Nothobranchius fuscotaeniatus Seegers, 1997

Last updated 21/10/2000

fuscotaeniatus: the name is derived from the Latin words fuscus (dark) and taenium (stripe) and refers to the dark bars across the body of both males and females.

First Description

Seegers, L. (1997): "Description of Nothobranchius fuscotaeniatus new species"; Aqualog; Killifishes of the World; Old World Killis II; Mörfelden-Walldorf: Verlag A.C.S. GmBH.; Germany: 12.

Terra Typica

The type locality, which is the locality where the Holotype was collected, corresponds to Seegers' collection site TZ 97/57 {Tanzania: Coast Region; Lower Rufiji drainage: about 2 km south of Ndundu ferry across the Rufiji River, along the road from Nyamwage to Kibiti, collected by L. Seegers on 22 July 1997} was a roadside ditch of about 2-m wide and 10-m length, with a depth of about 60-cm, partly covered by high grasses, especially near the shores, but with some few patches of open water. The fish was mainly found between the grasses. Together with the new species, many N.janpapi Wildekamp, 1977 were collected in addition to some N.lourensi Wildekamp, 1977. No other fish were present. All fishes were in good shape and condition. No water measurements at this locality were taken, but according to Seegers (1997) this type of habitat is usually characterised by very soft water with a low amount of dissolved salts and a pH of about 7 to 7.2. Seegers assumed that the species would also occur in other seasonal habitats within the lower Rufiji River drainage system. His assumption was based on the distribution pattern observed from the syntopically living Nothobranchius species: N.lourensi and N.janpapi.

Figure 1: Collecting sites of N.fuscotaeniatus by Seegers [1] and Watters et al. [2]

Watters, Wildekamp & Cooper had however already collected this new species in late May 1997 [two months earlier than Seegers] near the village of Kitonga. They assigned it the provisional name of N. sp. "Kitonga north TAN 97/9". Together with the new species, they also collected from the same locality N.lourensi and N.janpapi Kitonga north TAN 97/9. All three populations were introduced into the hobby.

Meristic & Morphometric Data

Description measurements for N.fuscotaeniatus [After L. Seegers, 1997].

As percent of Standard Length (SL)

Measurements

Variation

Mean values

Holotype

TL

119.9-130.7

126.1

127.2

Body depth

26.6-32.3

29.3

30.5

Body width

11.6-23.4

14.8

11.8

Head length

32.4-36.3

34.9

35.6

Pectoral fin length

16.3-21.5

19.6

21.5

Pelvic fin length

8.0-12.3

10.8

9.7

Caudal peduncle length

19.7-23.9

21.8

21.8

Caudal peduncle depth

12.7-18.3

15.4

14.5

Predorsal length

54.6-61.3

58.7

52.0

Prepelvic length

42.8-52.6

49.2

50.2

Pre-anal length

52.7-65.4

60.9

56.8

As percent of Head Length (HL)

Measurements

Variation

Mean values

Holotype

Head width

52.7-64.8

58.9

51.7

Snout length

19.6-27.0

23.8

24.6

Eye diameter

25.3-33.0

30.2

27.1

Interorbital distance

40.7-48.3

44.2

40.7

Length of pectoral fin

45.5-62.6

56.1

60.2

Length of pelvic fin

22.5-34.5

30.8

27.1

Ray counts

Number of rays

15

16

17

26

27

28

Mean

Dorsal fin rays*

8

1

 

 

 

 

16

Anal fin rays*

 

1

8

 

 

 

17

Scales in longitudinal line*

 

 

 

2

6

1

26.9

(*Figures given indicate number of specimens measured)

Seen from the side, the body is relatively deep and rhombic, the deepest part lying between the dorsal and anal fin origins which are placed in opposition to each other. The head is acute and the back is straight from the dorsal origin to the snout. Pelvic fins are small, dorsal and anal fins relatively deep, especially the latter. The distal margin of the anal fin is straight and not convex as in most other species.

Synonyms

N. spec. "Kitonga" north TAN 97/9 Watters, Wildekamp and Cooper, 1997

Holotype

ZMB 32.781, male, 33.1 mm from snout to caudal origin (=Standard length: SL) and 42.1 mm from snout to end of caudal fin (=total length: TL). Tanzania: Coast Region; Lower Rufiji drainage: about 2 km south of Ndundu Ferry across the Rufiji River along the road from Nyamwage to Kibiti, collected by L. Seegers on 22 July 1997. Collection code TZ 97/57.

Paratypes

ZMB 32.782,3 males, 25.1-31.3 mm SL and 30.1-39.3 mm TL and ZMB 32.783, 6 females, 25.1-28.1 mm SL and 31.1-35.0 mm TL. Collected together with the Holotype.

Size

Males can reach a length of about 45-mm, females remain on the average somewhat smaller, they can reach some 40-mm.

Code

FUS

Distribution & Habitat

B. Watters, R. Wildekamp & B. Cooper first collected the new species in late May 1997. They assigned it the provisional name of N. spec. "Kitonga" north TAN 97/9.

On the 22nd of July 1997, Seegers collected the same species at locality code TZ 97/57, {Tanzania; Coast Region; Lower Rufiji drainage; about 2-km south of Ndundu Ferry across the Rufiji River along the road from Nyamwage to Kibiti}. This was the only location where Seegers collected it, but he supposed that the species would also occur in many other seasonal habitats within the lower Rufiji River drainage system. This assumption is based on the distribution pattern observed from the syntopically living Nothobranchius species: N.lourensi and N.janpapi.

Watters (1998) stated that both the Seegers TZ 97/57 and the Watters, Wildekamp & Cooper Kitonga north TAN 97/9 fish were issued from the same pool, the first was collected in late July 97, the second in May 97. However, according to available maps of Tanzania, the Kitonga locality is situated much more north, close to the Mbezi River, whilst the Ndundu ferry crossing locality is situated much further south, on the Rufiji River. Some further clarifications on the exact collecting sites of N.fuscotaeniatus are thus required as several interpretations are possible, amongst which:

  1. N.fuscotaeniatus is found in two distinct river drainage systems [Mbezi and Rufiji] and does thus not originate from the same pool as stated by Watters (1998) or;
  2. another Kitonga locality must exist 2-km before the Ndundu ferry crossing over the Rufiji River [not found on most maps],
  3. because of some rivalry between both groups of collectors and the rush to publish a description of the new species, one group has incorrectly reported the collection site;

It is therefore considered important to breed both populations in allopatric conditions [separated] until this point can be clarified.

History

L. Seegers describes the discovery of N.fuscotaeniatus in an article published in DATZ (1998). He considers it to be the result of a lucky day. Coming from a collecting trip in southern Tanzania, and because the first part of his mission had been more productive than anticipated, he could spare one day. He therefore decided to spent some time in the Selous Game Reserve and photograph some African wildlife. In order to reach the lodge, coming from the south, one has to cross the Rufiji River either at Ndundu along the lower-river or about 60-km more stream upwards at Utete. As on arrival at the crossroad, the day was already fairly advanced and because he could not reach the ferry at Ndundu in time, he decided to make the crossing at Utete; pass the night there and continue the journey, first thing next morning.

The local guesthouse in Utete was still in the same shape as 15 years ago when Seegers used the facility for the first time. Even next to the river, there was still no running water to change the water of the fish. But by daybreak, it appeared that the smaller ferry at Utete was out of order. Seegers had therefore to travel back the 60-km to Ndundu, make the crossing there and, over a longer side road over Kibiti, reach the opposite side of the river at Utete and progress stream upwards along the northern bank, in order to enter the Selous Game Reserve. This detour added some 150-km of extra bad road to the trip.

Along the road he discovered in a pool a trio of N.eggersi "red". Until then, the red form of N.eggersi had only been known from the vicinity of the Rufiji River Camp in the Selous Game Reserve. Seegers collected it (TZ 97/55) some 100-km downstream of the initial collecting site. The male distinguishes itself from the former population by a more pronounced golden-bronze tone over the body.

At Nyamwage, the road to Ndundu makes a bend to the north. This road is at times in very bad shape. Left and right there are numerous rice fields as well as other smaller and larger areas covered with water. The road follows large road-ditches dugout at construction time. It became apparent to Seegers that he was approaching the river and that he was getting to the onset of the Rufiji River delta. It was impossible to fish all the numerous pools and in addition the road to the Selous Game Reserve was still long. Therefore Seegers fished in only some pools. This yielded some interesting species amongst which some Nothobranchius.

One final trial was made in a 2 x 10 m rest-pool along the road (location TZ 97/57). The shores of the pool were covered in high grasses with the middle somewhat open. In the deepest part, the water level reached some 60-cm. In the mid-day heat, Seegers swept his net unpurposely through the water and caught a poorly coloured female Nothobranchius. As it could not concern the widespread N.melanospilus, he got interested again and swept through the water once again. This time he caught N.janpapi, in which he was not interested, as it is almost as widespread as N.melanospilus in the area. At the third trial he obtained a male of the unknown Nothobranchius species. In the midday sun, the fish lighted bleu-green with some red-brown transversal bands around the body.

More fish had to be caught in order to find the appropriate female. The next caught fish was again a male but this time it belonged to N.lourensi. Females of the latter species are also colourless, which raised the question as to which species the first female belonged to. Therefore more colourless females were caught but at first, no distinction could be made between them. Finally Seegers caught a female, which he had not seen before and which resolved his identification problem. This female was also blue-greenish, but not as pronounced as in the male. And she had also distinguishable red-brown circular stripes along the body.

Until them no Nothobranchius species was known in which females display colours and stripes. It belonged however clearly to the female gender and to a new species. The colourless females all belonged to N.lourensi.

Luckily all fish were in good health when caught and could easily be prepared for the onward journey. Remarkably, no other fish species could be found, not even the very widespread N.melanospilus, in this cut-off part of the road-ditch. After having packed the fish properly, the journey to reach for the ferry over the Rufiji River was continued. Only some 2-km further away, the huts and shops with goods on offer for travelers, started. Two hours later, Seegers found himself on the other side of the Rufiji River. In the end, all fish arrived alive and well in Germany.

According to Seegers (1998), N.fuscotaeniatus can be considered as a rough breed between N.rachovii (body colour) with N.taeniopygus (black tail fin), whereby the form of the tail fin received a light touch of N.janpapi. N.fuscotaeniatus is of course not as closely related to these three species as indicated.

This species is remarkably one of the rare species without red in body coloration and in the tail fin. In the tail fin, the first transversal bands located before the black marginal band are often variable; in some specimens it can be yellowish, in others bleu-green as those on the body. Interesting is also the changing body coloration. Depending on the incoming light, males' light-up green or deeper blue. Especially interesting are also the clearly coloured and banded females, which clearly makes it a distinct species within the Nothobranchius group.

Description

This is so far the only known species of the genus in which males display an intense deep blue-green ground colour with no red neither on the body nor in the fins and in which the females have a similar (although somewhat more subdued) colour pattern than in males. No other Nothobranchius is known in which the females show distinct bars across the body. The colour pattern is unique in the new species.

In the male, the ground colour is of a bluish-green, slightly lighter towards the belly. The back and upper head are brown. About 9-10 bars which are reddish-brown can be seen on the flanks, they may even continue on the dorsal and the proximal half of the anal fins. Both fins are edged with white and have black submarginal bands in its hinder parts which are not sharply delimited. The caudal fin is black in its posterior third; proximally a narrow yellow or greenish band is followed by a reddish band of about the same width. This again is followed proximally by a narrow blue-green and a brown band, the caudal peduncle is green with some dark maculae [spots].

The females have a colour pattern which is very similar to that of the males.

Breeding & Maintenance

N.fuscotaeniatus can already be kept and bred on ordinary tap water with a pH of about 7-8 and a total hardness of around the 11 GDH. Maintenance temperature need preferably be in the vicinity of 22-24C during the day and should be allowed to drop at night to around 20C. After a week of spawning, the peatmoss with the eggs {1.5 mm in size and transparent but slightly brownish are not difficult to spot} is removed, slightly pressed and dried for a few days; then placed into a plastic bag/box, which is then sealed, keeping at least 3/4 of the volume filled with fresh air. The moisture content of the peatmoss containing the eggs should not be allowed to fluctuate too much during incubation. The plastic containers are kept in a dark place were the temperature will be maintained around 22-24C. The incubation time depends on the storage temperature. Good hatches will usually be possible if temperatures are between 20 to 26C {65 to 80F}

All further steps are now a question of patience. The incubation time of N.fuscotaeniatus eggs last about 2.5 to 3 months. Hatching the fry happens by pouring either aged or fresh water onto the peatmoss containing the eggs. The hatching water should however be chilly, having a temperature between 16-18C. The addition of salt {1 teaspoon of salt per liter water} will help fight velvet disease and increase the longevity of the baby brine shrimp that one will add as feed.

The water layer which comes to lay above the peatmoss at hatching time can easily be 7-8 cm deep. With such a water depth, I have had good hatching results after between 1 to 12 hours immersion. This large volume of water renders faster water changes superfluous and dissolves to a greater extent any salt and waste products. In addition, at the bottom were the eggs await hatching, the oxygen shortage by which the developed fry can break out though the eggshell, is created at a much faster paste. The not entirely developed embryo's remain however quite in their resting stage.

Rearing of the fry usually does not cause any further problems. The small fry grows relatively slowly and after 2 to 2.5 months the first ones become sexually mature.

As spawning substrate one should foresee a box wherein a 10-mm thick layer of peatmoss can be introduced. This device helps, to limit the use of peatmoss to a strict minimum, to concentrate the eggs and to avoid contamination of the eggs with waste products.

Because of the high metabolism of N.fuscotaeniatus it is absolutely necessary to provide, on a daily basis, strong and sufficient feeds as otherwise the fishes will be fading away rather rapidly.

Seegers (1998) described the reproduction as follows: N.fuscotaeniatus being a seasonal fish and a bottom layer, the development time of eggs kept in relatively warm conditions was only 8 weeks. During the reproduction act, the male approaches the female and leads her towards the bottom, keeping contact through his chin with the back of the female's head and neck region. On the bottom, the female is laterally surrounded with both the dorsal and anal fins. For her part, she bends her anal fin in a tubular shape in order to lay one egg into the bottom. In a final synchronised push, the egg is pushed deeper into the bottom soil. At times, it can be observed in N.fuscotaeniatus that eggs are laid in the open water but this behaviour can also be observed in other Nothobranchius species. Parents, as opposed to what can be seen in N.melanospilus and N.elongatus, are not often eating eggs.

Bibliography