Labeo latebra, Moritz & Neumann, 2017
|
publication ID |
https://doi.org/ 10.26028/cybium/2017-411-003 |
|
persistent identifier |
https://treatment.plazi.org/id/37783D19-3E3C-FFFA-9C23-681B4F09FD6E |
|
treatment provided by |
Felipe |
|
scientific name |
Labeo latebra |
| status |
sp. nov. |
Labeo latebra , new species
( Figs 1-7 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 , Tabs I-II)
Material
Holotype. – ZSM 44841, 126.4 mm SL, Sudan: White Nile at Kosti , retrieved from local fishermen deploying gill nets downstream of railway bridge (N13.15° E32.72°), coll. D. Neumann, T. Moritz, A.A. Saadelnour Abdalla, M.A. Abdallah, 15 Apr. 2016. GoogleMaps
Paratypes. – DMM IE/6443 (1), 122.1 mm SL, Sudan: obtained at Central Souq el Samak [fish market] in Khartoum, likely traded from the Sudd-Region , coll . T. Moritz & V. von Vietinghoff, 26 Jan. 2006 ; DMM IE/11232 (1), 77.5 mm SL, Sudan: White Nile, in front of Fisheries Research Centre at Kosti (N13.17475° E32.67077°), coll GoogleMaps . T. Moritz, M. Mertzen, 15 Apr. 2016 ; ZSM 39868 View Materials (3), 83.7- 92.9 mm SL, Sudan: obtained in Central Souq el Samak [fish market] in Khartoum, allegedly traded from Al-Qutaynah (N14.0° E32.4°), White Nile, coll GoogleMaps . T. Moritz, D. Neumann & N. Pöllath, 7 Apr. 2008 ; ZSM 43615 View Materials (1), 109.7 mm, same data as ZSM 39868 GoogleMaps ; ZSM 44712 View Materials (1), 87.5 mm SL, Sudan: White Nile at Al Jabalayn boat landing site (N12.58312° E32.80355°), coll. D. Neumann GoogleMaps , T. Moritz, M. Mertzen, A.A. Saadelnour Abdalla, M.A. Abdallah, 13 Apr. 2016 ; ZSM 44722 View Materials (1), 67.9 mm SL, Sudan: White Nile at Makhaleif village, 10 km south of Al Jabalayn (N12.51908° E32.82493°), coll. D. Neumann GoogleMaps , T. Moritz, M. Mertzen, A.A. Saadelnour Abdalla, M.A. Abdallah, 17 Apr. 2016 ; ZSM 44742 View Materials (4), 75.6-107.9 mm SL, Sudan: White Nile at Kosti, floodplain at southernmost tip of Aba Island (N13.18849° E32.67175°), coll. D. Neumann GoogleMaps , T. Moritz, M. Mertzen, A.A. Saadelnour Abdalla, M.A. Abdallah, 16 Apr. 2016 ; ZSM 44856 View Materials (4), 63.9-83.5 mm SL, same data as ZSM 44722 GoogleMaps ; ZSM 44743 View Materials (8 now 4), 76.2-121.2 mm SL, Sudan: purchased at Omdourman Souq el Samak [fish market], allegedly traded from Jebel Aulia below dam (N15.24° E32.5°), coll. D. Neumann, C. Ratschan, A.A. Saadelnour Abdalla, 13 Apr. 2016 GoogleMaps ; BMNH 2016.8.24.1-2 (2, ex. ZSM 44743 View Materials ), 81.0- 104.2 mm SL ; MRAC 2016.023 View Materials .P.0001-0002 (2, ex. ZSM 44743 View Materials ), 82.8- 112.2 mm SL ; ZSM 44745 View Materials (1), 106.2 mm SL, Sudan: White Nile, sand bank between Kosti and Aba Island (N13.18864° E32.66605°), coll. D. Neumann, A.A. Saadelnour Abdalla, M.A. Abdallah, 19 Apr. 2016 GoogleMaps ; ZSM 44840 View Materials (2), 107.8-108.0 mm SL, Sudan: purchased at Omdourman Souq el Samak [fish market], supposedly traded from the area of Al Jabalayn , coll. D. Neumann, C. Ratschan, A.A. Saadelnour Abdalla, 10. Apr. 2016 ; ZSM 44866 View Materials (6 now 4), 79.6- 96.4 mm SL, Sudan: purchased in Omdourman Souq el Samak [fish market], likely traded from Al Jabalayn (N12.5° E32.8°), coll. D. Neumann, C. Ratschan, A.A. Saadelnour, 13 Apr. 2016 GoogleMaps ; AMNH 266892 About AMNH (2, ex. ZSM 44866 View Materials ), 77.9-88.7 mm SL .
Other material. – DMM IE/10702 (12), 68.9-110.4 mm SL, Sudan: purchased at Omdourman Souq el Samak [fish market], traded from the White Nile, exact locality unclear (likely Jebel Aulia ), coll. T. Moritz, M. Mertzen, D. Neumann, 13 Apr. 2016 ; DMM IE/10728 (3), 84.0- 91.1 mm SL, Sudan: purchased at Omdourman Souq el Samak [fish market], traded from Jebel Aulia , coll. T. Moritz, M. Mertzen, D. Neumann, 13 Apr. 2016 ; DMM IE/10743 (1), 52.7 mm SL, Sudan: White Nile floodplain at southernmost tip of Aba Island (N13.18849° E32.67175°), coll. D. Neumann, T. Moritz, M. Mertzen, A.A. Saadelnour Abdalla, M.A. Abdallah, 16 Apr. 2016 GoogleMaps ; ZSM 44626 View Materials (1), 111.9 mm SL; Sudan: purchased at Omdourman Souq el Samak [fish market], likely traded from Jebel Aulia, coll. D. Neumann, Z.N. El Dayem Mahmoud, 03 Aug. 2015 ; SNHM (unregistered), several specimens, Sudan: White Nile floodplain at southernmost tip of Aba Island (N13.18849° E32.67175°), coll. D. Neumann, T. Moritz, M. Mertzen, A.A. Saadelnour Abdalla, M.A. Abdallah, 16 Apr. 2016 GoogleMaps .
Diagnosis
Labeo latebra differs from all other Labeo species from the Nile in having only 12 (rarely 13) scales around the caudal peduncle (vs. 16 in L. meroensis , 16-18 in L. forkalii and L. coubie , 16-20 in L. horie , and 18-22 in L. niloticus ). It further differs from all other Labeo in the Main Nile (sensu Neumann et al., 2016) except L. meroensis in having only 4.5 (rarely 5 or 5.5) scales between lateral line and mid-dorsal line (vs. 6.5-7.5 in L. forskalii and L. coubie , 6.5-8.5 in L. horie , and 8.5-9.5 in L. niloticus ). From L. meroensis it differs in having 34-37 scales in lateral line (vs. 39-41 in L. meroensis ).
Labeo latebra shares 12 caudal peduncle scales as diagnosed in Reid (1985) with the following African Labeo species: L. parvus Boulenger, 1902 and L. lukulae Boulenger, 1902 from the Congo basin, L. chariensis Pellegrin, 1904 and L. djourae Blache & Miton, 1960 from the Chad basin, L. ogunensis Boulenger, 1910 and L. brachypoma Günther, 1868 from Nilo-Sudanic river basins west of the Niger Delta, and the Upper Guinean endemit L. obscurus Pellegrin, 1908 , which is confined to the Konkouré River. Labeo latebra sp. nov. differs from L. ogunensis by having 3.5 (rarely 4) scales between lateral line and ventral fin insertion (vs. 4.5 in L. ogunensis ). From L. parvus , L. obscurus and L. brachypoma in a higher lateral line scale count of 34-37 (vs. 30-33), and finally from L. djourae , L. lukulae and L. chariensis in the poorly developed snout which lacks a prominent suckermouth (vs. prominently swollen snout with well-developed sucker), the poorly developed ethmoid furrow (vs. very prominent ethmoid furrow) and the small nub-like tubercles on the snout (vs. usually prominent, acanthoid snout tubercles).
Description
Based on holotype ( Figs 2-3 View Figure 2 View Figure 3 ) and 33 paratypes. A smallsized Labeo species belonging to the cylindriform L. forskalii group sensu Reid (1985), which is characterised by its streamlined body, falciform dorsal fin and 9-10 branched dorsal fin rays. Maximum recorded size 126.4 mm SL (163.10 mm TL). Counts and proportional measurements are given in tables I and II. Body cylindriform and rather roundish with only slight lateral compression ( Figs 2 View Figure 2 , 3 View Figure 3 , 7 View Figure 7 ). Eyes medium-sized, in slight dorsolateral position, not visible if specimens are viewed ventrally. Tube of anterior nasal opening poorly developed, snout only feebly swollen, ethmoid furrow absent or only weakly developed ( Fig. 4 View Figure 4 ); tubercles if present small, restricted to dorsal snout and ethmoid furrow area, but absent from interorbial fields; rostral flap minute, closely adhering to upper lip except free distal lobes. Mouth without prominent sucker ( Fig. 5 View Figure 5 ), the two barbels proximal deeply embedded in lip fold but often with visible free distal tips, which reach beyond jaw articulation; inner upper labial fold with crenulated costae.
Dorsal fin concave with two simple and 10 branched rays; two additional small supranumerary simple spines in front of dorsal fin only visible in X-rays ( Fig. 6 View Figure 6 ); branched rays without filamentous extension. In smaller specimens dorsal fin slightly concave, changing to a more falciform contour in larger specimens. Pectoral fins inserted rather low on body flanks, their free ends reach to level of the dorsal fin origin but rarely beyond and terminate well in front of pelvic fin base. Pelvic fin insertion level with pectoral fins and situated below the anterior half of dorsal fin; pelvics reach exactly to the anus. Anus and anal fin insertion separated by three to four scales, anal fin with two simple and five branched rays plus and an additional single small supranumerary simple spine ( Fig. 6 View Figure 6 ). Caudal fin deeply notched, lobes pointed with 10 principal rays on upper and 9 (rarely 10) on lower lobe.
Colouration. – Living specimens with light grey to olivebrownish back with silvery reflections ( Figs 3 View Figure 3 , 7B View Figure 7 ); lateral band faintly visible, including first scale row above and below lateral line; prominent dark blotch with bright green iridescence directly behind operculum at same level of eye and of roughly the same height or smaller. Body colouration below lateral line gradually brightening to light beige or white. Single scales with prominent bright orange centres loosely scattered on body flanks, visibly especially in dead fishes ( Fig. 3 View Figure 3 ). Posterior rim of scales intensely pigmented and dark except for belly-scales and scales near anal fin base; scales on the caudal peduncle with dark margin pronouncing the contour of each scale. Dorsal portion of the head yellowish-brown with greenish hue and similar green iridescence as on opercular series and cheek. Transverse dark stripe connecting tip of snout and eye which exceeds beyond the lower rim of eye ( Fig. 7B, D View Figure 7 ). A second parallel dark band is occasionally visible connecting the nasal openings. On the lower head dark colours of the dorsal part gradually fade to light beige or white. Upper and caudal portions of iris prominent bright orange-red, ventrally blackish. All fins pale and translucent, grey markings near origin of dorsal fin rays, first pectoral and pelvic fin ray with whitish hue. Fins in fresh dead specimens clearly reddish to orange superimposed with a rather dark grey coloration; caudal fin lobes of individual specimens with faint dark margin on upper and lower lobe of caudal fin.
Preserved specimens dorsally brown, ventrally light beige. Lateral band faintly visible, less pronounced as in L. parvus or L. ogunensis . Fins pale whitish, but not translucent, with weak pigmentation between rays of unpaired fins; caudal fin lobes with dark margin, more pronounced on lower lobe. Strong artificial orange-brown staining especially on the skull (e.g. cleithrum, preoperculum) in preserved species, including soft tissues in single specimens as a result of fat staining during initial fixation.
Distribution
Known so far from the White Nile in the Republic of the Sudan, from Jebel Aulia to close to the border of the Republic South Sudan in the vicinity of Makhaleif ( Fig. 1 View Figure 1 ). Early findings in the Khartoum and Omdourman in 2006 and 2008 fish markets, which arrived with Dinka fish traders from the area of Malakal (N9°31’ E31°39’), suggest that the distribution extends further south into the Sudd area GoogleMaps .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.