Paramormyrops undetermined, SP.
Creators: name: Rich, Madeline
name: Sullivan, John P.
name: Hopkins, Carl D.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Osteoglossiformes
Mormyridae
Paramormyrops
Paramormyrops undetermined

description: PARAMORMYROPS NTOTOM SP. NOV.
(FIG. 12, TABLE 2)
urn:lsid:zoobank.org:act: 7BD331A4-1E58-4420-91D9- DA197125340B
Holotype: CUMV 98138, 175 mm SL, male, tag number JPS-1189, Gabon, Ogooué-Lolo, Ogooué River at Doumé, GPS coordinates: 0.84137°S, 12.96548°E, J.P. Sullivan & B. Sidlauskas, 17 September 2014.
Paratypes (22): Ogooué River at Doumé (10) (0.843°S, 12.96°E): J.P. Sullivan, 29 May 2011: CUMV 96811, JPS- 1117, 120 mm SL; AMNH 264795, formerly CUMV 96811, JPS- 1119, 110 mm SL; MNHN 2016-0016, formerly CUMV 96811, JPS- 1120, 152 mm SL; MRAC 2016- 010 -P-00001, formerly CUMV 96811, JPS- 1122, 162 mm SL. (–0.841, 12.965): J.P. Sullivan & B. Sidlauskas, 17 September 2014: CUMV 98129, JPS- 1179, 121.5 mm SL; AMNH 264796, formerly CUMV 98132, JPS- 1183, 126 mm SL; MNHN 2016-0017, formerly CUMV 98133, JPS- 1184, 125.5 mm SL; MRAC 2016-010 -P-00002, formerly CUMV 98141, JPS- 1198, 137 mm SL; CUMV 98142, JPS- 1199, 137.5 mm SL; AMNH 264797, formerly CUMV 98144, JPS- 1202,133 mm SL.
Upper Ogooué River (12) Under bridge near Franceville (1.637°S, 13.530°E) C.D. Hopkins et al., 7 August 1999. (9): AMNH 264798, formerly CUMV 80463, tag no. 3465, 7 August 1999; MNHN 2016-0018, formerly CUMV 80463, tag no. 3466, 132 mm SL; MRAC 2016-010 -P-00003, formerly CUMV 80463, tag no. 3467, 157 mm; CUMV 96850 (6, specimen nos. JPS- 1095, JPS-1099 = AMNH 264799 JPS-1102, JPS-1103, JPS-1104, JPS-1105) 116–137 mm SL, J.P. Sullivan, 27 May 2011.
Ogooué River, 30 minutes downriver from bridge near Franceville (1.603°S, 13.529°E): 14 August 1999. (3); MNHN 2016-0020, formerly CUMV 80507, tag no. 3667, 157 mm SL.; CUMV 80507, tag no. 3671, 187 mm SL; CUMV 80507, tag no. 3720, 139 mm SL.
Non-type specimens used for phylogenetic analysis: Okano River near Mitzig (0.80983°N, 11.64633°E): AMNH 231500 (specimen no. 4149, referred to as B. cf. curvifrons in Sullivan et al., 2004), J.P. Sullivan et al., 2001-08-17.
Non-type specimens used for analysis of EODs: Doumé rapids, left bank of Ogooué River (0.841° S, 12.965° E): J.P. Sullivan, 16 September 2014: CUMV 98092 (1, specimen no. JPS-1176) 154 mm
SL, EOD no. 197457. J.P. Sullivan, 17 September 2014: CUMV 98127 (1, specimen no. JPS-1177) 162 mm SL, EOD no. 197458. CUMV 98128 (1, specimen no. JPS-1178) 147 mm SL, EOD no. 197459. CUMV CUMV 98143 (1, specimen no. JPS-1200) 150 mm SL, EOD no. 197481.
Sébé River, left bank rocks below bridge (0.93442°S, 13.35777°E): J.P. Sullivan, 20 September 2014: CUMV 98261 (1, specimen no. JPS-1217) 111 mm SL, EOD no. 197494. CUMV 98086 (1, specimen no. JPS-1222) 122 mm SL, EOD no. 197499. CUMV 98087 (1, specimen no. JPS-1224) 135 mm SL, EOD no. 197501. CUMV 98088 (1, specimen no. JPS-1225) 147 mm SL, EOD no. 197502. CUMV 98089 (1, specimen no. JPS-1228) 152 mm SL, EOD no. 197505. CUMV 98090 (1, specimen no. JPS-1229) 177 mm SL, EOD no. 197506. J.P. Sullivan, 22 September 2014: CUMV 98077 (1, specimen no. JPS-1241) 136 mm SL, EOD no. 197518. CUMV 98080 (1, specimen no. JPS-1242) 133 mm SL, EOD no. 197519. CUMV 98081 (1, specimen no. JPS- 1243) 146 mm SL, EOD no. 197520. CUMV 98078 (1, specimen no. JPS-1244) 141 mm SL, EOD no. 197521. CUMV 98079 (1, specimen no. JPS-1245) 146 mm SL, EOD no. 197522.
98130 (1, specimen no. JPS-1182) 132 mm SL, EOD no. 197462. CUMV 98131 (1, specimen no. JPS-1182) 163 mm SL, EOD no. 197463. CUMV 98134 (1, specimen no. JPS-1185) 176 mm SL, EOD no. 197466. CUMV 98135 (1, specimen no. JPS-1186) 162 mm SL, EOD no. 197467. CUMV 98136 (1, specimen no. JPS-1187) 165 mm SL, EOD no. 197468. CUMV 98137 (1, specimen no. JPS-1188) 144 mm SL, EOD no. 197469. CUMV 98139 (1, specimen no. JPS-1191) 116 mm SL, EOD no. 197472. CUMV 98140 (1, specimen no. JPS-1197) 145 mm SL, EOD no. 197478.
Diagnosis: Paramormyrops ntotom sp. nov. is distinguished from all other Lower-Guinea Paramormyrops by a combination of morphological and electrical characteristics: 5 teeth in upper-jaw, 6 in lower; 12 circumpeduncular scales; ‘V’-shaped snout profile viewed from above, snout angle 38–50° (Fig. 5D), corresponding to an interorbital width 0.8–1.05 times the snout length; BD 14.9–18.1% SL, 81–91.6% of BD at urogenital pore (Fig. 5E); eye diameter 12.4–14.7% HL measured to end of opercular bone (Fig. 5F); snout length 23.8–28.3% HL; ratio of HL to depth (HLx/ HDx measured from radiographs) 1.25–1.40 (Fig. 4A); HL 20.4–24.6% SL; EOD waveform with two phases, head positive then negative, duration 4.78 ± 1.10 ms with a corresponding peak power spectral frequency, 265 ± 67 Hz; electric organ composed of type NPp electrocytes (Sullivan et al., 2002).
Comparison with other Paramormyrops: With its 5/6 teeth, 12 circumpeduncular scales and sharp snouts, P. ntotom sp. nov. differs from all other described Paramormyrops except P. curvifrons and P. sphekodes. We treat both of these in turn.
Four morphological characters distinguish P. ntotom sp. nov. from P. curvifrons. (1) ratio of HL to SL shorter in P. ntotom sp. nov. compared with P. curvifrons (Fig. 5A); (2) slight concave depression in the forehead in advance of the orbit and a relatively compact snout compared to P. curvifrons which has a longer snout, downward sloping, often with a slightly protruding chin and upper lip; (3) shorter prepectoral distance relative to predorsal distance (Fig. 5B); (3) snout angle greater in P. ntotom sp. nov. than P. curvifrons (Fig. 5D, G) and (4) the HD relative to HL greater in P. ntotom sp. nov. than P. curvifrons (Fig. 5C).
EOD duration slightly longer in P. ntotom sp. nov. compared with P. curvifrons, with extensive overlap (Fig. 15). Both species have type NPp electrocytes in the electric organ and both exhibit sex differences in EOD duration (Table 3, Fig. 15). Although these two species have overlapping EOD types, our collections indicate they are not anywhere sympatric. Paramormyrops curvifrons is known only from the Ivindo River in Gabon, while P. ntotom sp. nov. is known only from the Ogooué (Fig. 10).
Paramormyrops ntotom sp. nov. differs from P. sphekodes in the six following morphological characters: (1) larger overall size at sexual maturity (Fig. 2); (2) head more elongate and less rounded (Fig. 4); (3) snout reduced (Fig. 3, Fig. 5G); (4) larger caudal peduncle depth to length ratio (Fig. 3, Table 2); (5) the smaller eye diameter relative to HL, HLBO (Fig. 5F, Table 2); and (6) the greater EOD duration (Figs 2, 14).
When alive, P. ntotom sp. nov. is most easily distinguished from P. sphekodes by its longer EOD duration and a correspondingly lower peak spectral frequency (Table 3, Figs 8, 14, 15). The EODs of P. ntotom sp. nov. and P. sphekodes also differ in shape, with the width of first and second phase being equal for P. ntotom sp. nov., while W1 is longer than W 2 in P. sphekodes (Fig. 15). Living specimens of these two species also differ in coloration. Dorsal and anal fin pigmentation tends to be darker in P. ntotom sp. nov. than P. sphekodes, and the ground color of the skin tends to be darker chocolate brown compared to yellow brown in P. sphekodes (Fig. 7).
Description: Photos and radiograph of the holotype are shown in Fig. 12. Table 2 summarizes morphometric ratios and meristics for it and 22 paratypes. Figure 13 shows five live specimens photographed in the field.
A large-bodied Paramormyrops, largest female, 137.5 mm SL (CUMV 98142, #JPS-1199), the largest male, 183 mm SL (CUMV 80507, #3671). Body laterally compressed with maximum width at opercular bones, 8.43–10.42% SL. Viewed laterally, BD increases gradually from base of the pectoral fin to its maximum at origin of the anal fin. BD at pectoral fin, 14.9–18.1% SL, BD at urogenital pore (BDUGP) 16.7–21.5% SL: the ratio of these two depths, 0.819 –0.916, reflects the slight increase posteriorly compared to P. sphekodes (Table 2). BD decreases from origin of dorsal and anal fins to caudal peduncle. Caudal peduncle length 15.8– 19.4% SL, slightly deeper at origin than centre, CPD 26.1–33.7% CPL. Lobes of caudal fin rounded.
Lateral head profile straight and downward sloping from a point half way between opercular opening and tip of the snout, slightly concave above the eye in some specimens. Head and snout ‘V’-shaped when viewed dorsally (Figs 9D and 15), snout angle, 38–50° intermediate between that of P. curvifrons and P. sphekodes (Fig. 5D, G, Table 2). HL, 19.6–24.6% SL, similar to P. sphekodes, but shorter than P. curvifrons (Fig. 5A). HD measured from external landmarks 64.8–79.8% HL, or HL/HD = 1.13–1.35. When measured from radiographs, HLx/HDx = 1.25–1.38, non-overlapping with P. sphekodes (Fig. 4). HW 38.3–46.9% HL. In lateral view, snout tip lies along mid-horizontal line. Teeth bicuspid, 5 (rarely 4) in upper and 6 in lower jaws.
Mouth small, rictus directly beneath nares. Chin slightly swollen below gular region, not extending beyond snout. Eye small, ED 10.6–15.0% HL (Fig. 5F). Eye socket forms light ring around dark eyeball, with gold iris and dark centre. IOW 22.4–31.4% HL. Anterior naris at about 1/3 distance from snout tip to eye, slightly below line drawn through centre of eye, posterior naris halfway between anterior naris and eye, level with lower margin of eye. Opercular opening begins anterior to base of pectoral fin. POL 62.8–68.1% HL.
Pectoral-fin origin beneath posterior terminus of opercular opening, slightly below mid-horizontal line, pectoral length 14.6–16.8% SL, 10–12 rays. Pelvic-fin origin at 34.6–38.8% SL, length 8.2–11.1% SL, positioned ventrally, 6 rays. Pre-dorsal distance 61.4–66.1% SL; anterior margin of dorsal fin gently convex, trailing margin concave in first third, remainder levels off at 1/2 DFH. Maximum DFH 59.0–83.2% DFL, 19–21 total rays. Anal-fin origin slightly anterior to dorsal-fin origin: dorsal-fin origin above seventh anal ray (fifth branched ray).
Anal fin mirrors general shape of dorsal fin, maximum height 50.4–71.8% AFL. In males, anterior AFR thickened and stiff, noticeable notch in body spanning anterior half of anal-fin base. Anal-fin base terminus directly beneath that of dorsal fin, rays 24–26. Lobes of caudal fin rounded, equal, slightly wider than caudal peduncle, deeply cleft, scaled at the bases.
Scales fine, cycloid, absent from head. Pierced lateral line scales 57–72, 9–12 scale rows between anterior base of dorsal fin and lateral line, 10–14 scale rows from pelvic fin to lateral line. Circumpeduncular scales 12.
Vertebrae: 41–44 total, 18 pre-caudal and 22–26 caudal.
The EODs of P. ntotom sp. nov. differ between males and females (Figs 2 and 14C) with a corresponding difference in EOD power spectrum (Figs 2 and 14E). EOD duration of males, significantly longer than that for females (Student’s t = 2.107, P <0.05, Table 3). Widths of the first and second peaks nearly equal in P. ntotom sp. nov. both for males and females (Table 3) contrasting with P. sphekodes where the first peak is longer than the second, especially for males. Variation in EOD duration amongst male P. ntotom sp. nov. results from EOD elongation during male sexual maturation – only appearing in the larger males during the breeding season. Adult males and females recorded during the dry season have similar EODs, a common pattern among mormyrids studied in the laboratory (Kirschbaum, 1984, 1987) and in the field (Bass et al., 1983).
Coloration. All fins with lightly to heavily pigmented rays, membranes hyaline. No dark band bases of dorsal and anal fins. Body darker dorsally, lighter ventrally. When alive, tan to light chocolate brown body with olive accents on top of head, back and belly. Mouth, chin and sometimes gular region unpigmented, white to grey. Many small white pores (mormyromast and ampullary electroreceptors) visible on top of head and back, with fewer, large white pores (Knollenorgans) on head. Preserved specimens are uniform greyish-brown.
Electric organ discharge. EOD composed of biphasic pulses, head positive then negative, total duration, 4.79 ± 1.1 ms (Fig. 14A, C; Table 3). Width, W1, of first peak 2.25 ± 0.429 ms, approximately equal to width of second peak (Table 3). Power spectrum peak, 265 ± 67 Hz. Other quantitative measures in Table 3 and Fig. 14. Marked inflection point on first rising phase of EOD in advance of peak P1; first derivative of EOD with two positive peaks before P1 (Fig. 14B, arrows 1 and 2), contrasting with P. sphekodes, which lacks an inflection point and has but a single peak in the first derivative (Fig. 8B). No head-negative peak in advance of P1 (see 20× expanded trace in Fig. 14A) as occurs in all mormyrids with Type Pa electrocytes (P enetrating stalks with a nterior innervation), indicating that electrocytes are type NPp (i.e. have N on- P enetrating stalks with p osterior innervation), the same as P. sphekodes (not shown).
Distribution: Paramormyrops ntotom sp. nov. is found in Gabon in the Ogooué River and some of its tributaries (Fig. 10). We have confirmed its presence in the lower Ogooué near Lambaréné, the Okano River near Mitzig, the middle Ogooué near Lopé and the upper Ogooué from Doumé to Franceville. This species is notably missing from the Ivindo River, a major tributary of the Ogooué to the North East of Gabon, connected to the Ogooué through a series of major waterfalls.
Etymology: The species name, ntotom is the word for mormyrid fish in the language of the Fang people from northern Gabon, Equatorial Guinea and southern Cameroon.
description: Published as part of Rich, Madeline, Sullivan, John P. & Hopkins, Carl D., 2017, Rediscovery and description of Paramormyrops sphekodes (Sauvage, 1879) and a new cryptic Paramormyrops (Mormyridae: Osteoglossiformes) from the Ogooué River of Gabon using morphometrics, DNA sequencing and electrophysiology, pp. 613-646 in Zoological Journal of the Linnean Society 180 on pages 628-638, DOI: 10.1093/zoolinnean/zlw004, http://zenodo.org/record/5711034