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A mouth full! – Apistogramma sp. "D10", a new mouthbrooder from Colombia



The fins of adult males are particularly impressive due to the pattern of iridescent markings. (Photo: Frank Hättich)


(This is an authors' translation of the original German article published in November 2017 in the monthly German Cichlid Society (DCG) journal. Hättich, F. & Kipper, R. (2017): Die Schnauze voll! – Apistogramma sp. „D10“, ein neuer Maulbrüter aus Kolumbien. – DCG-Informationen 48 (11): 242-247.)


With the work of Tom CHRISTOFFERSEN (Larvik, Norway) and Daniel MEJIA (Bogota, Colombia), many new species and forms of Apistogramma have been discovered in Colombia and introduced into the aquarium hobby.
In order to protect the wild populations and the livelihoods of the local fishermen who collect these fishes, no detailed information concerning catch location is provided.1 For this reason MEJIA and CHRISTOFFERSEN have decided to use a naming-scheme for the new forms that in particular doesn’t give away the locational information. Imitating the apparently discontinued DATZ A-number system, the notations ‘D1’, ‘D2’, ‘D3’, etc. are used, where the letter ‘D’ honors the discoverer of most of the fishes, Daniel MEJIA.
One of the most interesting new species is known as Apistogramma sp. ‘D10’, which is the third facultative larvophilous mouthbrooding species within the genus, along with A. barlowi RÖMER & HAHN, 2008 and A. megastoma RÖMER et al. 2017. However, it turned out that the list of mouthbrooding species doesn’t end here. Another new species, now known as A. sp. ‘D50’, was discovered by MEJIA in the summer of 2016 in the upper Rio Vaupés drainage, which also turned out to be a facultative larvophilous mouthbrooder (RÖMER, in prep.)

Highly aggressive male with a sooty-dark belly-blotch and a faded lateral band in the front third of the body. (Photo: Frank Hättich)

Adult animals rarely show such a pronounced lateral spot as this female does. (Photo: Frank Hättich)







Habitat

In November 2015, MEJIA found A. sp. ‘D10’ in a small black water stream belonging to the Rio Caquetá system. A. sp. ‘D10’ were found in sunny and shallow areas within the stream, where leaf litter and aquatic plants offered plenty of hiding places. The substrate in this habitat was fine white sand.
The largest specimens collected were about 5 cm in total length, but most were significantly smaller.
Besides A. sp. ‘D10’, another species of Apistogramma, namely A. cf. personata, was found in the same vicinity. Unfortunately, water parameters were not measured at this collecting site, but similar neighboring black water streams possessed a pH below 5 and extremely low electrical conductivity as expected of this type of water. Although these nearby streams were searched, A. sp. ‘D10’ was not found.
Besides the two Apistogramma species, fishes from many other genera were collected, e.g. Rivulus POEY, 1858, Copella MYERS, 1956, Pyrrhulina VALENCIENNES, 1846, Erythrinus SCOPOLI, 1777, Poecilocharax EIGENMANN, 1909 and Hoplias GILL, 1903, as well as some not further identified knifefish.

The strongly elongated soft parts of anal and dorsal fin as well as the red seam in the latter are exceptional among females of the genus. (Photo: Frank Hättich)

Dominant male with mood dependently vanished lateral band. (Photo: Roland Kipper)







Maintenance, Breeding and Behavior

Maintenance and breeding of A. sp. ‘D10’ is achieved in soft and acidic water with a pH of 5.5 and an electrical conductivity of 100uS/cm.
However, since it is a black water species, enriching the water with humic substances (e.g. using peat filtering, leaves of almond, oak or beech etc.) is suggested.
If one further more provides the animals with a well structured tank, an assortment of hiding places, a smooth fine-grained sand substrate, as well as a varied diet, it should not take long for them to reproduce.
Unfortunately, there is little information about their courtship and spawning behavior. However, the courtship behavior known from male A. barlowi involving display with widely opened mouth and the intake and chewing of sand that finally is sifted through the gills (BREEZE 2007) is not shown by A. sp. ‘D10’. But Uwe RÖMER (pers. comm.) observed a different courtship behavior that has not been observed before in any Apistogramma species. Initially, the male placed himself in front of the female with his body in an upright position (head up) and presented the ventral part of his belly. From there, he swam towards the female while jerking his head.
Unfortunately, it hasn’t been possible to observe the further course of courtship.
Interestingly, one of the authors (FH) observed such ‘tail-standing’ behavior during the courtship of the other recently discovered Colombian mouthbrooder A. sp. ‘D50’.
As usual for Apistogramma, A. sp. ‘D10’ prefers caves or other hiding places as spawning sites. The entrances of these hiding structures are often secured against potential intruders by sand piles created by the females.
So far, spawns of up to 40 eggs have been observed, a remarkable number for a mouthbrooding species such as A. sp. ‘D10’.

Slightly aggressive mouthbrooding female. (Photo: Frank Hättich)

Aggressive female shortly before an attack. (Photo: Roland Kipper)





The larvae hatch after around three days at a water temperature of 25 °C.
From this point onwards, different brooding strategies employed by the female have been observed.
The first was the well known cave brooding method in which the larvae stay within the original spawning site or are
(at times) moved to other caves by mouth.

Portrait of a mouthbrooding female carrying about 40 larvae in her bulging mouth. (Photo: Frank Hättich)

Besides this, different degrees of larvophilous mouthbrooding have been observed.
Some females take the broodcare duty so seriously that they keep the larvae in their mouth almost constantly from the hatching of the larvae to the free swimming of the fry while not eating anything during this period.
As in A. megastoma, males have not been observed to employ the mouthbrooding strategy so far.
In A. barlowi, males at times do participate in mouthbrooding, but it only takes place under specific circumstances (RÖMER 2008).
Until more observation is completed, it therefore can’t be concluded with certainty that A. sp. ‘D10’ is in fact a purely maternal mouthbrooder.
What is certain is that A. sp. ‘D10’ can modify their brooding strategy, probably in order to adapt it to environmental conditions (e.g. level of threat by potential fry predators, substrate, strength of the water current, etc.). Like A. barlowi and A. megastoma, A. sp. ‘D10’ might be a species that is still at the early stages of becoming a fully specialized larvophilous mouthbrooder and is thus still able to adapt it’s brooding behavior to the environmental circumstances.
In this context, an observation by Ray BLACKBURN (Liverpool, England) who successfully bred the species several times is worth mentioning. His female kept the fry in her mouth regularly and for longer periods of time even after they first went to the free swimming stage. On one occasion, the female held fry in her mouth that had been at the free swimming stage for almost three weeks.
If this behaviour will be confirmed by observations on other females, A. sp. ‘D10’ would be the first species of the genus performing mouthbrooding after the fry have already been free swimming.

Male during threat-display in lateral position. A behavior so far merely known from few Apistogramma species.
(Photo: Frank Hättich)

It’s not merely the courtship and brooding behavior of A. sp. ‘D10’ that is interesting. In their threat-displays too, they show a special behavior already known from some other species though (KOSLOWSKI 2002). Starting from the usual lateral threat-display in which all fins are widely spread and the caudal fin is waved (or ‘slapped’) in order to impress the opponent, A. sp. ‘D10’ may rotate their body 90° around the longitudinal axis bringing it into a lateral position. In this position, the flanks parallel the ground and the rivals frontally oppose each other with closed or slightly opened mouths, while their heads may perform jerking movements.




Phenotypic Features and Sexual Dimorphism

A. sp. ‘D10’ has a slightly elongate and moderately deep body. With 9 cm being the total length of the largest known male and 6.5 cm in females, it is one of the larger representatives of the genus. Both sexes have a disproportionately large head that however isn’t as large as in A. barlowi and A. megastoma. The mouth and lips are less pronounced and less padded than in the other two species too. The base color of the body is a light often yellowish shade of beige. In males it can also be a light rosy color. Moreover, males have a bluish or greenish shine that is often laid over the base color of their bodies.

Male of A. sp. ‘D10’ in threat-display. (Photo: Frank Hättich)

Adult males show conspicuous markings consisting of shiny blue-turquoise stripes and large red-orange spots and wormlike markings that can cover the complete lower half of the head.
A. sp. ‘D10’ usually possesses three infraorbital pores situated in a curved position below each eye. In some cases, it can also appear four on one or both sides of the head (RÖMER, pers. comm.).2 
If a pronounced postorbital stripe is visible, it merges continuously with the immediately adjacent lateral band that always possesses a zig-zag boundary. It reaches to the end of the seventh vertical bar and generally touches the round to vertically oval, but often also irregularly shaped, caudal spot there.
Depending on mood, the lateral band presents itself in different shapes. It can consist of aligned laterally rounded diamonds or laterally compressed hexagons, the interior of which can be colored either light or dark. However, it can also be partly or completely zig-zag shaped. Altogether, it strongly resembles the lateral band of the species related to A. macmasteri KULLANDER, 1979.

Aggressive male showing a sooty belly-blotch, as well as darkened lips and forehead. (Photo: Frank Hättich)

Subadult specimens of A. sp. ‘D10’ often show a pronounced lateral spot, whereas adult animals rarely display this feature.
In aggressive mood, the postorbital stripe and the first part of the lateral band often vanish completely while the lips and forehead take on a dark color.
In males, a large sooty blotch can appear on the belly, which is often seen in relatives of A. macmasteri but isn’t restricted to these. A comparable belly-blotch can also be seen e.g. in A. megaptera SALAZAR & LASSO, 2012, A. cf. personata, and in a scientifically undescribed form related to A. agassizii (RÖMER, pers. comm.).
  
The dorsal fin of females is truncated, but the first few membranes can be slightly pointed.
In adult males, the membranes are often pointed up into the posterior part of the dorsal. In large males, the membranes even can be distinctly elongated, particularly in the anterior and middle part of the fin. In addition, the dorsal fin in adult males shows a remarkable pattern of iridescent turquoise spots and stripes.
Interestingly, the soft parts of the dorsal and anal fin are strongly elongated not only in males but also in females. In fact in females they are almost as long as in males, which to our knowledge, isn’t the case in any other Apistogramma species.

           

Young male with mostly zig-zag shaped lateral band searching
for food. (Photo: Frank Hättich)

Male with pronounced black coloration at the frontal edges of the ventral fins and bluish-greenish body-sheen. (Photo: TomC)




The ventral fins are also strongly elongated in both sexes, although there is a noticeable lack in length in females when compared to males.
The caudal fin is rounded. In males, it possesses slight iridescent bluish vertical stripes/dotted lines whereas that of the females is not patterned.

In aggressive mood the caudal fin can take on a sooty-dark hyaline coloration. (Photo: Roland Kipper)

As in most Apistogramma species, the body and fins of females that are ready to spawn or even more while actually brooding take on an intense yellow coloration in which the black markings stand out particularly well.
Brooding females in neutral mood show a continuous deep black lateral band, a caudal spot, and pronounced dorsal spots but no lateral spot. Due to the aggressive mood while brooding, the lateral band is often only shown in the second half of the body. Brooding females of A. sp. ‘D10’ show no markings on the ventral part of abdomen, chest, or throat, as is common for many species of the A.-macmasteri-group as well as for A. barlowi with their distinct breast-band.
A. sp. ‘D10’ exhibits pronounced sexual dimorphism. With a total length of 6.5 cm, females can become quite large. But in contrast to the males, they are still significantly smaller. And among other things they don’t show a pattern in the caudal fin, colored markings on the head, pattern of iridescent spots in the dorsal and less bluish colored ventral fins as in the males. However, the differences in size and shape of the fins (to those of the males) are smaller than in many other species of the genus.


Remarks about their Systematic Position

The following considerations are based on the classification of the genus Apistogramma into lineages, species-groups, and complexes, according to the systematics proposed by Mike WISE (2011).

Adult male showing an intense rosy body color.
(Photo: Frank Hättich)

Because of the particular combination of features shown by A. sp. ‘D10’, it is difficult to assign them to any of the existing circles of relationship within the genus. The zig-zag lateral band and the sooty belly-blotch are distinct features, that could lead one to believe that they belong to the A.-macmasteri-group within the A.-regani-lineage. However, their lateral spot and the reduced number of infraorbital pores block their allocation to any species-group within the A.-regani-lineage, because two of the pivotal characteristics that delineate the A.-regani-lineage from the other three lineages – the A.-trifasciata-, A.-pertensis- and A.-diplotaenia-lineage – are the possession of all four infraorbital pores and the absence of a lateral spot. Thus an assignment to the A.-macmasteri-group as well as to the A.-regani-lineage is not possible with the current understanding of the latter.
In this context, the other mouthbrooding species, A. sp. ‘D50’, discovered by MEJIA in the upper Rio Vaupés, is worth mentioning. Besides similarities, particularly between younger specimens of A. sp. ‘D10’ and A. sp. ‘D50’, the entire appearance of the latter (not merely the lateral band and the belly-blotch) is very much reminiscent of species in the A.-macmasteri-group. However, like A. sp. 'D10', they also possess a lateral spot (their number of head pores is not known at the moment).

          

Aggressive male of A. sp. ‘D50’. The similarity to species of the
A.-macmasteri-group is evident. (Photo: Frank Hättich)

Female of A. sp. ‘D50’ caring for her free swimming fry.
(Photo: Roland Kipper)



Thus the existence of this species could be another indication that the above mentioned characterization of the A.-regani-lineage (that contains almost half of all known Apistogramma species and forms) might be untenable.
Another speculative possibility shall not be kept unmentioned, namely the existence of a to date unrecognized sister-lineage of the A.-regani-lineage, in which the ancestral lateral spot has been preserved (contrary to the A.-regani-lineage) and to which A. sp. ‘D50’ as well as A. sp. ‘D10’ might belong.
Let us now return to the task of classifying A. sp. ‘D10’ according to the systematics in it’s currently existing form. According to this systematics the lateral spot and the reduced number of infraorbital pores point towards the A.-trifasciata-lineage (see WISE 2011). As moreover the particular combination of features shown by A. sp. ‘D10’ in all probablity rule out the A.-pertensis- and A.-diplotaenia-lineage, the A.-trifasciata-lineage is in fact the most probable option for the allocation of A. sp. ‘D10’ within the framework of the currently existing systematics.
However, there is no species-group within the A.-trifasciata-lineage into which A. sp. ‘D10 would easily fit. Though there is a general resemblance to the species of the A.-atahualpa-group – the group that contains the two mouthbrooders A. barlowi and A. megastoma – the assignment to this group isn’t really convincing. Thus if A. sp. ‘D10’ should in fact belong to the A.-trifasciata-lineage, it might be a representative of a currently unrecognized new species-group within this lineage.
Which of these partly speculative considerations on the relatedness of A. sp. ‘D10’ within the genus might be accurate, can’t be further resolved here. Fortunately, comparative genetic studies that might provide us with more information about the systematic position of A. sp. ‘D10’ have already been started (RÖMER, pers. comm.).
   
In closing, we would like to express our hope that it will succeed to spread this beautiful and systematically interesting species, that moreover shows some exciting behaviors, among many dwarf cichlid enthusiasts in order to permanently establish it in the hobby. 


Acknowledgements

We would like to thank Ray Blackburn, Tom Christoffersen, Daniel Mejia and Uwe Römer for their support in providing plenty of information and photo material. We would also like to thank Volker Bohnet and Uwe Römer for proofreading earlier drafts of the the German text, and Shane Puthuparambil for his help with the English version.

Sources

BREEZE, M. (2007): Apistogramma sp. ‘Maulbrüter’, the one and only. Cichlidae: The Journal of the British Cichlid Association, 28 (5): 5 –15.
KOSLOWSKI, I. (2002): Die Buntbarsche Amerikas, Band 2: Apistogramma und Co. Eugen Ulmer, Stuttgart: 318 Seiten.
RÖMER, U. & I. HAHN (2008): Apistogramma barlowi sp. n.: Description of a new facultative mouth-breeding cichlid species (Teleostei: Perciformes: Geophaginae) from Northern Peru. Vertebrate Zoology 58 (1): 49-66.
WISE, M. (2011): A Description of Apistogramma Species-Groups, 2011.
Available at: [www.apisto.sites.no/page.aspx?PageId=116].

___________________________
1 However, for scientific purposes all geographic information is made available.
2 That the number of infraorbital pores can by way of exception differ on the sides of the head of a single specimen is a
well known phenomenon (KOSLOWSKI 2002) that sometimes also occures e.g. in A. velifera STAECK, 2003 (WISE 2011).