Apistogramma sp. "Diamond-band", aggressive male with typical lateral band.
(All photos, unless noted otherwise: Uwe Römer)

The Habitat

In August 2014 MEJIA found A. sp. "Rautenband / Diamond-band" ³ Endnote 3 ³ We will use the English name Diamond-band for the species from here on in this manuscript translation regardless of the fact that the original name coined was and is A. sp. "Rautenband". in a stream south of Mitú that flows into the Río Vaupés. In 1992 Uwe WERNER (Ense-Bremen, Germany) had caught A. sp. "Mitu" in the Río Cuduyari, a left-hand tributary to the Río Vaupés north of Mitú. Since the fish caught by MEJIA looked quite similar to A. sp. "Mitu" and were caught not far from the latter´s collecting site, it was initially believed that it could in fact represent this species.

Habitat of Apistogramma sp. "Diamond-band", a typical blackwater stream.
(Photo: Daniel Mejia)

However, as we will explain in the following, in our opinion it is a clearly distinguishable and separate species. The habitat of A. sp. "Diamond-band" is a blackwater stream with quite strong current in some areas. However, A. sp. "Diamond-band" were exclusively found in zones with calm and shallow water where thick layers of leaf litter and aquatic plants provided good hiding places. In these areas the animals were always to be found in small groups. Another Apistogramma species also been found in this stream is A. cf. personata (RÖMER et al., 2017). However, these not only lingered in shallow water zones, but also in deeper water areas. They could also be found in the surrounding streams and ponds, whereas A. sp. "Diamond-band" were not found there. Unfortunately, the water parameters in the stream inhabited by A. sp. "Diamond-band" were not measured, but most of the surrounding waters had a pH value of 5 or lower, very low electrical conductivity, and temperatures of 23°C in the early morning and up to 28°C later in the day (MEJIA, pers. comm. to FH).
In addition to the two Apistogramma species, numerous species of other genera were caught. In the shallow water areas inhabited by A. sp. "Diamond-band", besides Nannostomus marginatus EIGENMANN, 1909, species of the genera Rivulus POEY, 1858, Copella MYERS, 1956, Melanocharacidium BUCKUP, 1993 and Hoplias GILL, 1903 as well as a species of knife fish and fresh water shrimp of the genus Macrobranchium BATE, 1868 were caught. In the deeper areas, among others, Parotocinclus cf. eppleyi SCHAFER & PROVENZANO, 1993, Cichla BLOCH & SCHNEIDER, 1801, and Crenicichla HECKEL, 1840 as well as large predatory tetras were collected.

Apistogramma sp."Diamond-band", male with far protruding mouth.
  

Apistogramma sp. "Diamond-band", adolescent aggressive female in lateral threat. However, because of the shape of the dorsal fin, it could also be a not yet fully developed male.

A comparison of this information with the habitat data recorded by UR in February 1994 (i.e. during the low water period) seems interesting. The two collecting sites, located about 30 km apart from one another, in the Igarape Irá, a right-hand tributary (which was about 50 meters wide in the investigated area) of the Rio Uaupés, represented blackwater habitats with very different structures (field numbers F6- and F7-B-1994-R). The following parameters were determined on site around 10:00 (am) (F6) and at about 15:30 (03:30 pm) local time (F7): Temperature 26.5/27 °C, electronically measured pH of 4.3/5.3. The site F6-B-1994-R was a shallow sandbank densely covered with an undetermined grassy plant. Besides eight with a total length (TL) of about 2 cm approximately half grown specimens of A. sp. "Diamond-band", numerous adult A. elizabethae KULLANDER, 1980, a few half grown A. cf. personata, young Crenicichla sp., and masses of juveniles of Laetacara fulvipinnis SCHINDLER & STAECK, 2007 could be detected (RÖMER, 1998).

Apistogramma sp. "Diamond-band", aggressive female in lateral threat.

Apistogramma sp. "Diamond-band", neutrally mooded dominant female.

Apistogramma sp. "Diamond-band", neutrally mooded male outside the brooding phase with distinct vertical bars and typical shape of the lateral band.

Apistogramma sp. "Diamond-band", aggressive male before attacking another male.

At site F7-B-1994-R, a shore area of the Igarapé Irá covered with a thick layer of leaves at its confluence with one of its small tributaries, besides few adult A. elizabethae, A. meinkeni KULLANDER, 1980, small indeterminable Crenicichla , Geophagus HECKEL, 1840, Satanoperca GÜNTHER, 1862, and Heros HECKEL, 1840, three juvenile specimens of the "Diamond-band"-Apistogramma were caught.

All in all, the data collected so far suggest that the dwarf cichlids introduced here are a quite widespread species in the drainage of the Río Vaupes / Rio Uaupés, but with only relatively low abundance. This assumption is also supported by recent commercial imports due to Aquarium Glaser (Rodgau) in the years 2015 and 2016. In the shipments of A. cf. personata imported from Colombia some A. sp. "Diamond-band" were mixed in, but also in only very small numbers.

Maintenance and Breeding

A. sp. "Diamond-band" is an extremely aggressive species, a striking parallel to A. cf. personata distributed in the same river system (RÖMER et al., 2017). For the sustainable maintenance of a pair, a tank with a base of at least 80 x 35cm or larger should be chosen, which offers sufficient hiding and withdrawing possibilities. A very harmonious pair though may be kept in a smaller tank, strongly structured by roots, plants, leaves and caves. However, in this case an alternative tank should always be available to be able to separate the fish if necessary. The common accommodation with larger Apistogramma species having similar demands on the water chemistry (e.g. adult "Breitbinden/Broad-banded"-Apistogramma) may also be helpful in curbing the high intraspecific aggression.

Apistogramma sp. "Diamond-band", dominant female shortly after spawning. Only the lower half of the body is intensely yellow, while the upper half is still greyish-beige.

Apistogramma sp. "Diamond-band", female in a quarrel over a breeding cave.

As with all Apistogramma species, very fine, rounded sand is recommendable as substrate, since their natural way of food intake consists mainly of picking up sand with their mouths, sifting out the food, swallowing it, and expelling the sand through the gills again. An important side effect of this type of food intake is the cleaning of mouth and gills, which is very important for the long-term health of all Apistogramma. Since A. sp. "Diamond-band" is a black water species, the water

Apistogramma sp. "Diamond-band", female in the brood cave about 24 hours after spawning.

should be very soft and acidic (electric conductivity less than 100uS/cm, pH value 4.5-5.5) and enriched with humic substances, e.g. by peat filtering or the addition of almond leaves or – more cost-efficient – beech leaves. Even if excellent living conditions are offered to the fish, breeding may still be difficult. Ernst van GENNE (pers. comm. to FH), for example, reported that out of more than a dozen clutches only once fry developed to the free-swimming stage. And none out of eleven clutches produced by UR’s fish hatched. Spawning is preceded by an intense courting ritual, which may last for several hours, in some cases even up to two days. With wide spread fins the male fast approaches the female ready to spawn, presenting a greenish- or bluish-sooty blotch on its flank below the lateral band. They regularly show a similar pattern too during aggressive conflicts to opponents of their own, sometimes to those of other species. The significant difference marking courtship behavior consists in the fact that the male approaches the female in this situation not in horizontal, but in slightly diagonally tilted backwards body position. In doing so, it at first place presents its unprotected throat region to the female. Apparently this behavior suppresses the otherwise observable escape reaction of females when being approached by males in aggressive mood. While heavily courting, consisting of lateral head-jerking, lateral presentation of the fully spread fins, and "Leitschwimmen"⁴,  Endnote 4⁴ The German language term “Leitschwimmen” describes an in many cases strongly ritualized behavior in which one of the mating partners (like it is the case in the European Three Spined Stickleback Gesterosteus acculeatus L.) demonstratively swimms in front of the partner and tries to lead him to the nest, cave, or whatever will be the later on spawning site. the male accompanies the female ready to spawn to the spawning site. The spawning mood of the female becomes visible over several days by increasing corpulence. However, the actual spawning mood is manifested only few hours before spawning by the clear protrusion of the genital papilla. Spawning takes place in typical Apistogramma manner, preferably in caves or other hiding places. The female often secures the entrance of the cave by piles of sand against potential intruders and vigorously defends the area around the cave.

Apistogramma sp. "Diamond-band", aggressive dominant female shortly after spawning.

Apistogramma sp. "Diamond-band", female in slightly aggressive brood care coloration. The lateral band is dissolved into a signified pattern of spots.

The male of the facultative polygamous species takes over defending the whole territory, in which individual territories of several females may be located. Particularly if using a smaller tank, special attention has to be paid after spawning, in order to prevent aggression between the partners to prevail and to be able to evacuate the male to another tank in time if necessary.

Apistogramma sp. "Diamond-band", female guarding some days old fry.
(Photo: Frank Hättich)

At a water temperature of 26°C the larvae hatch after about three days. Before the free-swimming of the fry, approximately seven days later, larvae are sometimes moved to one or even successively several other caves or hides – a behavior also known from the females of many other Apistogramma species (comp. RÖMER, 1998, 2006). After free-swimming the male may also be involved in leading the fry. Cautiously fed freshly hatched Artemia nauplii twice a day and doing water changes of 60 % once a week, the fry grows up fast. After six weeks at the latest, they have reached a degree of independence that makes the presence of their parents superfluous. They can now easily be transferred to another tank for further rearing. After only about three months the juveniles develop the pronounced intraspecific aggression already known from the parents. That’s why grow-out tanks should also be well structured with a lot of hiding places. Well-watered perforated bricks, in which´s numerous caves the young fish can stay protected without taking notice of each other, have proven to be particularly suitable for this purpose in aquaria of UR. Such bricks are not particularly decorative, but the frequency and intensity of intraspecific aggression of the "Diamond-band"-Apistogramma significantly decreases compared to tanks merely structured by means of plants or deadwood.

Phenotypic Features

A. sp. "Diamond-band" has a slightly elongated, moderately high-backed body shape and with 6 to 7 cm total length (TL) in males and about 4 cm TL in females does not become particularly large. Large males can appear robust, but they do not become as brawny as e. g. A. macmasteri KULLANDER, 1979. The base colour of the body can range from a very light, sometimes almost white, to a honey-colored beige tone. In addition to shiny bluish-turquoise stripes, males can also show extensive red spots or wormline markings on the entire lower half of the head. Less often and less pronounced this may also be the case in females. In some males, a few red points, spots, or scale edges are also visible on the upper abdomen. A preorbital stripe is shown sometimes, whereas a supraorbital stripe is visible only very rarely, and if so, only very vaguely. The suborbital stripe begins at the eye at about the width of the pupil, becomes distinctly narrower towards the posterior lower edge of the gill cover and often ends tapering there. Sometimes a stripe appears between the eyes, carrying a spot in the middle, as it is often found in similar shape in species related to A. macmasteri and A. alacrina, but also in other species-groups. As in most species showing such markings, the shape of this spot is highly variable.

Apistogramma sp. "Diamond-band", adult dominant male in neutral mood. (Photo: Frank Hättich)

Apistogramma sp. "Diamond-band", dominant male chewing detritus.

The dorsal fin of males is deeply serrated with membranes slightly or up to about 30% longer than the spines, especially in the anterior part (half) of the fin. In females, the distal edges of these membranes are truncated, but may also be slightly pointed in the frontal part of the dorsal fin by way of exception. The two anterior membranes are usually blackish in both sexes. In males, the mostly iridescent greenish-turquoise dorsal fin carries a seam at its upper edge, that – depending on mood – may be transparent, sooty or sometimes red. The edges of soft parts of dorsal and anal fin of males are pointed, sometimes slightly elongated, and show a pattern of whitish or hyaline-bluish stripes or spots at their bases. In females these soft parts are usually rounded and, mostly, only that of the anal fin shows a few light spots. The anal fin can be bluish in both sexes.

Apistogramma sp. "Diamond-band", suppressed female with typical pattern.

Apistogramma sp. "Diamond-band", subdominant female before an attack by a male. Typical pattern with vertical bars, dark scale edges, lateral band dissolved into spots and large caudal spot.

The transparent, in some cases also slightly milky-cloudy caudal fin is rounded in males and females. In males, it may show an irregular pattern of pale, whitish-bluish (hyaline) points in its distal part exceptionally. The ventral fins in females and often also in males show a black seam at their frontal edge and, even in large specimens, are not elongated.

In adult individuals, pronounced vertical bars are rarely seen. However, distinct dorsal spots are present, often merging to a dorsal band that may be extended forward to the level above the pupil. The lateral band, usually continuous in adult individuals, adjoins the postorbital stripe without interception. It increases in width from about 1 scale height in the first third of the body reaching its maximum width of 1 1/2 to almost 2 scale heights and remains constant in width up to the area of the seventh vertical bar. Here, especially at its lower edge, usually further dark scale edges are added, which widen it once again up to 3 1/2 scale height.

Apistogramma sp. "Diamond-band", subdominant female after a lost fight with a dominant female. Typical "dirty" pattern with pronounced vertical bars and lateral band dissolved into spots.

However, the start of this widening is quite variable and may already start in the position of the sixth, sometimes even the fifth vertical bar. In adults, the lateral band usually consists of an anterior zigzag-shaped part that towards the caudalmost part changes into lined up, laterally rounded diamonds, sometimes also laterally compressed hexagons, with light colored centers, just as often seen in the lateral band of species of A.-macmasteri-relatives. Due to the dark scale edges, added in the area of the posterior vertical bars (thereby widening the lateral band) usually further complete diamonds or hexagons are formed there (which prompted us to choose the common name). In this way a pattern of often six, sometimes up to eight and in exceptional cases even ten diamonds/hexagons may occur in this area. For simplification, we will only use the term diamonds in the following, even if in some cases genuine hexagons are formed. The lateral band of A. sp. "Diamond-band" may show a more or less pronounced zigzag- or diamond-shaped portion, but depending on mood, can also completely turn into one or the other of the two forms. Sometimes additional dark pigmentation is present in and around the area of the lateral band at the position of the seventh vertical bar. If the resulting blotch is particularly intensive, this may induce the impression of a "second caudal spot". Especially in juveniles, this dark blotch in the seventh vertical bar is often visible. Mostly in juvenile individuals, the lateral band sometimes dissolves into blurred, vertically extended blotches at the intersections with the vertical bars. The lateral band is followed by a clearly separated, variably shaped caudal spot. In adults its shape is usually vertically extended oval, more rarely vertically extended rectangular with rounded edges.

Rarely two or three rows of abdominal dashes or, instead, – exceptionally – abdominal stripes are visible, starting behind the pectoral fin and become blurred or disappear completely in the caudal half of the body. A pectoral spot at the upper edge of the pectoral fin base is apparent in both sexes. Female A. sp."Diamond-band" usually, but latest after reaching sexual maturity, show a short black mid-ventral stripe in front of the anal opening. In males a mid-ventral stripe is visible too sometimes, but most distinctly in aggressive mood. It may extend from the anal fin base close to the ventral fin base. Likewise, in this mood a sooty blotch appears on their belly below the lateral band, occasionally overlaid by a greenish or bluish metallic sheen, comparably known most prominently from some species related to the A-macmasteri and its closer congeners (see e. g. BOHNET et al., 2005; GLASER & GLASER, 1996; RÖMER, 1998, 2006; STAECK & LINKE, 2006).

As usual for Apistogramma species, body and fins of brooding A. sp. "Diamond-band" females turn into yellow color, which, however, is often less intense, especially in the upper half of the body compared to many other species. During brood care, females usually show a dorsal band and a mainly continuous and mostly zigzag-shaped lateral band.

Considerations on the Systematic Position

The following remarks about the systematic position of A. sp. "Diamond-band" within the genus Apistogramma, are based on the classification of the genus into lineages, species-groups and -complexes as proposed by Mike WISE (2011a)⁵.  Endnote 5 ⁵ The systematics of the genus Apistogramma currently has to be considered provisional at best. Purely for practical reasons, we have therefore agreed that alternative (including our own) ideas on the systematics are not taken into account in our considerations here, especially as results of genetic studies currently in progress or print (with in part clearly differing systematic statements) cannot be taken into account here for reasons of publishing laws. Due to the absence of a lateral spot as well as (in normal coloration) pronounced vertical bars, body shape, and shape of lateral band, only the allocation to the A.-macmasteri- or A.-alacrina-group seem to be in line for A. sp. "Diamond-band". Both groups belong to the A.-regani- lineage, which encompasses almost half of all known species and forms of the genus.

Apistogramma sp. "Diamond-band", female. Some dominant females can show red spots on the gill covers.

Concerning to its body shape, A. sp. "Diamond-band" could be positioned within both, the A.-macmasteri- as well as the A.-alacrina-group. In both cases they represent one of the smaller and less brawny species. Their strongly serrated dorsal fin, which is slightly extended in the anterior part, fits the A.-macmasteri-group, but not the A.-alacrina-group, in which all known species have low and truncated dorsal fins. In addition, at least in its anterior part, the faint band is missing, which in species of the A.- alacrina-group often delimits the seam of the basal parts of the dorsal fin.

The sooty blotch on the belly, shown by the males during aggression or display, also is not known from species of the A.-alacrina-group, but visible in many species of the A.-macmasteri-group. However, it does not seem to be strictly limited to species of this group, since similar belly-blotches have been observed in A. megaptera, A. cf. personata, A. sp. "D10", A. sp. "D50", and a form related to A. agassizii (see HÄTTICH & KIPPER, 2017; RÖMER, 2018.).

The lateral band, depending on mood more or less zigzag- or diamond-shaped, reminds of species of both systematical groups. If containing a diamond-shaped part, it is more similar to the species of the A.-macmasteri-group, since the species of the A.-alacrina-group usually show a completely zigzag or zipper-like lateral band (in the latter, two parallel rows of vertical dashes are arranged offset to one another horizontally). But A. sp. "Diamond-band" often also shows a zigzag-shaped lateral band. In contrast to it, the caudalmost part of the lateral band in species of the A.-macmasteri-group usually becomes considerably narrower. It especially does not show widenings in its part from the fifth to seventh vertical bar due to additional scale edges or any pattern of diamonds produced by these. Just like in A. sp. "Diamond-band", the lateral band of species within the A.-alacrina-group after reaching the widest point often retains its width, and – only rarely – is even widened by additional scale edges at its caudal end.

Apistogramma sp. "Mitu", female in beginning territorial coloration. (Photo: Uwe Werner)

Apistogramma sp. "Mitu", adult male. The pattern of diamonds at the end of the lateral band can be clearly seen (see also Römer, 1998, p. 863). (Photo: Uwe Werner)

This can be observed regularly and distinctly most notably in one species of the A.-alacrina-group, namely in A. sp. "Mitu". At the caudal end of its zigzag-shaped lateral band, even a distinct pattern of diamonds is created occasionally, similar to what is observable in "Diamond-band"-Apistogramma. Nevertheless, adult specimens of both species are clearly distinguishable from each other by a number of other characteristics. A. sp. "Diamond-band" for example is usually less elongate and more high-bodied compared to the very slender A. sp. "Mitu". Furthermore, the dorsal fin of A. sp. "Mitu" is low and truncated, carrying a faint band like often seen in species of the A.-alacrina-group, delimiting the seam of the dorsal fin downwards, which is missing in – at least in the anterior part of – the significantly higher and strongly serrated dorsal fin of adult A. sp. "Diamond-band". The caudal spot of A. sp. "Mitu" is round to horizontal-oval, in some cases also square with rounded corners, whereas that of A. sp. "Diamond-band" is vertically-oval, in rare cases also vertically-rectangular with rounded corners. We therefore have no reasonable doubts that these are representing two separate species.

Apistogramma sp. "Diamond-band", female in aggressive brood care coloration. Upper half of the body more greyish-beige instead of intense yellow. (Photo: Bruno Magis)

Apistogramma sp. "Diamond-band", dominant female with more orange colored brood care color shortly after spawning.
    

Nevertheless, A. sp. "Mitu" may appear very similar to slender, younger "Diamond-band"-Apistogramma, which have not yet clearly developed the serrated dorsal fin. Besides the proximity of their collecting sites, this was probably one of the reasons for the initial identification of A. sp. "Diamond-band" as A. sp. "Mitu". However, it should be noted, that the lateral band of A. sp. "Diamond-band" in its zigzag-like expression indicates a closer relation to A. sp. "Mitu", and thus to the A.-alacrina-group. But apart from characteristics indicating an affiliation of the "Diamond-band"-Apistogramma to the A.-macmasteri- or A.-alacrina-group, their non extended ventral fins and brooding-coloration of females are features which in this form do not occur in either of the two groups.

Apistogramma sp. "Diamond-band", female threatens the courtshiping male at the cave entrance. (Photo: Frank Hättich)

Apistogramma sp. "Diamond-band", courting male with typical belly-blotch in front of the female (in the background).

At first glance, the collecting site in a tributary of the Río Vaupés seems to indicate that it may belong to the A.-alacrina-group. With A. sp. "Mitu", a member of this species-group occurs in the immediate vicinity of A. sp. "Diamond-band", whereas so far no species of the A.-macmasteri-group has been found in the Río Vaupés system. However, some species or forms belonging to the A.-macmasteri-group have recently been discovered in the Río Guaviare. Among these A. sp. "Pacman" (also known as A. sp. "D12"), a species from the immediate vicinity of the city San Jose del Guaviare, only a bit south of which the headwaters of the Río Vaupés begin to expand (MEJIA, pers. comm. to FH). Therefore it seems conceivable that ancestors of these species from the Río Guaviare may have reached the headwaters of the Río Vaupés system, and from there have spread out further within this river system. In the course of evolutionary adaptation processes, A. sp. "Diamond-band" may have emerged from one of them. Following another hypothesis of WISE (2011b), A. sp. "Mitu" may also have been emerged in similar way from one of the species of the A.-alacrina-group, spreading from its region of origin, the area of today's upper Río Caqueta, into the Río Guaviare and Río Vaupés. Although there are some indications supporting this scenario presented by WISE (2011b), there is currently no concrete evidence – just like for any possible alternative propagation-hypotheses. Contrary to the first appearance, following this argumentation, the collecting site of A. sp. "Diamond-band" unfortunately cannot give any further indication for clustering the species with one or the other of the two species groups.

Apistogramma sp. "Diamond-band", female. In "Diamond-band"-Apistogramma sometimes a turquoise shimmering band is visible in the dorsal too, that however, unlike that of A. sp. "Mitu", increasingly loses its sharp border towards the front.

Depending on how accordance and differences to the A.-macmasteri- and A.-alacrina-group gathered here may be evaluated, one may certainly come to different results concerning the systematic position of the species. Concluding, however, an affiliation to the A.-alacrina-group seems very unlikely, since only the mood dependent similarity of the lateral band of A. sp. "Diamond-band" and A. sp. "Mitu" points towards it. It seems more plausible that A. sp. "Diamond-band" either belongs to the A.-macmasteri-group, or represents a sister group of the A.-macmasteri-group. If, as suggested by MILLER & SCHLIEWEN (2005), the A.-macmasteri- and A.-alacrina-groups are actually in a sister group relationship to each other, a (then possibly even basal) sister group relationship of A. sp. "Diamond-band" to both (i.e. to the A.-macmasteri- and A.-alacrina-groups) would also be conceivable. Which of these scenarios actually applies, or whether A. sp. "Diamond-band" has to be assigned to yet another systematic group within the genus Apistogramma, cannot and should not be further discussed here. In the end, judging this will only be possible by means of comparative studies of the genome, as have already been undertaken for some of the Apistogramma species (TOUGARD et al. 2017). In any case, we can look forward to the further results.

Finally it remains to express our hope that it will be possible to ensure a wider distribution of this systematically interesting but quite demanding little species among enthusiasts of the genus in order to establish it permanently in the aquarium hobby.

Acknowledgements

FH would like to thank Tom Christoffersen, Ernst van Genne, Bruno Magis, Daniel Mejia, Yukitoshi Ohnota and Akihiro Shimizu for the additional photo material and a lot of valuable information.

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