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Hypostomus velhomonge

L078

L077

Hypostomus faveolus

Abstract
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.

Jools wrote: ↑18 Apr 2022, 13:22Pretty sure L078 is one of the species mentioned in the paper, but can't see the plates. Given smaller than eye sized spots on the head, is the longer lower caudal lobe the key feature to makes L078 = this new species?

Jools

Jools wrote: ↑19 Apr 2022, 16:29Sorry, I meant plates in terms of the armour plates on the fish as mentioned in the key. L078 is something of a phantom in the hobby, but going on what we know, I would be inclined to make L078 = Hypostomus velhomonge. Interested in others views / check my assumptions.

Jools

Acanthicus wrote: ↑23 Apr 2022, 21:08Hi,

I think L 78 is the fish mentioned as H. aff. pusarum (fig.10) in the paper. The eye size of H. aff. pusarum matches L 78 better than H. velhomonge does. Plus, in DATZ Rainer mentioned the elongated caudal lobes, which are also present in the specimen of H. aff. pusarum. Obviously they might be broken in the specimen shown as H. velhomonge, but to me the fin doesn't look like it should have elongated caudal lobes.

The whole body of H. velhomonge seems more compressed than what I imagine L 78 would look like on comparable pictures. The mouth is very wide, larger than in H. aff. pusarum. Based on the one specimen presented by DATZ my feeling is that L 78 doesn't have such a large oral disk.

About the missing L 77: I wondered too at first, but read the DATZ presentation again and there is no accurate locality given for L 77. it was just imported with some Geophagus sp. from the Parnaiba area, but who knows where exactly it was collected. Maybe it was not within the "Maranhão-Piauí ecoregion", which the paper is about.

Key to the species of

Hypostomus

from Maranhão-Piauí ecoregion

1a. Dark vermiculated color marks

Hypostomus vaillanti

(Fig. 7)

1b. Rounded dark spots 2

2a. Premaxilla and dentary, each with more than 100 teeth 3

2b. Premaxilla and dentary each with less than 100 teeth 4

3a. Anteromedial region covered by plates and odontodes and ventral lobe of caudal-fin much longer than dorsal lobe

Hypostomus johnii

(Fig.

3b. Anteromedial region deprived of plates and odontodes and the caudal-fin ventral lobe slightly longer than dorsal lobe

Hypostomus velhomonge

(Fig. 3)

4a. Body and head covered with spots usually smaller than the diameter of the eye

Hypostomus pusarum

(Fig. 9)

4b. Body and head covered with spots usually larger or the same size as the diameter of the eye, conspicuous and spaced

Hypostomus aff. pusarum

(Fig. 10)