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| Hypostomus velhomonge Lustosa-Costa, Ramos, Zawadzki & Lima, 2022 |
The species of Hypostomus from the Parnaíba River basin were reviewed through molecular and morphological analysis. Five species were found in the basin, including a new species herein described. The distribution of H. pusarum was expanded to this basin, and a closely related species was recorded (H. aff. pusarum), also the presence of H. johnii and H. vaillanti was confirmed. The new species is distinguished from most congeners by its large number of premaxillary and dentary teeth, a wide dental angle of 115° to 135°, presence of a rounded dark spots on a lighter background and anteromedial region of the abdomen depleted of plaques (vs. anteromedial region of the abdomen covered by platelets and odontodes in H. johnii, H. pusarum, H. aff. pusarum and H. vaillanti). Furthermore, an identification key of the species from the Maranhão-Piauí ecoregion and maps with the geographic distribution of these species are presented. The species of Hypostomus in the Parnaíba River basin have different geographic distributions, suggesting different niches or geographical barriers, providing an opportunity for ecological and evolutionary studies.
Keywords: Cryptic diversity, DNA Barcode, Identification key, Integrative taxonomy, Maranhão-Piauí ecoregion.
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| Hypostomus velhomonge, UFPB 9565, holotype, 118.0 mm SL, rio Balsas, tributary of Parnaíba River, Maranhão State, Brazil. |
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| Hypostomus velhomonge, color in life, UFPB 9566, paratype, 88.0 mm SL, with non-deposited material. Parnaíba River, Santa Filomena, Piauí, Brazil. |
Hypostomus velhomonge, new species
Hypostomus sp. 2. —Ramos et al., 2014 (listed, ichthyofauna of the Parnaíba River).
—Silva et al., 2015 (listed, ichthyofauna of the Gurgueia River).
—Lima et al., 2017 (listed, ichthyofauna of the Caatinga).
Diagnosis. Hypostomus velhomonge differs from congeners, except Hypostomus alatus Castelnau, 1855, H. arecuta Cardoso, Almirón, Casciotta, Aichino, Lizarralde & Montoya-Burgos, 2012, H. bolivianus (Pearson 1924), H. denticulatus Zawadzki, Weber & Pavanelli, 2008, H. francisci (Lütken, 1874), H. freirei Penido, Pessali & Zawadzki, 2021, H. isbrueckeri Reis, Weber & Malabarba, 1990, H. jaguar Zanata, Sardeiro & Zawadzki, 2013, H. kuarup Zawadzki, Birindelli & Lima, 2012, H. leucophaeus Zanata & Pitanga, 2016, H. luteomaculatus (Devincenzi, 1942), H. meleagris (Marini, Nichols & LaMonte 1933), H. multidens Jerep, Shibatta & Zawadzki, 2007, H. mutucae Knaack, 1999, H. myersi (Gosline, 1947), H. Paulinus (Ihering, 1905), H. regani (Ihering, 1905), H. strigaticeps (Regan, 1908), H. ternetzi (Boulenger, 1895), H. unae (Steindachner, 1878), H. uruguayensis Reis, Weber & Malabarba, 1990, and H. yaku Martins, Langeani & Zawadzki, 2014by having high number of teeth on premaxillary (62–95, mode 73) and dentary (64–110, mode 76) (vs. smaller number of teeth on both premaxillary and dentary, rarely more than 50). Hypostomus velhomonge differs from H. alatus, H. arecuta, H. francisci, H. luteomaculatus, H. meleagris, H. multidens, H. myersi, H. regani, H. sertanejo and H. strigaticeps by having dark spots over body and fins (vs. pale spots). The new species is distinguished from H. bolivianus, H. denticulatus, H. freirei, H. isbrueckeri, H. jaguar, H. johnii, H. ternetzi, H. uruguayensis and H. leucophaeus by having ventral region of head and anteromedial region of abdomen naked, even on larger specimens (vs. ventral region of head and anteromedial region of abdomen covered by plates at least on larger specimens). Additionally, H. velhomonge differs from H. bolivianus by having bicuspid teeth (vs. unicuspid teeth); from H. denticulatus by having teeth with asymmetric cusps (vs. teeth with symmetrical cusps); from H. isbrueckeri by having homogeneous caudal-fin ground color, without marks (vs. yellow band on distal caudal-fin margin in mature males); from H. jaguar by possessing faint, small dark spots on head, the spots, smaller than the pupil (vs. head covered with large spots, larger than the pupil); from H. johnii by presenting the caudal-fin ventral lobe slightly longer than dorsal lobe (vs. ventral lobe of caudal-fin much longer than dorsal lobe); from H. ternetzi by having roughly flat interorbital and predorsal region (vs. interorbital and predorsal region with strong median keel); from H. unae by having compressed caudal peduncle, its depth larger than its width at adipose-fin origin (vs. rounded caudal peduncle, its depth equal to its width at adipose-fin origin); from H. vaillanti by having ventral region of head and abdomen usually without spots; dark spots present in few specimens (vs. ventral region of head and abdomen with conspicuous spots in the shape of whole or half rings,); from H. uruguayensis by having one predorsal plate bordering supraoccipital (vs. three predorsal plates bordering supraoccipital). The new species can be distinguished from Hypostomus kuarup by having large dark spots on sides of body, spots similar in length to eye diameter (vs. small dark spots, similar in length to pupil diameter); from H. mutucae by having narrower dentaries, each dentary length about half interorbital width (vs. similar in length to interobital width; see figs. in p. 103 and 106 of Knaack, 1999 and fig. 7 in Zawadzki et al., 2012), by having smaller angle between dentaries, from 115° to 135° (vs. from 160° to 170°), and by having round oral disk (vs. clearly transversally elongated); from H. yaku by lacking hypertrophied odontodes on flanks (vs. hipertrophied odontodes on flanks, more developed in mature males).
Geographical distribution. Hypostomus velhomonge is apparently endemic to Parnaíba River basin and, so far, the species has only been found in the upper and middle portions of the basin, restricted to Cerrado areas in the drainage (Fig. 6).
Ecological notes and habitat. Hypostomus velhomonge was recorded in co-occurrence with other loricariids such as H. vaillanti in the Muquém stream, in Barão de Grajaú, Maranhão, with Loricaria parnahybae Steindachner, 1907 and Loricariichthys derbyi Fowler, 1915 in the rio Balsas. All localities where Hypostomus velhomonge were recorded presented riparian forest typical of the Cerrado biome (Fig. 6). The type locality, Balsas River, has clear waters, rocky and sandy substrate and varying amounts of remnants of riparian vegetation.
Etymology. The specific epithet, “velhomonge”, is a reference to the Parnaíba River, commonly known as ‘Velho Monge’ (Old Monk, in English). One of the versions on the origin of this name portrays that a poet called Costa e Silva gave the river the nickname “Velho Monge” because, when seen from the city of Amarante, the confluence of Canindé River with Parnaíba River forms a landscape that, in profile, reminds the silhouette of a monk and whose foam suggests its long beard. A noun in apposition.
Common names. Cari, acari, bodó.
Silvia Yasmin Lustosa-Costa, Telton Pedro Anselmo Ramos, Cláudio Henrique Zawadzki and Sergio Maia Queiroz Lima. 2022. Review of the Armoured Catfish Genus Hypostomus (Siluriformes: Loricariidae) from the Parnaíba River basin, Northeastern Brazil, with Description of A New Species. Neotropical Ichthyology. 20(1); e210126. ni.bio.br/1982-0224-2021-0126/
10.1590/1982-0224-2021-0126
