Probolodus heterostomus
Probolodus heterostomus Eigenmann, 1911
Also calledLambari (por)
First described in: Eigenmann, C. H. 1911. New characins in the collection of the Carnegie Museum. Annals of the Carnegie Museum 8(1): 164-181.
Deuterodon heterostomus is a small species of characin endemic to a large river system in southeast Brazil. It was originally the only member of the genus Probolodus, but Probolodus is now considered obsolete, synonymized with Deuterodon. Much like other members of Deuterodon, and like some fish in related genera, D. heterostomus is a small, silvery fish with fins in some combination of red and clear. It has a defined humeral spot that can be used for identification.
Its diet was not well-known until a 1970 study that classified it as a voracious lepidophage, preying on other fish species for their scales. Most of its food is sourced from related fishes such as Psalidodon fasciatus, a cryptic species to which D. heterostomus bears a strong visual resemblance. This resemblance has been proposed to be a form of mimicry, allowing D. heterostomus to easily approach its prey.
Descriptions from checklists and floras indexed by GBIF
description
1. Mamilliform teeth outside mouth (120): (0> 1) present. Paralleled in nodes 218 and 277. 2. Number of rows of premaxillary teeth (122): (1> 0) one. Paralleled in node 195 and in Aulixidens eugeniae, Carlana eigenmanni, Carnegiella strigata, Grundulus cochae, Odontostoechus lethostigmus, Paracheirodon axelrodi, and Piabucus melanostomus. 3. Number of teeth in inner premaxillary row (129): (1> 0) four or fewer. Paralleled in node 198 and in Markiana nigripinnis. 4. Posterior extent of ventral process of quadrate (151): (0> 1) falling short of posterior margin of symplectic. Paralleled in the Hyphessobrycon luetkenii clade and Iguanodectinae, in nodes 284, 289, and 298, and in Astyanax mexicanus, A. cf. rutilus, Aulixidens eugeniae, Cyphocharax spilotus, Diapoma speculiferum, Hemiodus cf. thayeria, Metynnis maculatus, Micralestes stormsi, Moenkhausia sanctaefilomenae, Nematocharax venustus, Psellogrammus kennedyi, and Pseudocorynopoma doriae. Some trees: Paralleled in node 302. 5. Posterior margin of cleithrum (234): (0> 1) with concavity ventral to first postcleithrum. Reversal of synapomorphy 4 of node 204. Paralleled in nodes 196 and 289 and in Roeboexodon geryi. 6. Position of v
Phylogeny of the family Characidae (Teleostei: Characiformes): from characters to taxonomy
description
Description. Morphometrics of holotype and non-type specimens presented in Table 1. Body moderately compressed and deep, less so in individuals of less than 150 mm SL, greatest body depth within region delimited anteriorly by vertical through insertion of pelvic fin and posteriorly by vertical through origin of dorsal fin. Average body depth variable among population samples, but with broad overlap in ranges among examined samples. Dorsal profile of head distinctly convex from margin of upper lip to vertical through posterior nostril, straight to very slightly convex from latter point to tip of supraoccipital spine. Dorsal profile of body moderately convex from tip of supraoccipital spine to origin of dorsal fin, straight and posteroventrally-slanted along base of dorsal fin, straight to slightly convex from posterior terminus of base of dorsal fin to adipose fin, and slightly concave along caudal peduncle. Broad middorsal ridge present along predorsal region of body, with ridge less obvious anteriorly. Dorsal region of body between posterior terminus of dorsal fin and adipose fin transversely rounded overall, but slightly flattened middorsally in some individuals. Ventral profile
Taxonomy of Probolodus Eigenmann, 1911 (Characiformes: Characidae) with description of two new species, and comments about the phylogenetic relationships and biogeography of the genus
diagnosis
Diagnosis. Probolodus heterostomus differs from its two congeners, P. oyakawai (new species) and P. sazimai (new species) by the following attributes: 45 - 56 perforated scales on the lateral line (vs. 41 - 43 and 36 - 43 perforated scales, respectively); 18 - 21 scale series around the caudal peduncle (vs. 14 - 16 scale series around the caudal peduncle); symplectic with bone projection posteroventrally developed (vs. sympletic without bone projection) (Fig. 4 a); process extending posteriorly along the dorsal margin of the hyomandibular (vs. hyomandibular with flat margin, without process) (Fig. 4 a), and anterior portion of urohyal not bifurcated, with central orifice (vs. anterior portion of urohyal bifurcated) (Fig. 4 b).
Taxonomy of Probolodus Eigenmann, 1911 (Characiformes: Characidae) with description of two new species, and comments about the phylogenetic relationships and biogeography of the genus
discussion
Remarks. Roberts (1970) examining stomach contents of some lepidophagous characids, such as Catoprion, Exodon, Roeboides, and Roeboexodon, was the first author to observe a large number of scales in the stomachs of specimens of Probolodus heterostomus and commented on the absence, until then, of knowledge about the relationships among the lepidophagous genera aforementioned (see more details about the lepidophagous taxa in Sazima, 1977; Géry, 1980; Sazima & Uieda, 1980; Sazima & Machado, 1982; Sazima, 1983; Vari, 1986; Janovetz, 2005). Still, Roberts (1970) considered the genus P. heterostomus very similar to the tetras of the genus Astyanax. Therefore, Géry (1977) based in Eigenmann (1911, 1915) and Roberts (1970), considered P. heterostomus morphologically very similar to the tetras of the genus Astyanax, especially A. fasciatus, but both with different dentitions. According to the cited author, the tricuspidate teeth of P. heterostomus are few in number and directed outward, especially on the prominent dentary, enabling it to remove rows of scales of other fishes, possibly from the bottom up. However, Sazima (1977) suggested that A. fasciatus is the main prey of P. heterostomus,
Taxonomy of Probolodus Eigenmann, 1911 (Characiformes: Characidae) with description of two new species, and comments about the phylogenetic relationships and biogeography of the genus
From Wikipedia (CC BY-SA), quoted section by section
Description
Deuterodon heterostomus reaches a maximum of roughly 10 cm (3.9 in) SL (standard length, without the tail fin included). Most larger specimens are between 6 cm (2.4 in) and 8 cm (3.1 in) SL. The body is somewhat compressed and deep; this is more evident in smaller specimens, and body depth can vary between populations, though there is significant overlap between those located near each other. There are 45–56 scales in the lateral line, with 8–10 scale rows above it and 7–10 rows below. There are 11 total rays in the dorsal fin, 26–34 rays in the anal fin (rarely 35 or 36), 12–14 rays in the pectoral fin, 6–9 rays in the ventral fin (most often 8), and 19 rays in the caudal fin. As early as the time of its description, D. heterostomus was noted to closely resemble Astyanax fasciatus, a cryptic species now known as Psalidodon fasciatus. Features include a silver base color and reddish fins, with the exception of the ventral and pectoral fins, which are clear. There is a large humeral spot, vertically elongated, that can be anywhere above the region between the 3rd and 5th scale of the lateral line. There is another spot on the caudal peduncle that continues onto the fin-rays in younger specimens; the ray pigmentation fades somewhat in adults.
Sexual dimorphism. Females are the larger of the two sexes, averaging 12 cm (4.7 in) longer than males when fully grown. …
Range & habitat
Deuterodon heterostomus can be found in the coastal river basins of southeastern Brazil. More specifically, it is known to occur in tributaries of the rio Paraíba do Sul basin. The region generally has a neutral water pH, ranging from 6 to 8, and various sites tend to have similar water temperatures, ranging from 22 to 25 °C (72 to 77 °F).
Diet. Deuterodon heterostomus is an omnivore, but most of its diet consists of the scales of other fish - a habit known as lepidophagy. This was first observed in a study of stomach contents from 1970; in 50% of examined specimens therein, scales were the only food item found in the stomach. Other specimens had eaten small seeds, microcrustaceans, and insects (plus insect larvae). Ichthyologist Ivan Sazima proposed in 1977 that the strong resemblance between D. heterostomus and P. fasciatus is a form of aggressive mimicry; because D. heterostomus looks like P. fasciatus, specimens of the latter are more likely to let the former get close, which would result in an easy source of scales for food.
In human culture
The genus name "Deuterodon" originates in Greek. Its roots are "deuteros", which means "second" or "repeated", and "odon", which means "tooth"; this is in reference to the similarity of all teeth in the lower jaw. The species name "heterostomus" is also from Greek, where "hetero" means "different" and "stomus" means "hole" or "mouth"; the original description noted peculiarity in the way the teeth point outwards.
Where it has been recorded
Recorded sightings
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geo-referenced records in GBIF, from museums, herbaria and field observers.
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In the stacks
Searching the stacks…
Every page naming Probolodus heterostomus in the Biodiversity Heritage Library →
From the GBIF Backbone Taxonomy and occurrence records (GBIF.org), with Wikipedia and the Source Library. GBIF species 2352452.