Chortiheros wesseli (Miller, 1996)

Etimologia: Dedicated to the amateur naturalist devoted to gathering information on the ecology, behavior, and identification of Middle American cichlids. Richard (Rusty) Wessel, who is among the many enthusiastic cichlidophiles who are obtaining information of great value to professional ichthyologists (Miller, 1996:180).

Nomi comuni: Honduras Mojarra.

Tipi: holotype: UMMZ 231103 (1), paratypes (8): UMMZ 223306 (8).

Holotype: An adult male 110 mm SL (standard length) stored in the University of Michigan Museum of Zoology with registration UMMZ 231103.

Paratypes: 8 juvenile to adult specimens 36-112 mm SL. Stored with registration UMMZ 223306.

All nine specimens are from the Rio Belleaire at CA 13 bridge (near Entelina), 8 km south of the Rio Jutiapa crossing, in the Rio Papaloteca drainage, Departmento de Atlantida; 15° 41' 30" W. Lat., 86° 30' N. Long., 02 June 1993, collected by Rusty Wessel and party.

Diagnosi: Chortiheros wesseli differs from other species in Theraps (as a group sensu to Regan, 1905) by the following combination of traits: (1) a very slender body, (2) a lateral stripe from the upper end of the opercle, below the upper lateral line, rising to the level of the lower lateral line and extending from snout to base of caudal fin, (3) no vertical bars on sides, (4) a round or squarish black spot at base of caudal fin, (5) a pointed snout positioned high on the head, (6) an oblique mouth, and (7) with nuptial colors that are jet black on the venter in both sexes (From Miller, 1996:180).

Dimensione: The largest specimen in the type series is 112 mm SL. which accounts for approximately 14 cm in total length. The largest male I have seen in captivity is about 15 cm in total length, while the largest female about 10 cm.

Dimorfismo sessuale: Males are larger, less colorful than females and have a longer snout.

Località tipo: Río Belleaire at CA13 bridge, 8 km south of the R. Jutiapa crossing, Atlantida, 15°41'30.

Distribuzione: Chortiheros wesseli in at least three streams in Northern Honduras, the Rio Jutiapa, Rio Belleaire and the Rio Hauron. All three sites are within the Rio Papaloteca basin in the eastern part of the Departmento de Atlantida [Honduras] between the coastal city of La Ceiba and Sava (Saba on some maps). All three streams originate in the cloud forests of the coastal Cordillera Mountain range and flow into the Caribbean Sea (Wessel, 1998).

Habitat: Chortiheros wesseli was initially captured at the Belleaire River crossing opposite Entelina at the second bridge overpass east of Jutiapa. This river, a tributary to the Rio Jutiapa, had a maximum width of 20 m and was flowing at 1 m/sec over a bottom of boulders (45%), rocky rubble (25%), riffle and sand (25%), and silt (5%). The water clarity during the dry season (January to June) is referred to as spectacular. River depth was about 2.4-3.0 m and there was little marginal vegetation, with some algae on the rocks. Water pH is around 7.8, soft and with a temperature was 24.5-25 °C. No trees grew along the banks where the fish were collected, although they are lined with lush green vegetation. The new species prefers areas with boulders, rocks and the fastest flow. Even in natural habitat this fish is rare, Rusty Wessel gave a rough estimate of one C. wesseli per one thousand other fish (Compiled from Miller, 1996:183; Wessel, 1998).

Località:

Jutiapa

Rio Jutiapa

Conservazione: Chortiheros wesseli non inserita dalle organizzazioni internazionali di salvaguardia delle specie a rischio nella lista rossa.

Alimentazione: There are not feeding records for C. wesseli, but the shape and position of the mouth indicates it does not feed on aufwuchs, but more likely it is an insectivorous or crustacean eaters.

Riproduzione: Both males and females of Chortiheros wesseli develop a breeding dress characterized by the lower half of their bodies turning velvety black, while the upper parts remain very clear, with the females having more extended and deeper black coloration. This situation is understandable as females, being smaller and in closer contact with the fry, require a stronger signaling of their aggressive disposition to potential threats while breeding. Males on the other side, being larger and less committed, do not regularly employ as much energy in their dress, avoiding with this the additional unwanted predator attention that a striking breeding color brings, small males may color as strikingly as females though. This color remains for the whole breeding phase, and begins a week or so before breeding commences and lasts until the fry are about 25 mm long.

C. wesseli is a bi-parental substrate brooder, eggs are placed in cracks between the rocks number in the few hundreds. Pairs guard for eggs, wrigglers and fry in the strong current of the river among the boulders, with the female guarding the immediate position of the eggs and fry while the male guards the surroundings. Males have a lower compromise than females in the defense of the fry and will flee away when threats approach Miller, 1996:182).

Aquariofilia: Chortiheros wesseli was first introduced to the aquarium hobby by Rusty Wessel following its capture in 1991. It was then bred and distributed in the United States. Stock from Rusty Wessel was sent to Europe at the beginning of the 2000’s. I am just aware of an aquarium keeping report by Stawikowski & Werner (1998:417) where a picture of a male and female (obtained from Rusty) are shown in aquarium.

C. wesseli may be quite aggressive in captivity and hence a large aquarium of over 150 cm with items that break off the line of sight are necessary for its successful keeping, as otherwise they can bite off their tails. Sand and rocks are ideal decorations, matching natural habitat. Hiding places should be provided and are readily used by this otherwise very shy fish. Dither fish and other equally or less aggressive companions are very useful to make the fish feel comfortable, and partially overcome its shyness. C. wesseli in aquarium never rise above the rock level, always staying as low as possible. Food is not a problem, regular aquarium foods are accepted without problem; cichlid sticks and frozen foods, like mysis and brine shrimp.

Water quality is of high importance, high oxygenation and frequent water changes are necessary for the well-being of this species. Water current in the tank is highly appreciate it by the fish. The temperature and water chemistry are best to be provided in accordance to natural parameters (pH 7.8, rather soft water and °C.), although there are no records I am aware of this species being kept under different conditions.

This species has been successfully bred in aquarium in several occasions and they have proven to be good parents. They spawn in cracks among the rocks (not in caves) and are reported to produced 300-500 eggs depending on the size of the female (Woodland, 2011:115). Fry are guarded closely by the female and can immediately be fed baby and de-capsulated brine shrimp and latter moved to flake food. The fry grow fast and may reach 2.5 cm in just over six weeks, after which slow rate decreases. (I thank Dan Woodland for his detailed keeping account).

Commenti: When Robert Miller described Chortiheros wesseli (as Theraps wesseli) he expressed the lack of limits for the genus Theraps and suggested a temporary placement of his species in this genus (Miller, 1996:179). He saw Chuco microphthalmus (p. 183) (for him in Theraps) as the sister species of C. wesseli, but at the same time recognized the lack of similitude of these two species with Theraps irregularis, the type species of the genus.

Both Concheiro Pérez et al (2007) and Oldřich Říčan et al (2008:952) showed that both T. irregularis (type species of Theraps) and C. wesseli are only very distantly related, and in fact belong to two different lineages; C. wesseli to the lineage of amphilophines (with Isthmoheros and Hypsophrys) instead of the herichthyines, where Theraps is nested. The use of new generation ddDNA comparison by Říčan et al ([ref1=7292]:21) resolved the philogenetic position of C. wesseli as a long separated sister species of Petenia splendida. Given their different combination of cranial (generalized versus highly specialized in Petenia) and post-cranial (elongated versus generalized in Petenia) morphology the new monotypic genus Chortiheros was erected for C. wesseli. The diagnosis was based on morphological traits related to the elongated shape of the body, the sexually quiescent melanin color pattern and the unique (for Amphilophines) breeding color pattern, more reminiscent of Herichthys than of any other amphilophine. Chortiheros wesseli is the best adapted rheophilic amphilophine and not closely related to the other rheophilic amphilophine genera (e.g. Talamancaheros, Neetroplus) and occupies a distant allopatric and limited distribution ([ref2=7292]:26).

It turns out as amazing that this fish had not been discovered before Rusty Wessel did in 1991. In 1969 and 1970, Michael Martin (1972) spent a total of seven months covering all the major drainages in Honduras. This resulted in the preservation of about 26,500 specimens from 182 localities. In addition, he examined approximately 6,600 specimens of Honduran fishes preserved in several museums, and C. wesseli was not part of such results (Compiled from Miller, 1996:179).

My good friend and for many years travel companion Rusty Wessel, who discovered this fish, likes to tell the history of how difficult this fish was to collect. Being Rusty an extraordinaire collector (the best I know) I can appreciate the meaning of his words. The fish is not only rare but goes into the cracks of the rocks as soon as it perceives some danger. Rusty would go in the night to try to collect some specimens while they slept, to be used by Dr. Miller in the species description. He managed to collect some fish but they were still too few. In an illuminated idea, he visited the bar at the closest town and asked for fishermen to collect the fish for him, for a nominal fee each. Next day visit produced five specimens, it was good but yet not enough. He paid as promised and so the following day to his surprise over a hundred fish were presented to him!.