Lophiobrycon weitzmani Castro, Ribeiro, Benine & Melo, 2003

Menezes ¹, Naércio A. & Weitzman ², Stanley H., 2009, Systematics of the Neotropical fish subfamily Glandulocaudinae (Teleostei: Characiformes: Characidae), Neotropical Ichthyology 7 (3), pp. 295-370 : 305-308

Lophiobrycon weitzmani Castro, Ribeiro, Benine & Melo, 2003

Figs. 3-4

Lophiobrycon weitzmani Castro, Ribeiro, Benine & Melo 2003: 14 , figs. 1-9 (type locality: as given below for holotype; phylogenetic considerations; biogeography). - Weitzman et al., 2005: 344, 345, 347 (presence of club cells; comments on insemination; phylogenetic relationships). - Langeani et al., 2007: 184 (size; origin and occurrence in the upper rio Paraná). - Menezes, in Buckup et al., 2007: 38 (listed in catalog; distribution; conservation status).

Diagnosis. Same as the distinguishing characters given in the diagnosis of Lophiobrycon above.

Description. Table 2 presents morphometrics of holotype and paratypes. Body compressed, relatively deep, especially near dorsal-fin origin; body deepest at vertical through pelvic-fin origin. Predorsal profile relatively arched in adult males, less so in females and immatures in which predorsal profile gently convex to tip of snout. Dorsal profile strongly arched in males, less so in females and juveniles, nearly straight along dorsal-fin base and to origin of dorsal procurrent rays. Dorsal-fin origin nearer to snout tip than to caudal-fin base. Ventral profile of body strongly convex in adult males from anterior tip of lower jaw to origin of pelvic fins, less convex in females and juveniles. Abdominal profile in adult males slightly concave to anal-fin origin, straight or nearly so in females and juveniles. Body profile along anal-fin base in males slightly concave anteriorly in region of anterior lobe of anal fin, straight or nearly so along remainder of fin base in males. Profile straight along entire anal-fin base in females and juveniles.

Lower jaw protruding, extending slightly anterior to tip of upper jaw. Lower jaw of adult males thick and heavy compared to that of females and juveniles. Mouth angled posteroventrally. Maxilla extends posteriorly to point slightly anterior of vertical through anterior border of pupil.

Dorsal-fin rays ii, 8 (in all specimens, n = 54); posterior ray split to its base and counted as one ray. Adipose fin unusually long in adult males (see Castro et al., 2003: 5, fig. 1a). Anal-fin unbranched rays iii-iv (iv), 20-23 (20), 21.8, n = 54; posterior ray split to its base and counted as 1 ray. Anal fin with

Males Females

Characters

Holotype N Range Mean SD N Range Mean SD dif.

Standard length 26.0 22 14.8-30.0 22.2 32 13.5-25.0 18.9

Depth at dorsal-fin origin 37.7 22 30.4-55.7 36.0 5.1 32 30.0-36.7 33.6 2.1 – Snout to dorsal-fin origin 50.0 22 49.1-56.3 52.5 2.1 32 53.2-56.6 54.9 1.1 + Snout to pectoral-fin origin 25.0 22 23.6-28.7 26.0 1.5 32 25.0-28.9 26.4 1.1 – Snout to pelvic-fin origin 46.9 22 44.3-51.9 46.8 1.6 32 45.0-50.3 47.4 1.5 – Snout to anal-fin origin 57.7 22 54.7-63.3 59.2 1.9 32 55.6-65.0 61.0 1.9 – Caudal peduncle depth 17.3 22 13.1-17.4 15.6 1.5 32 12.8-16.0 14.6 1.0 + Caudal peduncle length 12.3 22 08.8-14.8 11.1 1.3 32 08.4-12.1 10.3 1.0 – Pectoral-fin length 30.8 22 22.1-33.5 27.3 3.4 32 16.8-25.7 23.0 2.0 + Pelvic-fin length 21.9 22 13.5-24.4 19.7 3.9 32 13.3-17.3 15.7 1.0 + Dorsal-fin base length 16.2 22 13.5-19.1 15.6 1.4 32 12.8-15.9 14.1 0.8 + Dorsal-fin height 27.7 22 26.0-29.8 27.3 1.3 32 23.2-28.0 25.8 1.1 + Anal-fin base length 32.3 22 29.9-34.5 32.2 1.2 32 22.2-33.1 29.2 3.3 + Anal-fin lobe length 28.9 22 21.6-29.4 26.1 2.4 32 15.0-26.0 23.3 1.9 +

Eye to dorsal-fin origin 38.8 22 37.0-44.3 40.1 1.9 32 40.4-45.5 42.5 1.5 + Dorsal-fin origin to caudal-fin base 55.4 22 49.3-56.7 52.5 2.3 32 48.1-53.4 50.1 1.3 + Bony head length 26.9 22 26.0-30.2 28.0 1.3 32 27.3-30.7 29.0 0.9 – Horizontal eye diameter 40.0 22 36.1-41.9 38.3 1.7 32 35.8-41.9 38.9 1.6 – Snout length 22.9 22 18.6-23.8 21.2 1.5 32 17.1-23.2 20.2 1.4 – Least interorbital width 32.9 22 30.6-36.2 33.4 1.4 32 29.3-34.8 32.6 1.3 – Upper jaw length 37.1 22 34.7-42.3 38.1 2.3 32 34.1-38.7 36.7 1.2 –

moderately developed lobe anteriorly ( Figs. 3 , 4 and 6 ); lobe includes third or fourth unbranched ray and first six branched rays. Anal fin of sexually mature males with hooks distributed on last unbranched ray and anterior five branched rays ( Fig. 6 ). Pectoral-fin unbranched ray i in all specimens, branched rays 11-14 (12), 12.3, n = 54; tip of pectoral-fin extends to origin of pelvic fin; fins longer in mature males than in mature females. Middle portions of unbranched and first branched pectoral-fin rays of sexually mature males with thickened lepidotrichia (see Castro et al., 2003: 15, fig. 5). Pelvic-fin rays i, 6 (in all specimens, n = 54). First (unbranched) ray of pelvic fin bearing small hooks ( Fig. 7 ). Principal caudal-fin ray count 10/9, (n = 54).

Scales cycloid; lateral line incomplete, perforated scales 1-7 (4), 5, n = 54. Lateral series scales 30-36 (31), 32.7, n = 49. Predorsal scales 13, 12.8, n = 50. Scale rows between dorsal-fin and anal-fin origin 12-13 (12), 12.3, n = 54. Scale rows around caudal peduncle 14-15 (14), 14.4, n = 47.

Oral teeth form and arrangement as described and illustrated by Castro et al. (2003: 15, fig. 6). Outer row premaxillary teeth 1-3 (2), 1.9, n = 54; inner row 5-7 (5), n = 54. Maxillary teeth 3-7 (6), 4.4, n = 54. No significant difference in tooth number between females and males.

Vertebrae 33-35 (34), 34.4, n = 35. Dorsal limb gill rakers 5- 7 (6), 5.8, n = 54; ventral limb gill rakers 8-10 (10), 9.3, n = 54. Branchiostegal rays 4 in cleared and stained specimens, 3 rays originating on anterior ceratohyal and 1 on posterior ceratohyal.

Color. The preserved color pattern of males and females as well as life colors described and illustrated by Castro et al. (2003: 15, figs. 1 and 2).

Sexual dimorphism. In addition to the sexually dimorphic features discussed by Castro et al. (2003: 15-16) males have hooks on at least first pelvic-fin ray that are absent in females and lack urogenital papilla ( Figs. 3 and 7 ). Females have a urogenital papilla with a posterior opening and the anus located at its base ( Fig. 8 ). This papilla is rudimentary in immature females (13.5-16.5 mm SL) and well developed in mature females (18.0-25.0 mm SL). Castro et al. (2003: 15) found differences in body depth, caudal peduncle depth and pectoral-fin length between males and females of L. weitzmani with increasing SL as they become sexually mature and increase in length. Our criteria to differentiate males and females led us to a different proportion between sexes than that obtained by Castro et al. (2003). With our results shown in Table 2 only pectoral-fin length and pelvic-fin length showed significant dimorphic differences in regression analysis as shown in Figs. 9 and 10 . Males reach greater lengths than the females in the available samples with divergence between the sexes in the two dimorphic characters starting at about 20 mm SL.

Distribution. Lophiobrycon weitzmani is endemic to headwater streams in the middle stretch of the rio Grande basin in the upper rio Paraná basin. See fig. 3 in Castro et al. (2003), and fig. 3 in Menezes et al. (2008).

Material examined. Holotype. LIRP 4366 , male, 26.0 mm SL, Brazil, Minas Gerais, rio Grande basin, município de Delfinópolis, estância Carmen Sílvia, córrego Bom Jesus, 20º12’10”S 46º22’W . Paratypes. Collected with holotype: LIRP 4337 , 8 , 19.7 -27.0 mm SL, 1 male C&S, 4 adult females, 19.7- 22.0 mm SL, 1 immature male, 27.0 mm SL, 1 adult male, 25.5 mm SL ; LIRP 4338 , 8 adult males, 22.0-30.0 mm SL, 4 immature males, 15.0-24.0 mm, 11 adult females, 17.8-25.0 mm SL, 3 immature females, 13.5-16.5 mm SL ; MZUSP 83353 , 2 adult males, 25.8 and 26.5 mm SL, 5 immature males, 14.8-17.6 mm SL, 5 mature females, 18.0- 21.2 mm SL, 8 immature females, 15.0-21.8 mmSL .

Figures

Fig. 3. Lophiobrycon weitzmani, paratype, adult male, LIRP 4338, 33.1 mm SL, Brazil, Minas Gerais, rio Grande basin, upper rio Paraná, município de Delfinópolis, Estância Carmen Sílvia, córrego Bom Jesus. Modified from Castro et al. (2003).

Fig. 4. Lophiobrycon weitzmani, paratype, adult female. MZUSP 83353, 21.8 mm SL; same locality data as in Fig. 3.

Fig. 6. Lophiobrycon weitzmani, paratype, adult male, LIRP 4338, 33.1 mm SL; anal-fin rays with hooks, lateral view, left side.

Fig. 7. Lophiobrycon weitzmani, paratype, adult male, LIRP 4338,33.1mm SL;pelvic-fin rays,ventralview, left side,anterior at left.

Fig. 8. Lophiobrycon weitzmani, paratype, mature female, MZUSP83353, 18.2mmSL; urogenitalpapillaof mature female, lateral view, left side, anterior at left.

Fig. 9. Lophiobrycon weitzmani. Pectoral-fin length as function of standard length for males and females.

Fig. 10. Lophiobrycon weitzmani. Pelvic-fin length as function of standard length for males and females.