S. leucosticta is frequently available in the ornamental trade and farmed for the purpose in several countries. It is often confused with its congener S. jurupari in aquarium literature and on websites, but is easily recognised by presence (vs. absence) of prominent white spots or vermiform markings on the sides of the head.
Although the presence of white spots on the head does not distinguish it from all known Satanoperca populations (see below), it can at least be separated from all nominal congeners by the following combination of characters: presence of a relatively small dark ocellus on the upper caudal-fin base; absence of well-defined dark blotches on the sides of the body (although some forms do display dark markings on the body when stressed or sleeping); presence of small or large white spots on the sides of the head; absence of black spots at the base of the dorsal-fin; absence of a dark lateral stripe on the body.
The precise identity of S. leucosticta is a confusing issue, however, with differences in colour pattern (presence or absence of a reddish stripe in the dorsal portion of the body, variable fin colouration, extent of pale or iridescent markings on the head, body and fins, etc.) and morphological characters observed across its range, and possible conspecific forms with similar white spots and vermiculations on the head inhabiting the Branco, Negro, and upper Orinoco river basins.
Among these, the congener S. mapiritensis (Fernández-Yépez 1950) from the middle and lower Orinoco grouped most closely with S. jurupari and was clearly distinct from S. leucosticta in recent genetic analyses. A form with white spots on the head (but crucially, not the gill covers) from the upper Negro, Casiquiare, and upper Orinoco basins in Brazil, Colombia, and Venezuela was not included, however, nor was a Brazilian population purportedly from the rio Branco and lower rio Negro. The latter is known as S. sp. 'Amazonas red' in the aquarium hobby, and exhibits an ovophilous, rather than larvophilous, reproductive strategy. Here on SF such unidentified forms will be included in this profile as S. cf. leucosticta until their identities can be established, since the possibility that they form a single meta-population with S. leucosticta in the Orinoco-Casiquiare-Negro system (as may be the case for a group comprising S. jurupari, S. mapiritensis and a form known to aquarists as S. sp. 'alto-negro') cannot currently be ruled out.
Satanoperca was considered a synonym of Geophagus for a number of decades before being revalidated by Kullander (1986). It is separated from all other members of the putative cichlid subfamily Geophaginae by presence of a small ocellated spot at the upper caudal-fin base, and from Geophagus by a number of morphological characters as follows: equal numbers of abdominal and caudal vertebrae or one more abdominal vertebra (vs. more caudal than abdominal vertebrae in Geophagus); no ribs on caudal vertebrae and no postabdominal swimbladder extensions (vs. presence of both in Geophagus; cheek scaled rostrally to centre (vs. naked on anterior half; dorsal and anal fins naked (vs. scaled); external gill rakers on lower limb of first gill arch attached to the skin covering the gill filaments (vs. attached to ceratobranchial skin); jaw dentition reduced to one or two short series in each jaw (vs. pluriseriate with wide band of inner teeth); absence (vs. presence) of tooth plates on 4th ceratobranchial; presence (vs. absence) of an ocellus on caudal-fin base; both or only upper lip fold continuous (vs. both interrupted anteriorly); preoperculum and supracleithrum frequently serrated (vs. entire); absence (vs. presence) of median hypural cartilage; 3 (vs. 4) infraorbitals.
The genus is likely to contain additional species, and has been separated into three groups with distinctive morphology, namely the S. jurupari group, the S. daemon group, and the monotypic S. acuticeps group.
Among these, members of the S. jurupari group are characterised by a colour pattern comprising a dark lateral stripe or row of blotches along the side of the body, normally XV.10 (XIV-XVII.8-11) dorsal-fin rays, normally 27 (26-28) E1 scales (the longitudinal row immediately above the lower lateral line, excluding the pectoral girdle), and 12-18 rakers on the first gill arch.
S. daemon group members grow larger than other congeners, possess one or two large dark blotches on the side of the body and a prominent ocellus at the upper caudal-fin base, usually XIX.13 (XII-XIV.12-14) dorsal-fin rays, 29-31 E1 scales, and 18-22 gill rakers. S. acuticeps is unique in that it has a relatively more terminal mouth than all other genus members, normally XIII.12 (XIII.11-12) dorsal-fin rays, 27-28 E1 scales, and 17-20 gill rakers.
The groups also differ in reproductive strategy, with the S. daemon and S. acuticeps assemblages being substrate spawners, and the S. jurupari group mouthbrooders.
Satanoperca and a number of related genera are often included in the putative subfamily Geophaginae, and Kullander (1998) conducted a morphology-based phylogenetic study in which the neotropical Cichlidae was divided into six subfamilies of which the Geophaginae contained 16 genera divided among three 'tribes':
Acarichthyini - Acarichthys and Guianacara.
Crenicaratini - Biotoecus, Crenicara, Dicrossus and Mazarunia.
Geophagini - Geophagus, Mikrogeophagus, 'Geophagus' brasiliensis group, 'Geophagus' steindachneri group, Gymnogeophagus, Satanoperca, Biotodoma, Apistogramma, Apistogrammoides and Taeniacara.
Later molecular studies by Farias et al. (1999, 2000, 2001) resulted in the additions of Crenicichla and Teleocichla to the Geophaginae, a result supported by López-Fernández et al. (2005) who conducted the most detailed molecular analysis of the grouping to date including 16 of the 18 genera and 30 species.
However their conclusions regarding interrelationships between genera did vary somewhat from previous hypotheses and can be summarised by the following loosely-defined groups:
- a weakly-supported sister group relationship between Acarichthys and Guianacara.
- a well-supported 'Satanoperca clade' comprising Satanoperca, Apistogramma, Apistogrammoides and Taeniacara.
- a 'big clade' with Geophagus, Mikrogeophagus, 'Geophagus' brasiliensis group, 'Geophagus' steindachneri group, Gymnogeophagus, Biotodoma, Crenicara and Dicrossus.
- a 'crenicarine clade' with Biotoecus and Crenicichla.
No representatives of Teleocichla or Mazarunia were included in the study but the former is well-established as sister to Crenicichla while the latter has grouped closely with Dicrossus and Crenicara in earlier works.
The other main conclusions of the paper are confirmation that Geophaginae is a monophyletic group exhibiting strong signs of having undergone rapid adaptive radiation.
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