Revalidation and Redescription of “Lacustricola” chobensis (Fowler, 1935) and Description of a New Miniature Species of “Lacustricola” from Southern Africa (Cyprinodontiformes: Procatopodidae)
The “Lacustricola” hutereaui species complex is herein defined by the possession of banded dorsal, anal, and caudal fins in males and also by the pointed premaxilla ascending process, in which the premaxilla medial surface is slightly convex. “Lacustricola” pygmaeus, new species, known from the Okavango, Cuando, and upper Zambezi Rivers, is distinguished from the other species belonging to the “L.” hutereaui species complex by the following exclusive character states: an inconspicuous reticulate pattern on scale margins (vs. conspicuous); banded anal, dorsal, and caudal fin in females (vs. hyaline); faint bands in the middle rays of caudal fin in males (vs. conspicuous bands); rounded caudal fin in males (vs. slender); bright green-blue color in some of the flank scales (vs. absent); quadrate posterior margin with a deep concavity (vs. convex or about straight); and first dorsal-fin ray inserted in a vertical to second and third anal-fin ray (vs. fourth to eighth). Additionally, other morphometric, meristic, and osteological characters in combination proved to be useful in distinguishing the new species. Through the analysis of type material and recently collected specimens, the little known species “L.” chobensis is considered as a valid species and redescribed. It is easily distinguished from the other species belonging to the “L.” hutereaui species complex by a combination of external morphology, osteology, and coloration pattern characters. Comprehensive information on the osteology and external morphology of topotypes of “L.” hutereaui are presented, and description of coloration in life is provided for specimens from the Ubangui River, in the Central African Republic.
“Lacustricola” chobensis, preserved specimens: (A) male SAIAB 101089, 22.6 mm SL, Boa Fé Lagoon, Okavango River basin, Angola; (B) female SAIAB 200797, 17.5 mm SL, Bwabwata National Park, Okavango River basin, Namibia.
Coloration of “Lacustricola” chobensis in life: (A) male SAIAB 200765, 24.0 mm SL, Bwabwata National Park, Okavango River basin, Namibia; (B) male uncatalogued, Kalimbeza swamps, Namibia; (C) female SAIAB 200765, 19.0 mm SL; same locality as specimen (A).
Lachrymal, jaws, suspensorium, and opercular apparatus. “Lacustricola” hutereaui (MRAC P.182191–205): (A) lachrymal; (B) jaws, dorsal view; (C) jaws, suspensorium, and opercular apparatus, lateral view; “Lacustricola” pygmaeus (SAIAB 204087): (D) lachrymal; (E) jaws, dorsal view; (F) jaws, suspensorium, and opercular apparatus, lateral view. Arrows indicate informative traits: 1.0, posteroventral extension absent; 1.1, posteroventral extension present; 2.0, maxilla sharp ventral process; 2.1, maxilla ventral process greatly reduced, consisting of rounded ventromedial bulge; 3.0, retroarticular smaller than anguloarticular ventral arm; 3.1, retroarticular similar in depth and length to anguloarticular ventral arm; 4.0, quadrate posterior margin convex or about straight; 4.1, quadrate posterior margin with deep concavity. Scale bars = 1 mm.
Cephalic pores and head squamation pattern: (A–B) “Lacustricola” pygmaeus (same pattern is seen in “L.” chobensis); (C–D) “L.” hutereaui.
Pectoral-fin girdle and caudal-fin skeleton, left lateral view: (A, C) “Lacustricola” hutereaui (MRAC P.182191–205); (B) “L.” pygmaeus (SAIAB 204242); (D) “L.” chobensis (SAIAB 66784). Arrows indicate informative traits: 1.0, posttemporal forked; 1.1, posttemporal rod-like; 2.0, cleithrum posterodorsal flap sinuous; 2.1, cleithrum posterodorsal flap rounded. Scale bars = 1 mm.
“Lacustricola” pygmaeus, preserved specimens: (A) holotype, male, SAIAB 204087, 17.1 mm SL, Cuanavale Lake, Okavango River basin, Angola; (B) female, SAIAB 204242, 16.1 mm SL, Salia Kuembo Lake, Okavango River basin, Angola.
(A) Riverine habitat of “Lacustricola” chobensis and “L.” pygmaeus in the Kataba River, upper Zambezi, Zambia (photo: D. Tweddle, 2015); (B) swampy habitat of “Lacustricola” pygmaeus in one of the source lakes of the upper Cuando River, Angola (photo: R. Bills, 2016).
Distribution of “Lacustricola” chobensis based on the SAIAB specimens examined in the present study. The letter (T) refers to type locality.
Coloration in life. (A) “Lacustricola” pygmaeus, male, SAIAB 204242, 15.8 mm SL, from one of the source lakes of the Cuando River, Angola. “Lacustricola” hutereaui: (B) male, SAIAB 78314, 22.5 mm SL; (C) female, 19.4 mm SL; both from Ubangui River drainage, Central African Republic.
Distribution of “Lacustricola” pygmaeus based on the SAIAB specimens examined in the present study. The letter (T) refers to type locality.
Contributor Notes
Associate Editor: R. E. Reis.