.21.85, 1, 48.6 mm
SL, holotype of Chaetostomus leucostictus Günther, 1864. Essequibo River, Guyana. Ancistrus
lithurgicusEigenmann, 1912. BMNH 1911.10.31.107–108, 1, 35.1 mm SL, paratype, Essequibo
River, Guyana. Ancistrus macrophthalmus AUM 42105, 5 (4, 74.8–59.9 mm SL), Venezuela, Rio
Orinoco, 50 km of San Fernando de Atabapo Co., Amazonas, Venezuela, 03°58’2.32”N
67°15’12.49”W, 3 Mar 2005, N. K. Lujan, D. C. Werneke, M. H. Sabaj & M. Arce. Ancistrus
marcapatae. 1902.5.29.211, 1, 76.8 mm SL, holotype of Chaetostomus marcapatae Regan, 1904.
Marcapata Valley, eastern Peru. Ancistrus maximusde Oliveira, Zuanon, Zawadzki & Rapp Py-
Daniel, 2015, NUP 14588, paratype, 1, 153.3 mm SL, Brazil, Roraima, Rorainópolis, Macoari
stream, tributary to right side of rio Branco, 01°09’12.1”S 61°50’40.8”W, 2 Nov 2005, A. Negrão
da Silva & M. L. Picanço. Ancistrus minutus Fisch-Muller, Mazzoni & Weber, 2001. MNRJ 20851,
holotype, male, 57 mm SL, Brazil, Goiás, Minaçú, córrego Batéias, a left bank tributary of the upper
rio Tocantins, 13º49’S 48º20’W, J. L. Costa Novaes, R. Mazzoni, F. Moraes & C. Weber, 5 Oct
1996. Ancistrus melas Eigenmann, 1916. FMNH 58339, holotype, 73.6 mm SL, synonym of Ancistrus
centrolepis, Colombia, Condoto, 05º05’40”N 76º39’02”W. Ancistrus montanus (Regan, 1904), CAS-
ICH 77039, 4, 54.9–53.5 mm SL, Bolivia, La Paz, Tumupasa, 30 miles northwest of Rurrenabaque,
Dec 1921, N. E. Pearson. Ancistrus mullerae Bifi, Pavanelli & Zawadzki, 2009. MCP 22577,
paratypes, 8 of 16, 52.4–64.4 mm SL, Catanduvas, stream at PR 477 road between Catanduvas and
Três Barras do Paraná, 25°13’59”S 53°09’42”W. Ancistrus multispinis (Regan, 1912). MNRJ 1078,
70 (30, 44.5–106.7 mm SL), Brazil, Santa Catarina, Hanse (today county of Corupa), rio Humboldt,
tributary of Itapocu river, Ehrhardt. Ancistrus nudiceps (Müller & Troschel, 1849). AUM 48095 (1,
81.8 mm SL), Takutu River, N of Sand Creek, rio Branco, rio Negro, Amazon basin, Guyana,
02°57’29”N 59°57’33”W, 15 Nov 2007, L. S. de Souza, D. C. Taphorn, J. N. Baskin, T. Geerinckx
& J. L. Hwan. Ancistrus occloi Eigenmann, 1928. CAS-ICH 71818, paratype, male, 1, 87.4 mm SL,
Peru, rio Urubamba (rio Santa Ana), Ollantayatambo Village, Incaic ruins, 22 Nov 1918, C. H.
Eigenmann. Ancistrus parecis, MCP 35570, holotype, male, 55.9 mm SL, Brazil, Mato Grosso,
Campos de Júlio, rio Formiga tributary of rio Juruena, upper rio Tapajós basin, on the road BR-364
(MT-235), between Campos de Júlio and Sapezal, 13°41’01”S 59°12’11”W, 13 Jul 2004, P.
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Emanuel B. Neuhaus, Marcelo R. Britto, José Luís O. Birindelli and Leandro M. Sousa
Lehmann, V. A. Bertaco, J. F. P. Silva & F. Langeani. Ancistrus patronus de Souza, Taphorn &
Armbruster, 2019. AUM 43868, paratype, 1, 79.4 mm SL, Caño Soromoni, 11.8 km E of La
Esmeralda, 03°11’38”N 65°39’07”W, 26 Mar 2005, N. Lujan, M. Arce-Hernández, L. Richmond,
B. Grant & E. Wesley. Ancistrus piraretaMuller, 1989. MCP 13704, paratypes, 2, 71.3–77.9 mm SL,
tributary of Río Tebicuary-mi, 25°30’S 56°55’W, Salto Pirareta, South of Piribebuy, Cordillera,
Paraguay. Ancistrus piriformis Muller, 1989. MCP 13703, paratypes, 2, 63.3–65.0 mm SL, Río
Acaray, below the lake of the dam, 25°23’S 54°42’W, Alto Paraná, Paraguay. Ancistrus ranunculus,
MZUSP 47614, paratypes, 2, 50.9–56.3 mm SL, Pará, Cachoeira de Kaituká, rio Xingu, 9 Oct 1990,
L. H. Rapp Py-Daniel & J. Zuanon. Ancistrus reisiFisch-Muller, Cardoso, da Silva & Bertaco, 2005.
MCP 34818, holotype, 60.4 mm SL, Brazil, Goiás, Mambaí, córrego das Dores, tributary of the rio
Vermelho, 14°29’S 46°06’W, rio Tocantins basin, 15 Dec 2002, Centro de Biologia Aquática –
UCG. Ancistrus saudades de Souza, Taphorn & Armbruster, 2019. AUM 48283, paratypes, 32 (2,
65.0–73.45 mm SL), Rupununi, Takutu River drainage, Moco-Moco Creek at Moco-Moco
hydropower station, 18.8 km SE of Lethem, 03°17’47.87”N 59°38’42.25”W, 13 Nov 2007, L. de
Souza, D. Taphorn, J. Baskin, T. Geerinckx & J. Hawn. AUM 67055, paratypes, (5, not measured),
Tumong Creek, left-hand tributary of Ireng River, 04°42’50”N 60°01’20”W, 3 Jan 2016, N. Lujan,
J. Armbruster, D. Werneke & M. Ram. Ancistrus tamboensis Fowler, 1945, MUSM 47882, 1, 83.3
mm SL, Peru, Rio Urubamba, 10°41’34.44”S 73°13’21.87”W. Ancistrus taunayiMiranda Ribeiro,
1918. MZUSP 975, lectotype, rio Lageado, Itaqui, Rio Grande do Sul, Brazil. Ancistrus tolima
Taphorn, Armbruster, Villa-Navarro & Ray, 2013. AUM 54491, paratype, Colombia, Rio
Magdalena drainage, Quebrada El Pescado, 03°35’57.50”N 74°51’16.40”W, vereda San Pablo,
Dolores, departamento de Tolima, Colombia. Ancistrus tombador. MCP 33000, holotype, Brazil,
Mato Grosso, Porto dos Gaúchos, igarapé Ribeirão Preto, on the road MT-338, about 26 km SE
from Porto dos Gaúchos, 11°39’27”S 57°12’7”W, a tributary of rio Arinos, upper rio Tapajós basin,
19 Jan 2002, R. E. Reis, L.R. Malabarba, E. H. Pereira, V. A. Bertaco & A. R. Cardoso. Ancistrus
triradiatusEigenmann, 1918. AUM 36554, 3, 50.8–86.2 mm SL, Venezuela, Estado Bolívar, Rio
Caroní – Rio Orinoco Drainage, Río Claro, 50.5 km SE of Ciudad Bolívar, 07°55’24.89”N
63°06’55.01”W, 10 Jun 2003, J. W. Armbruster, T. P. Pera, N. K. Lujan & O. Léon. Ancistrus
verecundusFisch-Muller, Cardoso, da Silva, Bertaco, 2005. MCP 35572, holotype, male, 52.2 mm
SL, Brazil, Rondônia, Vilhena, igarapé Piracolina, about 6 km W of Vilhena, on the road BR-364,
upper rio Madeira basin, 12°43’33”S 60°11’34”W, 14 Jul 2004, R. E. Reis, P. A. Buckup, A. R.
Cardoso & E. H. Pereira.
ACKNOWLEDGMENTS
We are grateful to Mário C. C. de Pinna and Michel Gianeti (MZUSP) for the loan
of specimens and for Jonathan W. Armbruster for providing QGIS files for the map.
EBN is supported by Proex/Capes (Proc. 88882.183270/2018–01). We thank Murilo
Bastos (MNRJ) for information about Luzia in the Biological Anthropology collection
and help with etymology. MRB is supported by grants from the Conselho Nacional
de Desenvolvimento Científico e Tecnológico (CNPq, process #309285/2018–
6305955/2015–2) and Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado
do Rio de Janeiro (FAPERJ, grant #200.103/2019). LMS received a CNPq Productivity
Grant #309815/2017–7 and #311148/2020–4, and JLB received CNPq Productivity Grant
#302872/2018–3. We also thank the Catfish Study Group for supporting the acquisition
of the digital camera used to take the photos of the preserved specimens.
Neotropical Ichthyology, 20(1):e210129, 2022
20/21 ni.bio.br | scielo.br/ni
New Ancistrus from Tapajós and Xingu
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This is an open access article under the terms of the
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AUTHORS’ CONTRIBUTION
Emanuel B. Neuhaus: Conceptualization, Data curation, Formal analysis, Investigation, Methodology,
Project administration, Resources, Supervision, Validation, Writing-original draft, Writing-review and
editing.
Marcelo R. Britto: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation,
Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing-original
draft, Writing-review and editing.
José Luís O. Birindelli: Conceptualization, Data curation, Formal analysis, Investigation, Methodology,
Project administration, Resources, Supervision, Validation, Visualization, Writing-original draft, Writing-
review and editing.
Leandro M. Sousa: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project
administration, Resources, Supervision, Validation, Visualization, Writing-original draft, Writing-review
and editing.
ETHICAL STATEMENT
Not applicable.
COMPETING INTERESTS
The authors declare no competing interests.
HOW TO CITE THIS ARTICLE
Neuhaus EB, Britto MR, Birindelli JLO, Sousa LM. A new species of Ancistrus
(Siluriformes: Loricariidae) from Tapajós and Xingu basins, Brazil. Neotrop Ichthyol. 2022;
20(1):e210129. https://doi.org/10.1590/1982-0224-2021-0129
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Two new species of Ancistrus are described from Amazon basin: A. krenakarore from rio Itapacura, a tributary of the right margin of the lower rio Tapajós drainage; and A. karajas from small headwater streams of rio Parauape- bas, a tributary of left margin of lower rio Tocantins drainage, both from Para State, Brazil. The two new species differ from all congeners except A. jataiensis, A. parecis, A. reisi, A. tolima, A. tombador, A. verecundus and A. veri- caucanus by the absense or vestigial adipose fin (vs. presence of a fully-developed fin). The new species differ from all congeners without adipose fin by the presence of only one preadipose plate and by a combination of morphometric characters; and differ from each other by color pattern.
Article
The genus Otocinclus Cope (1872) of the siluriform family Loricariidae is diagnosed as monophyletic on the basis of shared derived characters of the cranial and hyobranchial skeleton, dorsal gill arch musculature, and gut. Otocinclus are relatively small herbivorous catfishes restricted to small streams and quiet slow-flowing margins of larger rivers, most frequently living in close association with aquatic macrophytes and terrestrial marginal grasses extending into the water column. Otocinclus species share a novel modification of the distal esophageal wall which is developed into an accessory blind diverticulum that may function in aerial respiration and for providing additional modulatory positive buoyancy for remaining in the upper water column at stream margins. Otocinclus has no junior synonyms, however several nominal species originally described in Otocinclus are here formally re-assigned to other genera in the subfamily Hypoptopomatinae. Otocinclus cephalacanthus Ribeiro 1911, O. depressicauda Ribeiro 1918, O. francirochai Ihering 1928, O. laevior Cope 1894, O. leptochilus Cope 1894, O. maculipinnis Regan 1904, O. nigricauda Boulenger 1891, and O. paulinus Regan 1908 are all placed in the genus Microlepidogaster Eigenmann & Eigenmann 1889; O. obtusos Ribeiro 1911 was placed in Pseudotothyris Britski & Garavello 1984; the genus Nannoptopoma Schaefer 1996 was erected for O. spectabilis Eigenmann 1914 in the tribe Hypoptopomatini; O. gibbosus Ribeiro 1908 is removed from Otocinclus, yet remains of undetermined generic status. Thirteen species are recognized in Otocinclus: O. affinis Steindachner 1877 of the lower Paraná/Paraguay and Uruguay basins and coastal streams of southeastern Brazil; O. bororo n. sp. of the upper Río Paraguay; O. caxarari n. sp. of the middle Río Guaporé/Mamoré system; O. flexilis Cope 1894 of the lower Paraná/Paraguay and Uruguay basins and coastal streams of southeastern Brazil; O. hasemani Steindachner 1915 of northern Brazil; O. hoppei Ribeiro 1939 of the upper Amazon, Tocantins and Paraguay basins and coastal streams of northeastern Brazil; O. huaorani n. sp. of the upper Amazon and Orinoco basins; O. macrospilus Eigenmann & Allen 1942 of the upper Amazon basin of Colombia, Ecuador, and Peru; O. mariae Fowler 1940 of the lower Amazon, upper Madeira and Paraguay basins; O. mura n. sp. of the middle Amazon River; O. vestitus Cope 1872 of the upper Amazon and lower Paraná basins; O. vittatus Regan 1904 of the Amazon, Orinoco, Paraná/Paraguay, and Tocantins basins; and O. xakriaba n. sp. of the rio São Fransisco basin. Two species are placed in synonymy: Otocinclus arnoldi Regan 1909 and O. fimbriatus Cope 1894 are junior synonyms of O. flexilis. Keys to the species of Otocinclus and genera of the Hypoptopomatinae are provided. A descriptive treatment of the osteology and cranial myology is provided for O. vittatus. Detailed analysis of meristic and morphometric variation based on geometric morphometric procedures is provided for the phenetically similar species pairs O. mariae and O. vittatus, O. bororo and O. huaorani in an a posteriori evaluation of separate species status. The phylogenetic relationships among Otocinclus species, and the phylogenetic position of Otocinclus among genera of the Hypoptopomatinae, are determined based on analysis of 27 morphological features using cladistic parsimony. Monophyly of Otocinclus was confirmed; within Otocinclus, a clade comprised of O. affinis and O. flexilis is the sister-group to the remainder of the genus. Within that latter clade, O. hasemani and O. xakriaba are the first and second-level sister-groups to the remainder of the genus, within which relationships among species are not fully resolved with available data. The phylogenetic biogeography of Otocinclus is informative regarding the historical relationships among major river drainage basins, particularly of those river systems of the Brazilian Shield. A biogeographic hypothesis is proposed based on the area cladogram derived from the species-level phylogenetic relationships, which suggests successive vicariance and speciation in the non-Amazonian regions of endemism of southeastern and eastern South America, followed by speciation and dispersal within the Amazon, Orinoco and upper Paraguay basins. The pattern of vicariance revealed by the Otocinclus species-level phylogeny is congruent with the geologic history of the major river drainage basins of the Brazilian Shield. This result suggests that, for Otocinclus and perhaps other loricariid catfishes, much of their generic and species-level diversification occurred prior to the formation of the Amazon basin.