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Measuring Behavior 2018 Conference Proceedings
Full text linkThese proceedings contain the papers presented at Measuring Behavior 2018, the 11th International Conference on Methods and Techniques in Behavioral Research. The conference was organised by Manchester Metropolitan University, in collaboration with Noldus Information Technology. The conference was held during June 5th – 8th, 2018 in Manchester, UK. Building on the format that has emerged from previous meetings, we hosted a fascinating program about a wide variety of methodological aspects of the behavioral sciences. We had scientific presentations scheduled into seven general oral sessions and fifteen symposia, which covered a topical spread from rodent to human behavior. We had fourteen demonstrations, in which academics and companies demonstrated their latest prototypes. The scientific program also contained three workshops, one tutorial and a number of scientific discussion sessions. We also had scientific tours of our facilities at Manchester Metropolitan Univeristy, and the nearby British Cycling Velodrome. We hope this proceedings caters for many of your interests and we look forward to seeing and hearing more of your contributions
Petrocephalus odzalaensis Lavoué, Sullivan & Arnegard, 2010, n. sp.
No full textPetrocephalus odzalaensis n. sp. [Odzala field identification and in Lavoué et al. (2008): Petrocephalus sp. 6, OTU 6] Images. Fig. 8 A, photo of a live specimen from Odzala and Fig. 8 B, photo of the preserved holotype (CU 88048). Type material. Holotype, CU 88048 (morpho, EOD), sex undet., 92.9 mm SL. Republic of the Congo, Lékénie River at Mboko débarcadère (Congo basin), Odzala National Park, (0.62 ° N, 14.90 ° E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., August 2002. Paratypes. CU 87850 (morpho, EOD), male, 90.1 mm SL; CU 87857 (morpho, EOD), male, 92.6 mm SL; CU 88050 (morpho, EOD), male, 90.4 mm SL; AMNH 251414 (ex CU 87843) (morpho, EOD), male, 87.0 mm SL; AMNH 251417 (ex CU 88056) (morpho, EOD), male, 87.6 mm SL; AMNH 251416 (ex CU 88054) (morpho, EOD), male, 97.6 mm SL; CU 88059 (morpho, EOD), male, 99.3 mm SL; AMNH 251415 (ex CU 87844) (morpho, EOD), male, 87.3 mm SL. Republic of the Congo, Lékénie River at Mboko débarcadère (Congo basin), Odzala National Park, (0.62 ° N, 14.90 ° E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., August 2002. CU 88049 (morpho, EOD; caudal peduncle dissected by Lavoué et al. (2008) to sample electric organ for histological examination), male, 93.2 mm SL. Republic of the Congo, Lékénie River at Mboko débarcadère (Congo basin), Odzala National Park, (0.62 ° N, 14.90 ° E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., 12 August 2002. Holotype (o) Paratypes (n= 9) Min–Max Mean Std–Dev Min–Max Median Meristic counts: Dorsal fin branched rays (DR) 22 20–22 21 Anal fin branched rays (AR) 29 27–29 28 Number of scales in the lateral line (SLL) 38 36–38 37 Number of scale rows between the anterior base of 11 10–14 12 the anal fin and the lateral line (SDL) Number of teeth in the upper jaw (TUJ) 11 8–12 11 Number of teeth in the lower jaw (TLJ) 18 18–23 20 Other specimens. We examined 19 other specimens from Odzala National Park (specimen list provided in the section "additional material examined"). Diagnosis. Petrocephalus odzalaensis n. sp. is distinguished from all other Petrocephalus species in Central Africa by the following combination of characteristics. Dorsal fin shorter than anal fin. Dorsal fin with a maximum of 22 branched rays (range = 20–22). Anal fin with a minimum of 27 branched rays (range = 27–29). Mouth sub-terminal; ratio between head length and mouth position is between 4.2 and 5.0. Eye small (3.7 ≤ HL/ED ≤ 4.2). Body pinkish-gray, darker dorsally, with the presence of three distinct pigmentation patches: (1) a distinct ovoid black mark situated below the anterior base of the dorsal fin on each side of the body; (2) a small black mark at the base of each pectoral fin; (3) an ovoid black mark on each side that is centered at the base of the caudal fin, not extending onto the upper and lower lobes of this fin. EOD of normal polarity, appearing triphasic at low gain, with two main phases and a small third phase. A final, fourth phase may be present, but it is always extremely small (<1.5 % of total peak-to-peak amplitude). Description. Morphometric ratios and meristic data for the holotype and paratypes are presented in Table 6. Petrocephalus odzalaensis n. sp. is a medium sized species within the genus (maximum SL observed = 99.3 mm; holotype = 92.9 mm). Body ovoid, longer than high (2.6 ≤ SL /H ≤ 2.9, paratype average = 2.8, holotype = 2.6) and laterally compressed. Head length between 3.7 and 4.0 times in standard length (paratype average = 3.9, holotype = 4.0). Snout short (6.2 ≤ HL/SNL ≤ 8.3, paratype average = 7.3, holotype = 6.6) and round. Mouth small (4.0 ≤ HL/MW ≤ 4.8, paratype average = 4.3, holotype = 4.3), sub-terminal, opening just under the anterior half of the eye. Teeth small and bicuspid, 8–12 in a single row in the upper jaw (paratype median = 11, holotype = 11), 18–23 in a single row in the lower jaw (paratype median = 20, holotype = 18). Dorsal and anal fins originate in the posterior half of the body (1.5 ≤ SL / PDD ≤ 1.6 and 1.6 ≤ SL /PAD ≤ 1.7, respectively). Pre-dorsal distance slightly greater than the pre–anal distance (1.0 ≤ PDD /PAD ≤ 1.1). Dorsal fin with 20–22 branched rays (paratype median = 21, holotype = 22). Anal fin with 27–29 branched rays (paratype median = 28, holotype = 29). Scales cover the body, except for the head. Lateral line visible and complete with 36–38 (holotype = 38) pored scales along its length. Ten to 14 scales (paratype average = 12, holotype = 11) between the anterior base of the anal fin and the lateral line. Caudal peduncle thin (1.9 ≤ CPL/ CPD ≤ 2.3, paratype average = 2.1, holotype = 2.1). Twelve scales around the caudal peduncle. Skin on head thick, turning opaque with formalin fixation. Knollenorgans clustered into the three distinct "rosettes" of Harder (1968). Live coloration (Fig. 8 A). Body background color pinkish-gray, darker dorsally. Pigmentation pattern consisting of three characteristic black patches: (1) a distinct ovoid black mark below the anterior base of the dorsal fin; (2) a small black mark at the base of the pectoral fin; and (3) an ovoid black mark centered at the base of the caudal fin, which does not extend onto the upper and lower lobes. Fins translucent. Distribution (Fig. 1). Endemic to the Congo basin. Abundant in Odzala. We collected P. odzalaensis n. sp. at several localities along the main course of the Lékoli River and in some small tributary creeks flowing through forest. Electric organ discharge (Fig. 8 C). The EOD waveform is typical for the genus, similar to EODs produced by many other Petrocephalus species. Total EOD duration ranges from 0.231 to 0.339 msec, based on 1.5 % voltage deviations from baseline relative to peak-peak amplitude. No EOD sex differences are apparent in the specimens recorded thus far. Lavoué et al. (2008) provide additional statistics for waveform landmarks and other EOD measurements. Histological examination confirms that electrocytes are type NPp (Lavoué et al., 2008). Remarks. Based on museum records from the Congo basin (pers. obs.), Petrocephalus odzalaensis has been misidentified as Petrocephalus simus in several instances. The latter species is endemic to the Lower Guinea province (Lavoué et al., 2004). Etymology. Named for Odzala National Park.Published as part of Lavoué, Sébastien, Sullivan, John P. & Arnegard, Matthew 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, pp. 1-52 in Zootaxa 2600 on pages 22-25, DOI: 10.5281/zenodo.19758
Petrocephalus zakoni Lavoué, Sullivan & Arnegard, 2010, n. sp.
No full textPetrocephalus zakoni n. sp. [Odzala field identification and in Lavoué et al. (2008): Petrocephalus sp. 2, OTU 2] Images. Fig. 4 A, photo of a live specimen from Odzala and Fig. 4 B, photo of the preserved holotype (CU 88101). Type material. Holotype, CU 88101 (morpho, EOD), male, 86.0 mm SL. Republic of the Congo, small channel around island in Lékoli River (Congo basin), Odzala National Park, (0.62 ° N, 14.95 ° E). J.P. Friel, S. Lavoué & J.P. Sullivan coll., 20 August 2002. Paratypes. CU 88036 (morpho, EOD), sex undet., 81.4 mm SL; CU 88042 (morpho, EOD), male, 78.6 mm SL; CU 88037 (morpho, EOD), sex undet., 79.6 mm SL; CU 88077 (morpho), male, 84.8 mm SL. Republic of the Congo, Pandaka River (Congo basin), Odzala National Park, (0.62 ° N, 14.92 ° E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., August 2002. CU 88104 (morpho, EOD), sex undet., 83.5 mm SL; AMNH 251426 (ex CU 88100) (morpho, EOD), male, 73.7 mm SL; AMNH 251427 (ex CU 88103) (morpho, EOD), sex undet., 77.2 mm SL. Republic of the Congo, small channel around island in Lékoli River (Congo basin), Odzala National Park (0.62 ° N, 14.95 ° E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., August 2002. CU 88093 (morpho, EOD), male, 67.4 mm SL; AMNH 251424 (ex CU 88088) (morpho, EOD), sex undet., 75.8 mm SL; AMNH 251425 (ex CU 88090) (morpho, EOD), male, 76.0 mm SL. Republic of the Congo, small channel around island in Lékoli River (Congo basin), Odzala National Park (0.62 ° N, 14.92 ° E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., August 2002. Other specimens. We examined 34 other specimens from Odzala National Park (specimen list provided in the section "additional material examined"). Diagnosis. Petrocephalus zakoni n. sp. 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 or 24 branched rays. Anal fin with 27 or 28 branched rays. Eye large (HL/ED ≤ 3.3, range = 3.1–3.3). Mouth small (4.4 ≤ HL/MW, range = 4.4 –5.0). Ten teeth or fewer (range = 6–10) in the upper jaw. Twentytwo teeth or fewer (range = 18–22) in the lower jaw. Unique pigmentation pattern consisting of three well defined black patches (Fig. 4 A): (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). Description. Morphometric ratios and meristic data are given in Table 2 for the holotype and paratypes separately. Petrocephalus zakoni n. sp. is a small sized species within the genus (maximum SL in the type series = 86.0 mm, maximum SL observed in all specimens = 90 mm). Body ovoid, longer than high (2.5 ≤ SL / H ≤ 2.8, paratype average = 2.6, holotype = 2.8) and laterally compressed. Head length between 3.4 and 3.7 times in standard length (paratype average = 3.6, holotype = 3.6). Eye large compared to many Petrocephalus species (3.1 ≤ HL/ED ≤ 3.3, paratype average = 3.2, holotype = 3.2). Snout short (6.1 ≤ HL/SNL ≤ 8.5, paratype average = 7.2, holotype = 6.2) and round. Mouth small (4.4 ≤ HL/MW ≤ 5.0, paratype average = 4.7, holotype = 4.5) 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 ≤ SL / PDD ≤ 1.7, paratype average and holotype = 1.6; 1.6 ≤ SL /PAD ≤ 1.7, paratype average and holotype = 1.6). Pre-dorsal distance roughly equal to the pre-anal distance. Dorsal fin with 23 or 24 branched rays (median = 23, holotype = 24). Anal fin with 27 or 28 branched rays (median = 27, holotype = 28). Scales cover the body, except for the head. Lateral line visible and complete with 36–38 pored scales along its length (paratype average = 37, holotype = 38). Twelve to 14 scales (paratype average = 13, holotype = 14) between the anterior base of the anal fin and the lateral line. Caudal peduncle thin (1.9 ≤ CPL/CPD ≤ 2.3, paratype average = 2.1, holotype = 2.2). 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. Live coloration (Fig. 4 A). 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 blackish mark, sometimes weak but always visible, at the base of the pectoral fins; (3) a crescentshaped 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. Distribution (Fig. 1). Apparently endemic to the Congo basin. Abundant in Odzala. We collected P. zakoni n. sp. at several localities along the main channel of the Lékoli River at night. Elsewhere in the Congo basin, we have identified specimens of P. z a k o n i n. sp. from the Lower Congo (Pool Malebo) and from the Sangha River basin (unpublished observations). Electric organ discharge (Fig. 4 C). EOD waveforms produced by P. zakoni n. sp. 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. EOD sex differences are not apparent in the Odzala population. Statistics for waveform landmarks and other EOD measurements are provided by Lavoué et al. (2008). Electrocytes are assumed to be of type NPp based on characteristics of the EOD, although electrocyte anatomy has not yet been confirmed histologically. Remarks. Given our identification of specimens from the Lower Congo River and the Dzangha-Sangha Reserve (Sangha River), Petrocephalus zakoni n. sp. is likely a common species in the Congo basin. This species has been previously misidentified as Petrocephalus christyi Boulenger, 1920 because its body proportions are similar to those of P. christyi. In addition, both species exhibit an intense sub-dorsal melanin marking on the flank. Nevertheless, these species can be distinguished by the presence of a black spot at the base of the pectoral fins in P. zakoni n. sp. (absent in P. christyi), the shape of the sub-dorsal marking (ovoid to saddle-shaped versus rounded in P. christyi), the waveshape of the EOD (with two main phases and a weak third phase in P. zakoni versus four phases in P. christyi) and presence/absence of Knollenorgan rosettes on the head (absent in P. zakoni versus present in P. christyi). Holotype (m) Paratypes (n= 10) Min–Max Mean Std–Dev Min–Max Median Meristic counts: Number of scale rows between the anterior base of 14 12–14 13 the anal fin and the lateral line (SDL) Number of teeth in the upper jaw (TUJ) 9 6–10 8 Number of teeth in the lower jaw (TLJ) 20 18–22 19 Etymology. Named in honor of Harold H. Zakon. In addition to Professor Zakon’s many contributions to neuroethology, we recognize the significance of his recent work (Zakon et al., 2006), which inspires a new area of research on genes that underlie electrolocation and electrical communication in gymnotiform and mormyroid fishes.Published as part of Lavoué, Sébastien, Sullivan, John P. & Arnegard, Matthew 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, pp. 1-52 in Zootaxa 2600 on pages 9-12, DOI: 10.5281/zenodo.19758
Petrocephalus pulsivertens Lavoué, Sullivan & Arnegard, 2010, n. sp.
No full textPetrocephalus pulsivertens n. sp. [Odzala field identification and in Lavoué et al (2008): Petrocephalus sp. 9, OTU 9] Images. Fig. 11 A, photo of a live specimen from Odzala and Fig. 11 B, photo of the preserved holotype (CU 88085). Type material. Holotype, CU 88085 (morpho, DNA), male, 114.8 mm SL. Republic of the Congo, small channel around island in Lékoli River (Congo basin), Odzala National Park, (0.62 ° N, 14.95 ° E), V. Mbossi, J.P. Friel, S. Lavoué & J.P. Sullivan coll., 16 August 2002. Paratypes. AMNH 251418 (ex CU 88096) (morpho, EOD), male, 99.9 mm SL; CU 88097 (morpho, EOD, DNA; caudal peduncle dissected by Lavoué et al. (2008) to sample electric organ for histological examination), sex undet., 95.0 mm SL; AMNH 251419 (ex CU 88098) (morpho, EOD), sex undet., 103.2 mm SL. Republic of the Congo, small channel around island in Lékoli River (Congo basin), Odzala National Park, (0.62 ° N, 14.95 ° E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., 20 August, 2002. CU 87839 (morpho, EOD, DNA), male, 87.3 mm SL; CU 89188 (morpho), sex undet., 98.5 mm SL; CU 89188 (morpho, caudal peduncle dissected by Lavoué et al. (2008) to sample electric organ for histological examination, sex undet., 103.6 mm SL; CU 89188 (morpho), male, 107.4 mm SL; CU 89188 (morpho), male, 86.1 mm SL. Republic of the Congo, small channel around island in Lékoli River (Congo basin), Odzala National Park, (0.62 ° N, 14.95 ° E), V. Mbossi, J.P. Friel, S. Lavoué & J.P. Sullivan coll., 16 August 2002. Other specimens. We examined five other specimens from Odzala National Park and one from the Sangha River basin (specimen list provided in the section "additional material examined"). Diagnosis. Petrocephalus pulsivertens n. sp. is distinguished from all other Petrocephalus species in Central Africa by the following combination of characteristics. Dorsal fin with at least 25 branched rays (range = 25–27). Anal fin with at least 31 branched rays (range = 31–35). Mouth large (HL/MW ≤ 3.7, range = 3.0– 3.7). Fifteen to 21 teeth in the lower jaw; 24–30 teeth in the upper jaw. Eye large (HL/ED ≤ 3.5, range = 3.2–3.5). Pigmentation pattern consists of two distinctive melanin markings (black patches): (1) a distinct ovoid mark below the anterior base of the dorsal fin; and (2) a crescent-like mark, sometimes diffuse, centered at the base of the caudal fin and extending onto the upper and lower parts of the caudal fin. EOD appears to be inverted in polarity, with a first main phase that is negative under the standard recording geometry, resulting in a waveform that is very distinctive in comparison to all known congeners. Description. Morphometric ratios and meristic data for the holotype and paratypes are presented in Table 9. Petrocephalus pulsivertens n. sp. is a relatively large sized species within the genus Petrocephalus (maximum SL observed = 114.8 mm, the length of the holotype). Body ovoid, longer than high (2.6 ≤ SL /H ≤ 2.9, paratype average = 2.7, holotype = 2.8) and laterally compressed. Head length between 3.6 and 3.7 times in standard length (holotype = 3.7). Eye large (3.2 ≤ HL/ED ≤ 3.5, paratype average = 3.4, holotype = 3.5). Snout short (6.1 ≤ HL/SNL ≤ 7.3, paratype average = 6.5, holotype = 6.8) and round. Mouth large (3.0 ≤ HL/ MW ≤ 3.7, paratype average = 3.3, holotype = 3.0), sub-terminal, opening just under the anterior half of the eye. Teeth bicuspid, small and numerous, 15–21 (paratype average = 18, holotype = 21) in a single row in the upper jaw, 24–30 (paratype average = 28, holotype = 29) in a single row in the lower jaw. Dorsal and anal fins originate in the posterior half of the body (1.6 ≤ SL / PDD ≤ 1.7 and 1.7 ≤ SL /PAD ≤ 1.8, respectively). Predorsal distance equal to, or slightly greater than, pre-anal distance (1.0 ≤ PDD /PAD ≤ 1.1). Dorsal fin with 25– 27 branched rays (paratype median = 26, holotype = 26). Anal fin with 31–35 branched rays (paratype median = 33, holotype = 34). Scales cover the body, except for the head. Lateral line visible and complete with 38–40 pored scales along its length. Caudal peduncle relatively thin (2.1 ≤ CPL/CPD ≤ 2.3, holotype = 2.2). Twelve scales around the caudal peduncle. Skin on head thick, becoming opaque with formalin fixation. Knollenorgan electroreceptors on head clustered into three distinct rosettes. Holotype (m) Paratypes (n= 8) Min–Max Mean Std–Dev Min–Max Median Meristic counts: Number of scale rows between the anterior base of 14 13–15 14 the anal fin and the lateral line (SDL) Number of teeth in the upper jaw (TUJ) 21 15–21 18 Number of teeth in the lower jaw (TLJ) 29 24–30 28 Live coloration (Fig. 11 A). Body and head mostly whitish-silvery, but head also exhibits faint metallic blue-purple iridescence. Dorsum darker than the rest of the body. Melanin patterning consists of two distinct black marks: (1) a distinct ovoid melanin mark below the anterior base of the dorsal fin on each side of the body and (2) a crescent-like melanin mark, sometimes diffuse, centered at the base of the caudal fin on each side and extending onto the upper and lower parts of the caudal fin. No black mark is present at the base of the pectoral fins. The fins themselves are mostly translucent, with the dorsal and caudal fins sometimes turning slightly yellow after formaldehyde preservation. Distribution (Fig. 1). Endemic to the Congo River basin. We collected P. pulsivertens n. sp. along the main course of the Lékoli River. This species seemed to be absent from the small tributary creeks flowing through forest or savannah when we surveyed Odzala National Park. Elsewhere, P. pulsivertens n. sp. occurs in the vicinities of Brazzaville (i.e., the Pool Malebo), the Dja River (Cameroon) and the Dzangha-Sangha region (Sangha River basin, Central African Republic) (pers. obs.), although no EOD recordings have been made of this species outside Odzala. Electric organ discharge (Fig. 11 C). The EOD waveform of P. pulsivertens n. sp., which is known only from our recordings in Odzala, resembles an inverted-polarity version of the "typical" Petrocephalus EOD. That is, the temporal sequence of electrocyte face firing known for all other Petrocephalus (i.e., firing of the posterior electrocyte face preceding firing of the anterior electrocyte face) appears to be reversed in P. pulsivertens. At high gain, however, one can see that the very first event in the EOD is a minute head-positive deflection (for an example see Fig. 3 D of Lavoué et al., 2008). This waveform feature is consistent with current from the stalks of the posterior electrocyte face (and possibly early current during the beginning of posterior face firing itself) slightly preceding anterior face firing. Despite the waveform inversion, histological examination of electrocytes of P. pulsivertens n. sp. reveals them to be type "NPp," the character state also shared by all other Petrocephalus species investigated to date. We suspect that part of the mechanism underlying the reversed ordering of major peaks in the EOD of P. pulsivertens n. sp. might involve changes in firing threshold for one or both electrocyte faces (as proposed in Lavoué et al., 2008). This interesting example of waveform inversion in Petrocephalus reminds us that careful attention must be paid to the geometry of electrodes during EOD recordings from unknown mormyrid faunas. Given its inverted-polarity appearance, the EOD of P. pulsivertens n. sp. is immediately recognizable as distinct from those of all other congeners. Based on a threshold of 1.5 % of peak-peak amplitude (and at ambient recording temperatures), the duration of the EOD of P. pulsivertens n. sp. ranges from 0.270 to 0.418 msec, falling in the range of many "typical" Petrocephalus EODs. Statistics for waveform landmarks and other EOD measurements are provided by Lavoué et al. (2008). Etymology. From the Latin " pulsus," impulse, beating; and from " vertere, " to turn, exchange. The name describes the unusual EOD waveform of P. pulsivertens n. sp. The inverted appearance of this species’ EOD is unique among all Petrocephalus recorded to date.Published as part of Lavoué, Sébastien, Sullivan, John P. & Arnegard, Matthew 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, pp. 1-52 in Zootaxa 2600 on pages 32-35, DOI: 10.5281/zenodo.19758
Petrocephalus valentini Lavoué, Sullivan & Arnegard, 2010, n. sp.
No full text<i>Petrocephalus valentini</i> n. sp. <p> [Odzala field identification and in Lavoué <i>et al.</i> (2008): <i>Petrocephalus</i> sp. 3, OTU 3]</p> <p> <b>Images.</b> Fig. 5 A, photo of a live specimen from Odzala and Fig. 5 B, photo of the preserved holotype (CU 88117).</p> <p> <b>Type material.</b> Holotype, CU 88117 (morpho, EOD), male, 77.2 mm SL. Republic of the Congo, Cuvette-Ouest, Lékoli River (Congo basin), Odzala National Park (0.62 <i>°</i> N, 14.93 <i>°</i> E), J.P. Friel, S. Lavoué & J.P. Sullivan, 24 August 2002.</p> <p> Paratypes. CU 87828 (morpho, EOD), sex undet., 73.6 mm SL; AMNH 251420 (ex CU 87827) (morpho, EOD), male, 70.9 mm SL; AMNH 251423 (ex CU 88116) (morpho, EOD), sex undet., 64.5 mm SL; CU 88120 (morpho, EOD), sex undet., 66.7 mm SL; CU 88118 (morpho, EOD, DNA), sex undet., 58.1 mm SL. Republic of the Congo, Cuvette-Ouest, Lékoli River (Congo basin), Odzala National Park (0.62 <i>°</i> N, 14.93 <i>°</i> E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., 24 August 2002. CU 87834 (morpho, EOD), male, 70.6 mm SL; AMNH 251422 (ex CU 88073) (morpho, EOD), sex undet., 65.9 mm SL; AMNH 251421 (ex CU 88072) (morpho, EOD), male, 72.9 mm SL. Republic of the Congo, Cuvette-Ouest, Lékénie River at Mboko débarcadère, Odzala National Park (0.62 <i>°</i> N, 14.91 <i>°</i> E), J.P. Friel, S. Lavoué & J.P. Sullivan coll., August 2002.</p> <p> <b>Other specimens.</b> We examined three other specimens from Odzala National Park (specimen list provided in the section "additional material examined").</p> <p> <b>Diagnosis.</b> <i>Petrocephalus valentini</i> <b>n. sp.</b> is distinguished from all other <i>Petrocephalus</i> species in Central Africa (i.e., Lower Guinea and Congo provinces) by the following combination of characteristics. Dorsal fin with 19–24 branched rays. Anal fin with 24–26 branched rays. Eye large (HL/ED ≤ 3.2, range = 2.9–3.2). Mouth very small (HL/MW ≤ 5.8, range = 4.7–5.8). Twelve teeth or fewer in the upper jaw (range = 7–12), 17 teeth or fewer in the lower jaw (range = 15–17). Pigmentation pattern subtle, including two components: (1) a pale dorsal black mark on each side of the body below the anterior base of the dorsal fin (under the second to sixth dorsal rays); (2) an ovoid mark, sometimes scarcely visible, at the base of the caudal fin, extending weakly onto the upper and lower lobes of the fin. EOD of normal polarity.</p> <p> <b>Description.</b> Morphometric ratios and meristic data are given in Table 3 for the holotype and paratypes separately. <i>Petrocephalus valentini</i> <b>n. sp.</b> is a small sized species within the genus (maximum SL = 77.2 mm, holotype). Body ovoid, longer than high (2.8 ≤ SL/H ≤ 3.0, paratype average = 2.9, holotype = 2.8) and laterally compressed. Head length between 3.4 and 3.7 times in standard length (paratype average = 3.6, holotype = 3.4). Snout short (6.5 ≤ HL/SNL ≤ 8.2, paratype average = 7.4, holotype = 6.5) and round. Mouth small (4.7 ≤ HL/MW ≤ 5.8, paratype average = 5.2, holotype = 5.1) and sub-terminal, positioned under the anterior half of the eye. Eye large (2.9 ≤ HL/ED ≤ 3.2, paratype average = 3.0, holotype = 3.1). Teeth small and bicuspid, 7–12 (paratype median = 9, holotype = 9) in a single row in the upper jaw, 15–17 (paratype median = 16, holotype = 17) in the lower jaw. Dorsal and anal fins originate in the posterior half of the body (1.6 ≤ SL/PDD ≤ 1.7 and SL/PAD = 1.6). Pre-dorsal distance approximately equal to the pre-anal distance. Dorsal fin with 19–24 branched rays (paratype median = 22, holotype = 22). Anal fin with 24–26 branched rays (paratype median = 25, holotype = 25). Scales cover the body, except for the head. Lateral line visible and complete with 35–36 pored scales along its length (paratype median = 36, holotype = 35). Nine to 12 scales (paratype median = 11, holotype = 11) between the anterior base of the anal fin and the lateral line. Caudal peduncle relatively thin (2.2 ≤ CPL/CPD ≤ 2.5, paratype average = 2.3, holotype = 2.3). Twelve scales around the caudal peduncle. Skin on head thick, turning opaque with formalin fixation. Knollenorgans clearly organized into two visible rosettes (the Augenrosette and the Nackenrosette). During our examination of specimens, we were uncertain about the definitive presence of the third rosette, the Kehlrosette, as this structure did not appear to us to be as distinct as it is in some other species (e.g., <i>P. binotatus</i>). Recently, however, more definitive analysis using toluidine blue staining of the skin suggests that the Kehlrosette is in fact present, but it is indeed smaller and harder to discern than in other <i>Petrocephalus</i> (M. Hollmann and B. A. Carlson, <i>unpub. obs.</i>).</p> <p>Holotype (m) Paratypes (n=8)</p> <p>Min–Max Mean Std–Dev Min–Max Median</p> <p>Meristic counts:</p> <p>Number of scale rows between the anterior base of the 11 9–12 11 anal fin and the lateral line (SDL)</p> <p> Number of teeth in the upper jaw (TUJ) 9 7–12 9 Number of teeth in the lower jaw (TLJ) 17 15–17 16 <b>Live coloration</b> (Fig. 5 A). Body uniformly white-silver, with two faint black patches, sometimes hardly distinguishable: (1) a dorsal mark on each side of the body, below the anterior base of the dorsal fin under the second to the sixth rays; (2) an ovoid/crescent-shaped mark centered at the base of the caudal fin (sometimes the center of this second mark is less distinguishable than the two arms of the crescent), with each arm slightly extending onto the upper and lower parts of the caudal fin. There is no melanin marking at the base of the pectoral fins. Fins translucent.</p> <p> <b>Distribution</b> (Fig. 1). Apparently endemic to the Congo basin. Common in Odzala National Park. At night, we collected single specimens cruising in the main channel of the Lékoli River. At the times we surveyed Odzala, <i>P. valentini</i> seemed absent from the small tributary creeks flowing through the park’s forest or savannah. Elsewhere in the Congo basin, <i>P. valentini</i> <b>n. sp.</b> has been collected from the Lower Congo River in the vicinity of the Pool Malebo (museum specimen records, <i>pers. obs.</i>).</p> <p> <b>Electric organ discharge</b> (Fig. 5 C). The EOD waveform produced by <i>P. valentini</i> <b>n. sp.</b> is similar in its characteristics to those produced by many other <i>Petrocephalus</i> species. EOD duration = 0.520 – 1.022 msec.</p> <p> Statistics for waveform landmarks and other EOD measurements are provided by Lavoué <i>et al.</i> (2008). Electrocytes are assumed to be of type NPp based on the EOD waveform, although this has not been confirmed histologically.</p> <p> <b>Remarks.</b> Without careful inspection, it is possible that specimens of <i>Petrocephalus valentini</i> <b>n. sp.</b> could be misidentified as <i>Petrocephalus catostoma</i> or <i>Petrocephalus simus</i> because of the absence or near absence of pigmentation patterns in all three species. However, these three species differ from each other in several morphometric measurements and meristic counts, and their geographical distributions, as currently known, are non-overlapping.</p> <p> <b>Etymology.</b> Named in honor of Mr. Valentin Mbossi, <i>pinassier extraordinaire</i> at Odzala National Park. Fieldwork is as important as laboratory bench work and analysis when it comes to investigations of electric fish taxonomy, behavior and evolution. Valentin assisted us during both of our expeditions to Odzala. We use his first name for this species to reflect our appreciation of him as both colleague and friend and to avoid confusion with a similarly named species, below.</p>Published as part of <i>Lavoué, Sébastien, Sullivan, John P. & Arnegard, Matthew 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, pp. 1-52 in Zootaxa 2600</i> on pages 13-16, DOI: <a href="http://zenodo.org/record/197589">10.5281/zenodo.197589</a>
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