Article © Sandor Tüllmann, uploaded June 10, 2012.
A group of aquarists spread as wide as the USA, Scotland, England and Germany have been considering this group of butterfly or flounder plecos in co-operation with scientists working in the field. At present these species are placed in Dekeyseria but are also associated with Peckoltia, Zonancistrus and, a long time ago, Ancistrus in the literature. As such, I translated the old (1854) descriptions of three of these species from Kner's paper. To provide some context, this is what Shane Linder wrote as an overview and introduction on the utility of the translation for the group.
"In the aquarium hobby L052 is applied to specimens collected from the Rio Atabapo. When I was living in Colombia (2002-2004) these fish were somewhat uncommon. They were not targeted for collection, but turned up in Bogotá (via Puerto Carreño) as bycatch from collectors after Altum angels and Uaru fernandezyepezi. As bycatch, they commanded very low prices and could be had in Bogotá for under a dollar US. They are now targeted for collection, but still bring low prices. A 19 September 2011 list I have from Bogotá prices them at US $1.80 each 30-50 specimens per box.
L168, which has become associated with Dekeyseria brachyura (Kner, 1854) in the hobby, is reportedly collected in and around the Rio Demini (Rio Negro), and is exported via Manaus. Because of export routes, L052 is seen as a "Colombian" fish and L168 as a "Brazilian" fish by hobbyists. L168 is the more attractive of the two as its pattern (which is nearly identical to that of L052) is typically more contrasting. It also fetches much higher prices.
Both fish are capable of incredible colour and pattern changes that react to the hue of substrate they are placed over and amount of ambient light. This makes the use of colour and pattern almost useless for ID purposes. As has been pointed out, there are several described species that may match up with these species in addition to the commonly applied D. brachyura (Kner, 1854) [Lower Negro River basin, Brazil (Fisch-Muller, 2003)].
D. amazonica Rapp Py-Daniel, 1985: I do not have the description, but it would be worth taking a look at, especially as it is fairly recent (1985). The sp is noted as found primarily above Manaus (Fisch-Muller 2003), which adds to the chances it would be exported for the hobby.
D. picta (Kner, 1854): Lower Negro River basin, Brazil (Fisch-Muller, 2003).
D. pulchra (Steindachner, 1915): Upper Negro and Orinoco rivers and Canal Casiquiare basin, Brazil, Colombia, Venezuela (Fisch-Muller, 2003). "
Translation of original Pages 277 to 281.
5. Species: Anc. pictus m. Plate IV, Fig. 2
Back and sides keeled, head coarsely plated on the rim, with only the middle of the snout being naked; Lower yaws shorter than median yaws, but with longer teeth, caudal fin truncated with the lower part longer than the upper.
While the above species of this genus all lack keeled plates along the torso and may be grouped according to this characteristic, this and the following two species do have such keeled plates and may therefore be assigned to a second group. They additionally share the form of odontodes on the gill covers as well as the ray count of the anal fin (A. 1/5), where in this respect the above mentioned species, A. mystacinus, may be considered as a link between these two species groups.
The body is comparatively broad and depressed; the head length is ⅓ of the body length and approaches the maximum breadth, while the maximum height of the head is 2 and ½ times lower than the maximum overall height. The circular, large eyes, the diameter of which is almost 1/5 of the head length, are very inclined and 2 and ½ to 3 diameters away from the middle of the snout, 1 and ½ diameters apart from each other and just as far away from the back temple plate. The nostrils are quite small, their longer diameter is only ½ of the eye diameter, and they are apart from each other by the same length. They are also ½ eye diameter below the forward rim of the eyes. The whole upper head is, with the exception of the tip of the snout, plated; the coarse plates of the rim, however, arch around the naked spot from below and completely cover the outer part of the forward rim of the mouth. All head plates lack keels, only one blunt keel is found starting from the forward end of the eyes, passing below the nostrils, which makes the middle of the snout, where they unite, appear quite domed. All head plates appear uneven due to fine, coarse sheer lines. The interoperculum carries a bundle of about 20 thin odontodes, where the last and longest (⅓ of the head length) extends beyond the basis of the pectoral fin. With respect to size, form and so forth these odontodes completely resemble those of the above species. The rim plates of the heads have a velvety look to them due to extremely short, fine odontodes. The sides of the trunk are covered with three sharp, toothed keels; several plates even carry a second keel. The median plates forward of the first dorsal are smooth, while the plates beyond the first dorsal carry an additional, fourth keel which is suspended under the second dorsal, but continues after this second dorsal and remains obvious until the caudal fin. Along the ordinary lateral line one can count a row of 23-24 plates. The characteristics of the head channels are obvious until below the eyes. All body plates are, just like the ones on the head, coarse, while their ends do not appear to be toothed. The belly is naked down to the anal area; from there on one finds a median row of 16 plates down to the caudal fin.
The lower, large lip is even and at its forward area densely covered with bulbous partly rounded papillae; the corner barbles are short and thin, but obvious. The teeth of both yaws are thin as hairs and have, as usual, brown, forked tips, just like Hyp. barbatus; each upper mandible carries more than 30 teeth, the lower yaws have fewer teeth because they are shorter and less developed. Its middle teeth are, however, longer than those of the upper yaws. D. 1/7, A. 1/5, . . . C, 15-16.
The first dorsal is a little bit longer than high and its first ray is even shorter than that of the ventral fin, the first ray of the second dorsal is sickle shaped, rather large and strongly compressed. The thick first ray of the pectorals reaches back until about the middle of the ventral and is covered above with long thin odontodes which resemble those of the interoperculum, also being brown with forward pointing tips. [Footnote: Two of the larger specimen only have short odontodes; Whether this represents a sexual dimorphism cannot be decided due to lacking intestines.] The first ray of the ventrals is shorter than the following, which are branched; the soft rays of this fin extend to the middle of the anal fin. This anal fin originates exactly at the terminus of the first dorsal fin and is strongly developed, almost half as long as the pectorals. The truncated caudal is not forked, but the lower lobe is longer than the upper.
The base colour of the back is light brown; the upper head is decorated with light yellow spots, which merge behind the back of the head, but also occasionally between the eyes, to a broad, wavy lateral band; such a lateral band is also found between the eyes and the snout. The body is, to the sides of the first dorsal fin, marked with 3-4 unevenly sized, large light spots. In two specimen, these spots also unite to a lateral band; a second row of larger spots of the same colour is found along the lower sides. All light spots on the trunk vary in size and count and occasionally become so blurred into each other that one finds alternating dark and light lateral bands at the caudal peduncle. The first dorsal has three longitudinal dark bands, where the upper and median ones unite to the distal end. Pectoral, ventral and anal fins show similar, but more blurry dark bands, the caudal has only one small stripe in the middle. The rim as well as the origin of the caudal are dark. The naked underside is off-white and without spots. The five specimen of the k. u. k. Museum are from Barra do Rio Negro; the total length of the largest is 5 and 1/3, the smallest one only 2 and ¼ inch [Note by the translator: these are Austrian Inches: one Austrian Inch is 0.02634 meters].
The two smallest specimen show several differences, which are likely cause by the age difference. All plates are only weakly developed, especially those along the lateral lines, where they do not meet at their rims, and the median ones on the back are not yet joined along the middle line. Their coarseness and the odontodes along the side lines are, however, comparatively stronger developed. The odontodes of the interoperculum are short and present in fewer numbers, just like the teeth, due to weaker developed yaws. The first pectoral ray does not extend to the middle of the ventral, and only carries few, short odontodes. With respect to meristics, no difference is found. The coloration deviates in so far as, just like with young trouts, dark and broad lateral bands are present, where the first of those extends on the forward back, the second at the insertion of the dorsal, and the third is found at the end of the dorsal fin, a fourth between first and second dorsal fin, and a fifth is found below the second dorsal fin. The first dorsal is light only along the middle, while basis and rim are dark; the dark bands of the pectorals, ventrals and caudal on the other hand are already well developed, just like the light bands on the head.
6. Species. A. brachyurus m. Plate IV, Fig. 1.
The head is broad, caudal peduncle as well as caudal fin are short, the sides are keeled, teeth in the upper yaws are longer, odontodes on the interoperculum like the species above.
The length of the head amounts to 1/3 of the total body length, just like the species above; the width of the head equals the body's width and the height is only one half of the body width. The eye is large with its diameter being almost 1/5 of the head length; it is three diameters from the tip of the snout and hardly 1 and ½ away from the other eye and the back end of the head. The long diameter of the nostrils is considerably smaller than that of the eyes, is equal to the distance between the nostrils. The nostrils are located before the eyes by one diameter of the nostrils; the distance to the tip of the snout equals two eye diameters. The head is parabolic in shape, with the rim plates being densely covered with short, brown tipped brush like odontodes and overlap on the underside such that only the middle of the snout's tip remains naked. The remaining plates of the head have coarse lines, are not keeled and only the forward rim of the eyes appears to carry eyelashes. The median plate of the back end of the head ends distally in a tip. The very flexible interoperculum carries odontodes very similar to those of Anc. pictus, which are long, thin and amount to 16-20. Shorter ones growing back are visible at the rim of the interoperculum. The largest ones reach back to the humerus, are completely straight and are only very slightly bent at the brownish tip.
The plates of the torso are keeled like those of Anc. pictus, where only the topmost two are only weakly defined at the beginning, and only the lowest keel is clearly present from the very first plate. The keel accompanying the lateral line is the only one that extends to the caudal, while the ones above and below end at the second dorsal. At the lateral line, one finds 23 plates until the caudal. The whole underside is naked until the anal area, and only at the rims of the head the plates tend to overlap. There is a row of 12 plates between anal and caudal fin. 1. D. 1/7, A. 1/5, . . . C. 14.
The first dorsal is considerably longer than high and the distance between the tip of the snout and the first dorsal is as long as the distance between first and second dorsal. It therefore remains well separated from the second dorsal even if it is completely folded back. In this folded state, four plates remain visible. The first pectoral ray is longer than the head and reaches back to half the length of the ventral fin, or, equally put, almost to the anal area. As usual it is covered with long odontodes, the tips of which are arched upwards. Toward the tip of the ray the count as well as length of the odontodes becomes larger. These strongly resemble the odontodes of the interoperculum with respect to form, color, size and so forth. The ventral fins extend to the basis of the anal fin. The insertion of the anal fin is opposite to the end of the dorsal and therefore in the last third of the body length; it is well developed and extends back six bone plates. While the upper tip of the caudal appears bruised and atrophied, and the lower one completely intact, one still finds that even the longest ray of the larger, lower lobe is only as long as the first ray of the dorsal. It is therefore considerably less well developed than in all the other species; it is not forked.
The mouth is regularly shaped and appears scraggy due to pappilae that extend to the tip of the lip. The barbels are very short, the teeth in the lower yaw are longer, and all tips are yellowish. Upper and lower jaw are of the same length, and one may count 20-24 upright teeth on each of them.
Coloration. Back and sides are brown, underside light yellow. One washed out dark, broad spot behind the eyes, and traces of additional spots are found along the back and the caudal peduncle; the dorsal has two light and three dark stripes, the pectoral and ventral fins have comparable dark stripes, the caudal is light in the middle, and basis as well as rim are dark.
Only one specimen in alcohol, 6 inch total length and 1¾ inches broad. Collection locality: Barra do Rio negro.
7. Species: Anc. scaphirhynchus, m. Plate III, Fig. 2
Head strongly depressed, broad and almost elliptic, short odontodes at the rim, sides keeled, upper jaws longer than the lower ones, both with identically long, forked teeth.
The head length equals 1/3 of the body or ¼ of the total length, the breadth of the head is only ¼ of the body length, while the maximum height (down from the back head to the insertion of the pectoral fins) is only marginally larger than this breadth. The quite large eyes are four diameters away from the tip of the snout, 1 and 2/3 diameters away from the shoulder and at least three (mostly more) away from each other. The distance of the nostrils - as well as their distance from the eyes - equals to one eye diameter. All head plates are unkeeled, only the upper rim of the eyes stands out slightly and falls off at a sharp angle to the back. The large, lengthened bridging plate between the eyes and nostrils is strongly arched. The small plates at the rim of the snout overlap below and are densely covered with very short brownish odontodes. The snout is broader and more symmetrically elliptic than any other species. The not very flexible interoperculum carries a bundle of 15-18 long, thin hooks (not counting those regrowing at the rim) which are only hooked at the brownish tips at an angle of approximately 45°.
The keels along the body are of the same count and type as those of Anc. pictus; one finds 25-26 plates along the lateral line. The head channels are only discernible at the suborbital plates, which appear quite narrow due to the low lying eyes. All plates are rough, but do not carry any odontodes at their rims. The whole underside is naked down to the anal area, with the exception of the over arching rim plates of the head and the skin between the tip of the snout and the upper lip, which due to very short odontodes feels velvety to the touch. Between anal and caudal fin one finds 13 plates.
The upper lip is covered with large papillae inside, just like the middle area of the lower lip. The papillae in the corners of the mouth as well as those at the rims are very small and dense. The barbles are very short and the upper jaws are slightly longer than the lower ones. Both carry fine, slightly inwards bent teeth, just like those Hyp. barbatus. Their tips are only marginally forked and almost identical in length. Their count exceeds 30 in the upper jaws and is slightly below this number in the lower jaws. D. 1/7, A. 1/5 ... C.16
The first dorsal is longer than high, the distance from the snout equals 1/3 of the total length. The last ray, which is only ¼ shorter than the first, reaches back to the keel like supporting plate in front of the second dorsal, which only carries a short skin flap after the first, sickle shaped ray. The first ray of the pectoral fins is almost as long as the head and reaches back beyond the insertion of the ventrals. It carries numerous sabre shaped brownish odontodes which become longer toward the tip of the ray. In two specimen, they become very long, thin bristles. The first ray of the ventrals is - following the pectorals - the second strongest developed, but shorter than the following soft rays of the ventral fins. These extend back to the anal fin. The insertion of the anal fin is at the opposite side of the space between first and second dorsal and only weakly developed. The caudal fin is sloped, with the lower lobe being 1/3 longer than the upper. It is only very marginally carved in.
Coloration. Uniformly brown, even at the naked underbelly, only the inner parts of the mouth is lighter; two individuals have rather large light spots on the upper head and back; these spots are hardly discernible or completely invisible in the other specimen. All fins, especially the caudal, show traces of alternating light and dark stripes, which is, however, only visible on the rays and is mostly hardly discernible at all.
The museum owns four specimen (with two females among them) in alcohol, between 8 and 6 inches in total length, originating from Barra do Rio Negro.
There is further information on this species on the Cat-eLog page.
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