Trying to ignore work, and not ready to go home yet, I'm trolling through Galvis, G., J. I. Mojica & M. Camargo. 1997. Peces del Catatumbo. Asociación Cravo Norte, Ecopetrol, OXY & Shell, Bogotá, 118p. (available HERE if you want it)
In it I find two photos, purportedly of and . In this particular scan copy of the text, someone has hand scribbled that the two photos are reversed.
- Scan of Galvis et al. 1997 from internet, pg. 83, showing hand-written comments.
- Galvis et al. 1997. Photo labeled as C. tachiraense (possibly C. sovichthys).
- Galvis et al. 1997. Photo labeled as C. sovichthys (possibly C. tachiraense).
So how to know if the photos are swapped? I went back to Schultz' (1944) original descriptions and extracted some information.Shane wrote: 21 May 2006, 15:46The Wel Atlas ID is incorrect, but all I can do is complicate the issue more...
According to the Chaetostoma key in "Los Peces Del Rio Magdalena" (Miles, 1947) C. thomsoni can be distinguished from the other Magdalena Chaetstoma by "aletas dorsal y caudal unicolor, o con pocas bandas anchas" (dorsal and caudal fins unicolor or with a few broad bands). Further on, Miles states "cuerpo y aletas unicolores o con poca pigmentacion, 5 o 6 espinas interopercules" (body and fins unicolor or with a little pigmentation, 5 or 6 interopurculum spines).
Ok, based on this description, identify a C. thomsoni!. It is impossible and even appears that Miles is likely making reference to what are probably several distinct spp.
C. tachiraensis, on the other hand, is well defined both by Schultz (1944) and Galvis et al (Peces del Rio Catatumbo, 1997). In fact, Galvis et al even have a nice photo of C. tachiraensis. It is not the "C. cf thomsoni" common to the hobby and pictured in the Welse Atlas.
The overall body color of C. tachiraensis is similar to the common "thomsoni" of the hobby, but the caudal is deeply concave, the dorsal has "5 or 6 dark spots om membranes between dorsal rays and not on dorsal rays," and "dark pigment evident near tips of middle rays forming an obscure dark band across the rear edge of caudal, except white tips of upper and lower lobes."
The other very distinguishing feature notable in the Galvis et al photo is that C. tachiraensis has a dark rostrum (snout) with light dots and not a light-colored rostrum with dark spots like our "thomsoni." The final "smoking gun" is that "thomsoni" shipments do not come to Bogota from Tachira. In fact Tachira shipments are quite rare. "Thomsoni" show up in Villavicencio shipments. That said, I do not know if they are collected there or simply picked up somewhere between Villavicencio and Bogota from collectors in the Magdalena basin during the trip to market in Bogota.
Bottom line: 1) The Welse Atlas ID is clearly incorrect and 2) We may never know if the "thomsoni" of the hobby is really that sp or not as the available descriptions of C. thomsoni are useless as identification refs. Someone needs to go back and check Reagan's original 1904 description and see if it includes any useful identifying characteristics.
From Schultz' 1944 publication (available HERE), here is what he wrote originally to describe these two species. For (red letter emphasis added by me):
- Schultz. 1944. C. tachiraense. Few dark spots on head.
And here is what Schulz wrote for Chaetostoma sovichthys (again, red letter emphasis added by me):Schultz 1944. pp. 288-291 wrote: The body is short and its width broad as in C. anomala; the width at coracoids is equal to the distance from tip of snout to rear of supraoccipital plate and is contained 2.9 times in the standard length; a small dermal keel, a little longer than pupil, lies along middorsal line at rear tip of the supraoccipital plate; interorbital space about 1 8/10 in the snout; eye 2 1/2 in interorbital space and 4 9/10 in the snout; length of depressed anal a little longer than the width of interorbital space; plates all prickly; dorsal spine not much larger than the soft rays; pectoral spine enlarged with strong spines; soft rays of pelvics and pectorals with prickles; anterior third of snout fleshy, without plates, but with small folds; lips papillate; belly naked; a barbel at each corner of the mouth; a narrow naked area along base of dorsal, but along base of adipose the naked area is obsolete; intestines much coiled; peritoneum blackish; caudal fin deeply concave, the upper lobe equal to distance from snout to rear of supraoccipital.
Color. - Grayish brown above paler below; top of head and sides with small dark spots caudal plain grayish, as in many specimens of C. anomala anomala and C. anomala sovichthys, but the forked caudal has pale tips to the upper and lower caudal lobes; the middle rays at tips are slightly blackish, interradial membranes of caudal with black pigment; a somewhat diffuse yet distinct dark streak along midsides; traces of four dark saddles on back, one in front of dorsal, the second at front of dorsal, third at rear of dorsal, fourth through adipose base and on caudal peduncle; pectoral spines blackish above; pelvics plain like body; the conspicuous black spot between dorsal spine and first branched ray is present but smaller, then less distinct dark spots occur on the naked area of body between the bases of each soft dorsal ray, the pigment extends a trifle on the base of the interradial membranes; membranes between soft dorsal rays with five or six dark spots, the rays pale.
Remarks. - This new species may be distinguished from all other species of Chaetostoma by the small dermal fold or keel at rear tip of the supraoccipital, this keel about equal in length to diameter of pupil. Fowler (Proc. Acad. Nat. Sci. Philadelphia, vol. 91, p. 238, figs. 28, 29, 1940) describes C. furcata from Peru as having a bony protuberance at rear tip of supraoccipital, but in tachiraensis this is a dermal keel. C. furcata has I, 4 anal and I, 7 dorsal rays, while the new species has I, 5 and I, 8 rays, respectively.
The color pattern of small dark spots anteriorly on head and with the pigment spot on the interradial membranes of the dorsal instead of on the rays is characteristic of this new species. The species most closely related to tachiraensis is Fowler's C. milesi (Notulae Naturae, No. 73, p. 2, figs. 1-5, 1941) described from Honda, Colombia. This species is represented by three specimens in U.S.N.M. No. 116467, measuring 64 to 89 mm. in standard length, from the Magdalena River, Honda, Colombia. Regan's species C. thomsoni (Trans. Zool. Soc. London, vol. 17, pt. 3, p. 250, pi. 14, fig. 2, 1904), from Villeta, Colombia, is very similar to C. milesi Fowler. However, both of these species differ in color; the dorsal fin of C. tachiraensis has the color spots on the membranes of the dorsal instead of on the rays as in C. thomsoni, there is a lateral dark band on tachiraensis, but in C. milesi there are about four rows of small dark spots along the sides; all three specimens of milesi before me agree with Fowler's figures, except there are no spots on the dorsal membranes. The caudal fin is much less concave in milesi and thomsoni than in tachiraensis, it is almost forked in the latter.
- Schultz. 1944. C. sovichthys. Many small light spots on head.
From these two descriptions, I think yes, the photos in Galvis et al. 1997 are reversed. From the pictures in Galvis et al. 1997, it appears to me that C. tachiraense has a head that looks more like and the head of C sovichthys bears some mild resemblance to that of . I'm not suggesting other aspects of the species match as I've paired them here, but just the head spotting patterns are similar.Schultz 1944. pp. 292-294 wrote:Head broad, depressed, its width at base of pectoral a little greater than its length (from tip of snout to rear of supraoccipital); eyes small mostly in posterior quarter of the head; bony covering everywhere prickly; the first rays of all the fins, except anal, are enlarged and bony, with strong prickles, and those on the pectoral spine recurved spinules; the soft rays of pelvics and pectorals also with prickles; the anterior third of the snout not bony and without prickles, this fleshy area is more or less composed of very small plicate folds; both lips papillate; the small barbel at the outer corners of the lips is rather short, and is contained about 3 to 3 1/4 times in the fleshy interorbital space; two pairs of nasal openings close together near middorsal line, a little in front of the eyes, the posterior opening of each pair covered by a dermal flap; a rather wide area along base of dorsal and adipose fins naked; belly naked to anal fin; intestine elongate, much coiled.
Color. - Grayish to brownish above, paler below, the blackish peritoneum conspicuous through the skin; five pale areas dorsally separated by dark saddles, the first at front of dorsal, second at rear base of dorsal, third in front of adipose fin, last behind that fin; these dark-colored saddles join along midsides to form a more or less obvious wide lateral band. Top of head finely mottled or speckled with pale; dorsal fin barred, the black and pale areas on the rays, the membranes pale or plain grayish; caudal fin with three distinct bars on upper and middle rays with an additional bar on the lower lobe near the ends of the rays, seldom are there two or four bars on the upper lobe of the caudal fin; pelvics sometimes with two dark bars and pectorals plain or with about three or four bars; anal with its base usually blackish; dorsal fin with a conspicuous black spot on the membrane between the bases of the spine and first soft ray; belly yellowish when alive and also the tip of the upper lobe of caudal fin yellowish.
Remarks. - This new subspecies differs from anomala Regan of the Rio Chama system, Maracaibo Basin, in having a larger eye, in reference to width of interorbital space, and in color. The eye is contained 2.3 to 3.0 (average about 2.7) in the interorbital space in sovichthys of the Rio Motatan system, and in anomala 2.7 to 3.3 (average about 3.0) on specimens of comparable sizes, 25 to 75 mm. in standard length. The dark bars on the upper lobe and middle rays of the caudal fin in sovichthys are wider and number three, only occasionally two or four, while in C. a. anomala they are narrower and almost always number four, only rarely three or five; thus the caudal fin of the Rio Chama form is barred the same as the dorsal, while sovichthys of the Motatan system has more distinct but fewer dark bars across its caudal. There are in addition some statistical differences in bodily proportions when the same sizes of specimens are compared.
I hope this is helpful, and if it's incorrect, please tell me.
Cheers, Eric
