Compiled and Edited by:
Nancy B. Simmons and Andrea L. Cirranello
American Museum of Natural History

Your search for Nycticeinops resulted in 3 species-level matches:

Nycticeinops Hill & Harrison, 1987. Bull. Br. Mus. Nat. Hist. 52: 254.

Nycticejus schlieffenii Peters, 1859

Nycticeinops eisentrauti (Hill, 1968).
Bonn. Zool. Beitr. 19: 45.
Eisentraut's Pipistrelle

Pipistrellus eisentrauti

Cameroon, Western Province, Rumpi Highlands, Dikume-Balue

Cameroon

CITES - Not Listed (2023). IUCN - Data Deficient as Hypsugo eisentrauti (2019).

Previously considered a species of Hypsugo, but transferred to Nycticeinops by Hoofer and Van Den Bussche (2003; see also Amador et al., 2016, and see discussion of sequences used in these papers by Hutterer et al., 2019). Transferred to Parahypsugo by Hutterer et al. (2019). Formerly included bellieri (e.g., Koopman, 1989, 1993, 1994), which was considered a synonym of crassulus following Heller et al. (1994), but which is now recognized as a distinct species within Parahypsugo, along with crassulus. Distribution of this species appears to be limited to Cameroon; see discussion in Hutterer et al. (2019).

References:

Amador, L.I., R.L. Moyers Arévalo, F.C. Almeida, S.A. Catalano, and N.P. Giannini. 2016. Bat systematics in the light of unconstrained analyses of a comprehensive molecular supermatrix. Journal of Mammalian Evolution 2016: 1-34. Read abstract.

Heller, K.-G., M. Volleth, and D. Kock. 1994. Notes on some vespertilionid bats from the Kivu region, Central Africa. Senckenbergiana Biologica 74: 1-8. Not available online.

Hill, J.E. 1968. Bats from the Cameroons, with the description of a new species of PipistrellusBonner zoologische Beiträge 19: 43-48. Read article.

Hoofer, S.R., and R.A. Van Den Bussche. 2003. Molecular phylogenetics of the chiropteran family Vespertilionidae. Acta Chiropterologica 5(suppl.): 1-63. Read abstract.

Hutterer, R., J. Decher, A. Monadjem, and J. Astrin. 2019. A new genus and species of Vesper bat from West Africa, with notes on Hypsugo, Neoromicia, and PipistrellusActa Chiropterologica 21(1): 1-22. Read abstract.

Koopman, K.F. 1994. Chiroptera: Systematics. Handbuch der Zoologie, vol. VIII, Mammalia, Part 60. de Gruyter, Berlin: 224 pp. Not available online.

Koopman, K.F. 1993. Chiroptera.  Pages 137-241 In D.E. Wilson and D.M. Reeder (eds.) Mammal Species of the World. A Taxonomic and Geographic Reference. Washington, D.C.: Smithsonian Institution Press. Not available online.

Nycticeinops macrocephalus (Hutterer & Kerbis Peterhans, 2020).
Lynx, n.s. 50: 53.
Big-headed Pipistrelle

Democratic Republic of Congo, 4 km SW of Talama, Kabogo Forest

Democratic Republic of Congo, Rwanda, possibly Somalia and Kenya

CITES - Not Listed (new species). IUCN - Not Evaluated (new species).

Populations in Kenya and Somalia remain unstudied and these may represent an additional species (Hutterer and Kerbis Peterhans, 2019). Although there is an online version of this publication, and the paper and the date for the species epithet give the date of publication as 2019, the paper appears to have been published in print in 2020. This is the correct date for the species epithet, even if the online version appeared in 2019, since the authors did not provide evidence of a ZooBank registration for the species epithet in the paper.

References:

Hutterer, R., and J. Kerbis Peterhans. 2020 [dated 2019]. A further new species of vesper bat from Central Africa (Chiroptera: Vespertilionidae). Lynx, n.s. 50: 51-59. Read article.

Nycticeinops schlieffenii (Peters, 1859).
Monatsb. K. Preuss. Akad. Wiss. Berlin 1859: 224.
Schlieffen's Twilight Bat