Petrocephalus zakoni Lavoué, Sullivan & Arnegard, 2010
Behaviour:
As most of the Petrocephalus, P. zakoni is active at night, forming school of several individuals in the Lékoni River system (OdzalaNational Park, Congo basin)
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Mormyridae
Petrocephalus zakoni Lavoué, Sullivan & Arnegard 2010
Petrocephalus zakoni Lavoué, Sullivan & Arnegard, 2010
General description:Petrocephalus zakoni is a small sized species within the genus (maximum standard length = 90 mm). Body ovoid, body 2.5-2.8 longer than high and laterally compressed. Head length between 3.4 and 3.7 times in standard length. Eye large compared to many Petrocephalus species (3.1 ≤ Head length/Eye diameter ≤ 3.3). Snout short and round. Mouth small (4.4 ≤ Head length/Mouth width ≤ 5.0) and sub–terminal, opening under the posterior half of the eye. Teeth small and bicuspid, 6–10 (paratype median = 8, holotype = 9) in a single row in the upper jaw, 18–22 (paratype median = 19, holotype = 20) in the lower jaw. Dorsal and anal fins originate in the posterior half of the body (1.6 ≤ Standard length/predorsal distance ≤ 1.7; 1.6 ≤ Standard length/preanal distance ≤ 1.7). Pre–dorsal distance roughly equal to the pre–anal distance. Dorsal fin with 23–24 branched rays. Anal fin with 27–28 branched rays. Scales cover the body, except for the head. Lateral line visible and complete with 36–38 pored scales along its length. Twelve to 14 scales between the anterior base of the anal fin and the lateral line. Caudal peduncle thin (1.9 ≤ Caudal peduncle length/Caudal peduncle depth ≤ 2.3). Twelve scales around the caudal peduncle.
Skin on head thick, becoming opaque with formalin fixation. Knollenorgans on the head are not clustered into "rosettes" but, instead, appear as isolated receptor pores, the character state observed in the Mormyrinae.
Body uniformly white–silver, with the presence of three characteristic pigmentation marks: (1) a very distinctive black mark just below the anterior base of the dorsal fin on each side, often extending onto the first dorsal rays and making contact over the dorsum with the contralateral mark; (2) a black mark at the base of the pectoral fins; (3) a crescent–shaped black mark centered at the base of the caudal fin on each side, extending onto the upper and lower parts of the caudal fin. Fins otherwise translucent.
Diagnostic description:Petrocephalus zakoni is distinguished from all other Petrocephalus species in Central Africa (Lower Guinea and Congo provinces) by the following combination of characteristics. Dorsal fin with 23–24 branched rays. Anal fin with 27–28 branched rays. Eye large (Head length/Eye diameter ≤ 3.3, range = 3.1–3.3). Mouth small (4.4 ≤ Head length/Mouth Width, range = 4.4–5.0). Ten teeth or fewer (range = 6–10) in the upper jaw. Twenty–two teeth or fewer (range = 18–22) in the lower jaw.
Unique pigmentation pattern consisting of three well defined black patches: (1) an intense dark mark on each side of the body close to the anterior base of the dorsal fin, often extending onto the first dorsal rays, forming a characteristic saddle across the dorsum; (2) a mark on each side of the body at the base of the pectoral fin; (3) a crescent–shaped mark on each side of the body centered at the base of the caudal fin, extending onto the upper and lower parts of the caudal fin. EOD of normal polarity (i.e., first major phase head–positive).
Behaviour:EOD waveforms produced by Petrocephalus zakoni are of relatively short duration among Petrocephalus (range = 0.164 – 0.281 msec), but they are, nevertheless, very similar in waveform to the EODs of several other Petrocephalus species (manily biphasic). EOD sex differences are not apparent in the Odzala population.
Electrocytes are assumed to be of type NPp based on characteristics of the EOD, although electrocyte anatomy has not yet been confirmed histologically.
Size:to 90 mm SL
Evolution:P. zakoni represents a distinct lineage within the genus Petrocephalus, sister group of a large clade composed of mostly Central-Africa endemic species.
Distribution:Apparently endemic to the Congo basin. Abundant in Odzala National Park. We collected P. zakoni at several localities along the main channel of the Lékoli River at night. Elsewhere in the Congo basin, we have identified specimens of P. zakoni from the Lower Congo (Pool Malebo), from the Sangha River basin and as far as the Yangambi region (middle Congo).
EOL Text
Electric Organ Discharge:
EOD waveforms produced by Petrocephalus zakoni are of relatively short duration among Petrocephalus (range = 0.164 – 0.281 msec), but they are, nevertheless, very similar in waveform to the EODs of several other Petrocephalus species (manily biphasic). EOD sex differences are not apparent in the Odzala population.
Electrocytes are assumed to be of type NPp based on characteristics of the EOD, although electrocyte anatomy has not yet been confirmed histologically.
| License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
| Rights holder/Author | Lavoué, Sébastien, Lavoué, Sébastien, Africhthy |
| Source | http://mormyrids.lifedesks.org/pages/2593 |
Behavior:
As most of the Petrocephalus, P. zakoni is active at night, forming school of several individuals in the Lékoni River system (OdzalaNational Park, Congo basin)
| License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
| Rights holder/Author | Lavoué, Sébastien, Lavoué, Sébastien, Africhthy |
| Source | http://mormyrids.lifedesks.org/pages/2593 |
Phylogenetic Relationships:
P. zakoni represents a distinct lineage within the genus Petrocephalus, sister group of a large clade composed of mostly Central-Africa endemic species.
| License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
| Rights holder/Author | Lavoué, Sébastien, Lavoué, Sébastien, Africhthy |
| Source | http://mormyrids.lifedesks.org/pages/2593 |
Statistics of barcoding coverage: Petrocephalus zakoni:
Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 3
Species With Barcodes: 1
Not Evaluated
| License | http://creativecommons.org/licenses/by-nc/3.0/ |
| Rights holder/Author | Armi G. Torres, FishBase |
| Source | http://www.fishbase.org/summary/SpeciesSummary.php?id=66163 |
Petrocephalus zakoni ZBK , new species
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- Lavoué, Sébastien, Sullivan, John P., Arnegard, M. E. (2010): African weakly electric fishes of the genus Petrocephalus (Osteoglossomorpha: Mormyridae) of Odzala National Park, Republic of the Congo (Lékoli River, Congo River basin) with description of five new species. Zootaxa 2600, 1-52: 9-9
| License | Public Domain |
| Rights holder/Author | 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. |
| Source | http://treatment.plazi.org/id/C10ACFB25FE17DD7E5374C0722586A64 |
Importance:
fisheries:
| License | http://creativecommons.org/licenses/by-nc/3.0/ |
| Rights holder/Author | Armi G. Torres, FishBase |
| Source | http://www.fishbase.org/summary/SpeciesSummary.php?id=66163 |
General Description:
Petrocephalus zakoni is a small sized species within the genus (maximum standard length = 90 mm). Body ovoid, body 2.5-2.8 longer than high and laterally compressed. Head length between 3.4 and 3.7 times in standard length. Eye large compared to many Petrocephalus species (3.1 ≤ Head length/Eye diameter ≤ 3.3). Snout short and round. Mouth small (4.4 ≤ Head length/Mouth width ≤ 5.0) and sub–terminal, opening under the posterior half of the eye. Teeth small and bicuspid, 6–10 (paratype median = 8, holotype = 9) in a single row in the upper jaw, 18–22 (paratype median = 19, holotype = 20) in the lower jaw. Dorsal and anal fins originate in the posterior half of the body (1.6 ≤ Standard length/predorsal distance ≤ 1.7; 1.6 ≤ Standard length/preanal distance ≤ 1.7). Pre–dorsal distance roughly equal to the pre–anal distance. Dorsal fin with 23–24 branched rays. Anal fin with 27–28 branched rays. Scales cover the body, except for the head. Lateral line visible and complete with 36–38 pored scales along its length. Twelve to 14 scales between the anterior base of the anal fin and the lateral line. Caudal peduncle thin (1.9 ≤ Caudal peduncle length/Caudal peduncle depth ≤ 2.3). Twelve scales around the caudal peduncle.
Skin on head thick, becoming opaque with formalin fixation. Knollenorgans on the head are not clustered into "rosettes" but, instead, appear as isolated receptor pores, the character state observed in the Mormyrinae.
Body uniformly white–silver, with the presence of three characteristic pigmentation marks: (1) a very distinctive black mark just below the anterior base of the dorsal fin on each side, often extending onto the first dorsal rays and making contact over the dorsum with the contralateral mark; (2) a black mark at the base of the pectoral fins; (3) a crescent–shaped black mark centered at the base of the caudal fin on each side, extending onto the upper and lower parts of the caudal fin. Fins otherwise translucent.
| License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
| Rights holder/Author | Lavoué, Sébastien, Lavoué, Sébastien, Africhthy |
| Source | http://mormyrids.lifedesks.org/pages/2593 |
Africa: Congo River basin (Ref. 85331).
| License | http://creativecommons.org/licenses/by-nc/3.0/ |
| Rights holder/Author | Armi G. Torres, FishBase |
| Source | http://www.fishbase.org/summary/SpeciesSummary.php?id=66163 |
Distribution:
Apparently endemic to the Congo basin. Abundant in Odzala National Park. We collected P. zakoni at several localities along the main channel of the Lékoli River at night. Elsewhere in the Congo basin, we have identified specimens of P. zakoni from the Lower Congo (Pool Malebo), from the Sangha River basin and as far as the Yangambi region (middle Congo).
| License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
| Rights holder/Author | Lavoué, Sébastien, Lavoué, Sébastien, Africhthy |
| Source | http://mormyrids.lifedesks.org/pages/2593 |