New fossil cichlid from the middle Miocene of East Africa revealed as oldest known member of the Oreochromini - PubMed (original) (raw)
New fossil cichlid from the middle Miocene of East Africa revealed as oldest known member of the Oreochromini
Stefanie B R Penk et al. Sci Rep. 2019.
Abstract
A new genus and species of fossil cichlid fishes of middle Miocene age (12.5 Ma) is described from the Ngorora fish Lagerstätte (Tugen Hills, Kenya) in the East African Rift Valley. Parsimony analysis of morphological characters using published phylogenetic frameworks for extant cichlids combined with the application of a comprehensive best-fit approach based on morphology was employed to place the new fossil taxon in the phylogenetic context of the African cichlids. The data reveal that the fossil specimens can be assigned to the tribe Oreochromini within the haplotilapiines. †Oreochromimos kabchorensis gen. et sp. nov. shows a mosaic set of characters bearing many similarities to the almost pan-African Oreochromis and the East African lake-endemic Alcolapia. As the striking diversity of present-day African cichlids, with 1100 recognised species, has remained largely invisible in the fossil record, the material described here adds significantly to our knowledge of the Miocene diversity of the group. It effectively doubles the age of a fossil calibration point, which has hitherto been used to calibrate divergence times of the East African cichlids in molecular phylogenetic investigations. Furthermore, the comparative dataset derived from extant cichlids presented here will greatly facilitate the classification of fossil cichlids in future studies.
Conflict of interest statement
The authors declare no competing interests.
Figures
Figure 1
Simplified composite tree showing recently proposed phylogenetic relationships among the non-haplotilapiine Pseudocrenilabrinae and the haplotilapiines (yellow box). In addition, the names of the genera belonging to the Oreochromini (blue box) and the names of the tribes involved in the East African Radiation (orange box) are listed. Source of tree topology: Altner et al.; source of phylogenetic data: refs,,.
Figure 2
Geographical map of Eastern Africa illustrating the Western and Eastern branches of the East African Rift System. The red star marks the location of the study area, the Tugen Hills (Baringo County, Central Kenya Rift). Map reprinted from Kiage & Liu (slightly modified), with permission from Elsevier.
Figure 3
Holotype of †Oreochromimos kabchorensis gen. et sp. nov., OCO-2c-1a, b(1). (a1) Articulated skeleton of part, arrows indicates end of longest dorsal fin ray and first tubular scale of the posterior lateral line segment, respectively. (a2) Interpretative drawing of the head; red and blue lines indicate bones best recognisable on part (a1) and counterpart (a4), respectively; dotted lines indicate tentative outline due to preservation. (a3) Close-up of the predorsal region showing imprint of supraneural bone (arrow). (a4) Articulated skeleton of counterpart. (a5) Close-up of lacrimal bone and infraorbital bones 2 and 3. (a6) Close-up of urohyal bone. Scale bars: 5 mm (a1–a4), 1 mm (a5–a6). Photos of a1 and a4 by M. Schellenberger at the SNSB - Bavarian State Collection of Palaeontology and Geology (BSPG). Abbreviations: art, angulo-articular; ch-a, anterior ceratohyal; ch-p, posterior ceratohyal; cl, cleithrum; co, coracoid; den, dentary; ecp, ectopterygoid; fr, frontal; io, infraorbital; lac, lacrimal; le, lateral ethmoid; mx, maxilla; op, opercle; pmx, premaxilla; pop, preopercle; psph, parasphenoid; ptt, posttemporal; qu, quadrate; ra, radial; rart, retro-articular; sca, scapula; sn, supraneural bone; soc, supraoccipital crest; sop, subopercle; sosc, supraorbital canal; sy, symplectic; uh, urohyal; v, vomer.
Figure 4
(a1–a6) Paratype OCO-2a-10a, b of †Oreochromimos kabchorensis gen. et sp. nov. (a1, a4) Articulated skeleton of part and counterpart. (a2) Close-up of the neurocranium showing the putative nuchal hump, scales, and the supraorbital sensory canal (all indicated with arrows). (a3) Reconstruction of the caudal skeleton, dotted lines indicate tentative outline due to preservation. (a5) Reconstruction of the posterior lateral line segment (complemented based on holotype). (a6) Flank scales visible between the neural spines beneath the soft rayed part of the dorsal fin. Scale bars: 5 mm (a1–a5), 1 mm (a6). Photos of a1 and a4 by M. Schellenberger at the SNSB - Bavarian State Collection of Palaeontology and Geology (BSPG). Abbreviations: ep, epural; hp, hypurapophysis; hs, haemal spine; hy, hypural plate; ns, neural spine; ph, parhypural; pu, preural vertebra; un, uroneural; us, urostyle.
Figure 5
Paratypes of †Oreochromimos kabchorensis gen. et sp. nov. (a1–a4) Specimen OCO-2c-4a. (a1) Articulated skeleton, arrow indicates end of longest anal fin ray. (a2) Tricuspid dentary tooth preserved in situ. (a3–a4) Close-up of the caudal skeleton showing typical caudal fin arrangement, although fin rays are slightly displaced due to taphonomy (photo and reconstruction, dotted lines indicate uncertain outline due to preservation). (b1–b3) Specimen OCO-2c-1a, b(3). (b1) Incomplete articulated skeleton of part, arrow indicates end of longest dorsal fin ray. (b2) Close-up of belly scales between pelvic and anal fin. (b3) Caudal fin of counterpart displaying slightly emarginate shape. Scale bars 5 mm (a1,a3,b1,b3), 1 mm (b2), 0.1 mm (a2). Photos of (a1,b1,b3) by M. Schellenberger at the SNSB - Bavarian State Collection of Palaeontology and Geology (BSPG). Abbreviations: ep, epural; hp, hypurapophysis; hs, haemal spine; hy, hypural plate; ns, neural spine; ph, parhypural; pt1, first anal fin pterygiophore; pu, preural vertebra; un, uroneural; us, urostyle.
Figure 6
Maximum crown widths of tricuspid oral teeth of †Oreochromimos kabchorensis gen. et sp. nov. (this study) and recent species of Alcolapia, Oreochromis, Sarotherodon, and Danakilia compiled from the literature (refs, for Oreochromis, Sarotherodon, and Danakilia; Tichy & Seegers for Alcolapia). Outer-row teeth (n = 11) indicated with unfilled triangles in a black frame, inner-row teeth (n = 30) indicated with filled triangles; colours indicate taxa. Trend line for outer-row teeth in pink, trend line for inner-row teeth in grey. Abbreviation: n. for niloticus.
Figure 7
Phylogenetic interrelationships of 17 cichlid ingroup taxa representing the four known subfamilies currently recognised (Etroplinae, Ptychochrominae, Cichlinae, Pseudocrenilabrinae) and the phylogenetic position of †Oreochromimos kabchorensis gen. et sp. nov. (highlighted in bold). This is the strict consensus tree derived from the two most parsimonious trees (MPTs) produced by TNT from the modified morphological data matrix of Stiassny. Tree length (TL) = 35 steps, consistency index (CI) = 0.89, retention index (RI) = 0.94. Bootstrap values from 1000 pseudoreplicates are presented on the branches (values below 50% indicated with “<”).
Figure 8
Phylogenetic interrelationships of 67 haplotilapiine ingroup species from Lake Tanganyika and the phylogenetic position of †Oreochromimos kabchorensis gen. et sp. nov. (highlighted in bold). This is the strict consensus tree derived from the six MPTs produced by TNT from the modified morphological data matrix of Takahashi. TL = 197 steps, CI = 0.42, RI = 0.79. Bootstrap values from 1000 pseudoreplicates are presented on the branches (values below 50% indicated with “<”). Superscript asterisks refer to updated names (based on Catalog of Fishes, Eschmeyer et al.). The valid names and the corresponding names used by Takahashi are as follows: Asprotilapia leptura (as Xenotilapia), Coptodon rendalli (as Tilapia), Perissodus paradoxus (as Plecodus), and Trematochromis benthicola (as Ctenochromis). Abbreviations: EAR, East African Radiation; n., niloticus.
Figure 9
Morphological characters (ranges) of all modern species of the non-EAR tribes, of those EAR tribes in which <5 lacrimal tubules can occur (lineage Pseudocrenilabrus Group included in the tribe Haplochromini), and of †Oreochromimos kabchorensis gen. et sp. nov. Total numbers of species for each tribe were compiled from the literature (see Suppl. Data 3, Table S6, S8). Numbers of total vertebrae (Vt, including urostyle), dorsal/anal fin formulas, scale types, lateral line segments (LL), lacrimal tubules (#Lt), and numbers of supraneural bones (#Sn) are from this study and from literature (see Suppl. Data 3, Table S6). Ordinal numbers of the vertebrae associated with the last dorsal fin spine (VtPtLDs) are from this study (see Suppl. Data 3, Table S9). Values in bold indicate those characters of †Om. kabchorensis and the extant tribes that show overlap.
Figure 10
Flank and belly scales from the recent species of Alcolapia and Pseudocrenilabrus studied here. Scales are shown from the same specimen for each species, except in the case of A. ndalalani, for which flank and belly scales were obtained from different specimens. All scales are from the left body side, except for the flank scales of A. alcalica and P. philander (these scales are mirrored for better comparison). (a) ZSM 041072_2, 59.8 mm SL; (b1–2) ZSM 025618_2, 90.4 mm SL; (c1–2) ZSM 040995_1, 38.7 mm SL; (d1–2) ZSM 041055_3, 36.8 mm SL; ZSM 041055_2, 38.1 mm SL; (e1–2) ZSM 041575, 60.3 mm SL; (f1–2) ZSM 041143_5964, 43.4 mm SL.
Figure 11
Morphological characters (ranges) of all modern species of the Oreochromini and †Oreochromimos kabchorensis gen. et sp. nov., and supraneural bone morphology (left lateral view). Total numbers of species for each genus were compiled from,,–. Supraneural bone morphology and the ordinal number of the vertebra associated with the last dorsal fin spine (VtPtLDs) are from this study. Numbers of total vertebrae (Vt, including urostyle), dorsal/anal fin formulas, and numbers of lacrimal tubules (#Lt) and supraneural bones (#Sn) are from this study (Suppl. Data 3, Table S9) and from the literature (see Suppl. Data 3, Table S7 for references). Values in bold indicate those characters of †Om. kabchorensis and the extant genera that show overlap. Pictures of supraneural bones are based on the following specimens: (a1–2) OCO-2c-1a(1), holotype; (b1–2) ZSM 040956_1; (c1–2) BMNH 1952.2.26.53-72_3; (d1–2) ZSM 041407; (e1–2), (f1–2) ZSM 025618_1, ZSM 025618_3; (g1–2) ZSM 040017_1; (h1–2) SBF 030311_(1); (i1–2) BMNH 1981.8.17.54-74_2; (j1–2) ZSM 029851_4; (k1–2) ZSM 029834_(4); (l1–2) ZSM 029844_(4); (m1–2) ZSM 029836_3; (n1–2) ZSM 029839_3; (o1–2) MRAC-164730-732_(720).
Figure 12
Principal coordinates analysis (PCoA) scatter plot based on eight meristic characters and the number of supraneurals from all modern genera of the Oreochromini (42 species, 181 specimens) and from †Oreochromimos kabchorensis gen. et sp. nov. See Suppl. Data 3, Table S9 for raw data.
Figure 13
Summary of all previously described African and European fossil cichlids of the tribe Oreochromini, and morphological characters differentiating them from †Oreochromimos kabchorensis gen. et sp. nov. Supraneural bone morphology of †Oreochromis lorenzoi and †O. harrisae redrawn from Fig. 3a in Carnevale et al. and Fig. 5d in Murray & Stewart (mirrored). Abbreviations: —, unknown character; #Lt, number of lacrimal tubules.
Figure 14
Morphometric measurements and scale size analyses (double arrows) conducted for this study. (a) Schematic drawing of a generalized cichlid depicting the various head-, body-, and fin-related measurements used to characterise specimens. (b1–2) Drawings of the lower jaw bone (b1) and the upper jaw bone of Haplochromis vonlinnei (b2) in right lateral view, depicting the measurements taken (reprinted from Figs 3 and 6 in Van Oijen & De Zeeuw, with permission from Naturalis Biodiversity Center). (c) Scale surface showing the measurements used to characterise the form of flank and belly scales (right flank scale of Alcolapia ndalalani, ZSM 041055_1). Abbreviations: art, angulo-articular; BL, body length; den, dentary; ED, horizontal eye diameter; H, maximum body height; h, minimum body height; H2, maximum body height at origin of anal fin; HD, head depth; HL, head length; lA, length of anal fin base; lAs1, length of first anal fin spine; lasc, length of premaxillary ascending process; lD, length of dorsal fin base; lDbr, length of soft dorsal fin base; lDsl, length of last dorsal fin spine; lDsp, length of spinous dorsal fin base; lLj, length of lower oral jaw; lpc, length of caudal peduncle; lpmx, length of premaxilla; lVs, length of pelvic fin spine; pD, postdorsal distance; pmx, premaxilla; prA, preanal distance; prD, predorsal distance; pro, preorbital distance; prV, prepelvic distance; rart, retro-articular; SL, standard length; TL, total length.
References
- Eschmeyer, W. N. & Fong, J. D. Catalog of Fishes: Species by Family/Subfamily. Available at, http://researcharchive.calacademy.org/research/ichthyology/catalog/Speci... (2018).
- Berra, T. M. Freshwater fish distribution. (Univ. of Chicago Press, Chicago, Illinois, USA, 2007).
- Brauner CJ, Gonzalez RJ, Wilson JM. Extreme environments: hypersaline, alkaline, and ion-poor waters. Fish Physiol. 2013;32:435–476. doi: 10.1016/B978-0-12-396951-4.00009-8. -DOI
- Murray AM. The fossil record and biogeography of the Cichlidae (Actinopterygii: Labroidei) Biol. J. Linn. Soc. 2001;74:517–532. doi: 10.1111/j.1095-8312.2001.tb01409.x. -DOI
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