THE NOTHOBRANCHIUS SITE

MRAC 97-82-P-22, holotype, male, 21.3 mm SL; Tanzania: Rufiji floodplain: 5.5 km south of Kitonga, pool in a ditch on the western side of the road from the Rufiji ferry to Nyamwage, 08°04.37' S, 39°00.13' E; collected by B. J. Cooper, B. R. Watters & R. H. Wildekamp, 09 Jun 1997 [field code: Kitonga south TAN 97-36].

MRAC 97-82-P-23-26 (4)

Nothobranchius annectens differs from all other species of the N. guentheri species group by a translucent red caudal fin in male, with deeper red upper and lower margins; there is a broad black or dark grey marginal bar to the posterior part of the caudal fin. It is separated from the other species of the group, with the exception of N. guentheri and N. rubripinnis, by a distinct red spot on the male opercle. It is further distinguished from the latter two species by smaller size, greater body depth and male colouration (after Watters et al. 1998).

The male has a red chevron-shaped cross-bar pattern on the posterior part of the trunk from the dorsal fin origin. The female has a dark grey vertical chevron pattern from the dorsal fin origin.

Subgenus: Adiniops

Species group: N. guentheri group

Nothobranchius annectens was established as a species by Watters, Wildekamp & Cooper in 1998, and that status has since been accepted by all authors.

"Tansania, 5.5 km südlich von Kitonga, Tümpel in einem Graben an der westlichen Seite der Straße von der Rufiji-Fähre nach Nyamwage, in der Überschwemmungsebene des Rufiji-Flußes."

[Tanzania, 5.5 km south of Kitonga, pool in a ditch on the western side of the road from the Rufiji ferry to Nyamwage, in the floodplain of the Rufiji (08°04.37' S, 39°00.13' E).]

This species is endemic to freshwater habitats in coastal Tanzania. It is known from seasonal pools and marshes in the drainages of the Ruvu, Ruhoi and Rufiji rivers, and some minor coastal rivers south of the Rufiji, in eastern Tanzania.

3–93 m

Coastal East Africa (564)

Water parameters (Watters et al., 1998):

Water temperature: 25–29 °C

pH: 6.90–7.49

Conductivity: 100–640 µS

Personal observation at collecting sites:

Water temperature: 31.3–31.5 °C

pH: 7.40–8.05

TDS: 70–145 ppm

Conductivity: 140–290 µS

N. melanospilus - 88%

N. janpapi - 85%

N. ocellatus - 29%

N. eggersi - 27%

N. foerschi - 5%

N. flammicomantis - 2%

This species has a semi-annual life cycle.

Embryonic development under captive conditions in peat moss is about two to three months at room temperature.

Maximum size reported: 34.1 mm SL (MRAC 97-82-P-27, male)

Diploid chromosome number 2n = 28, NF = 36, karyotype structure 8m+20st/a (Krysanov & Demidova, 2018).

Diploid chromosome number and karyotype structure unique in the genus.

The specific name is formed from the word annectere (in Latin for join, connect), in reference to the position of this species as a link between Nothobranchius guentheri known from Zanzibar Island and the rest of the species-group living on the mainland.

Near Threatened B1ab(iii)+2ab(iii) (Nagy & Watters, 2019);

Previous assessment: Vulnerable D2 (Hanssens & Snoeks, 2006)

    Watters, B. R., R. H. Wildekamp & B. J. Cooper. 1998. Zwei neue Nothobranchius-Arten aus der Küstenebene Tansanias. Deutsche Killifisch Gemeinschaft Journal, 30 (3): 52–63. [taxonomy as Nothobranchius annectens]

    Nagy, B. & A. Horváth Kis. 2010. Variation in habitat characteristics and the occurrence of Nothobranchius species in seasonal biotopes of Tanzania. Journal of the American Killifish Association, 43 (5): 130–144. [collecting, ecology]

    Nagy, B. 2010. A la recherche de killis sur l’île de Pemba et dans la partie côtière de la Tanzanie. Killi Revue, Killi Club de France, 2010 (5): 3–11. [collecting]

    Nagy, B. & B. R. Watters. 2019. Nothobranchius annectens. The IUCN Red List of Threatened Species 2019: e.T61218A47240568. [conservation]

    Watters, B. R., B. Nagy, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2020. Redescription of the seasonal killifish species Nothobranchius ocellatus and description of a related new species Nothobranchius matanduensis, from eastern Tanzania (Teleostei: Nothobranchiidae). Ichthyological Exploration of Freshwaters, IEF-1149, pp. 1–28. [phylogeny]