Hypoptopoma baileyi, Aquino, Adriana E., 2010

Aquino, Adriana E., 2010, Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae), Bulletin of the American Museum of Natural History 2010 (336), pp. 1-110 : 23-28

Hypoptopoma baileyi , new species Figure 18 , table 1

HOLOTYPE: AMNH 39828 (♀, 38.9 mm SL) Bolivia: Beni, backwater, Río Itenez , 10 km SE Costa Marques, Brazil; collected by R.M. Bailey and R. Ramos, 10 September 1964.

PARATYPES (collected with holotype): AMNH 243579 (61 ♀ + 18 ³, 27.5–44.0 mm SL). UMMZ 205171 (75 ♀ + 32 ³, 6 cs, 27.7– 40.6 mm SL).

OTHER MATERIAL EXAMINED: BOLIVIA, Beni: AMNH 39764 (1 ♀, 25.5 mm SL) Río

.

H

,

F

; steindachneri

.

H

,

E

; gulare

.

H

,

D

; guianense

.

H

,

C

; psilogaster

.

H

.

B

; thoracatum

.

H

,

A

: fin caudal the

of pattern. Pigmentation. machadoi , H G;

17 Fig

.

. elongatum

Itenez, 3 km SE Costa Marques , Brazil ; AMNH 39788 (8 ♀ + 1 ³, 3 cs, 26.6–33.9 mm SL) Río Itenez , 9 km SE Costa Marques, Brazil ; AMNH 39841 (4 ♀, 27.7–32.9 mm SL) Oxbow Río Itenez , 9 km SE Costa Marques, Brazil ; AMNH 39861 (27 ♀ + 7 ³, 24.9–41.5 mm SL) Río Itenez , 9 km SE Costa Marques, Brazil ; SIUC 30815 (12 ♀, 29.7– 35.4 mm SL) Río Matos in Estación Biológica del Beni (bridge nearest entrance, 6 km E of EBB on road to San Ignacio). Santa Cruz: AMNH 229206 (2 ♀, 29.7–31.8 mm SL) Noel Kempff Mercado Nacional Park , Río Paucerna , about 500 m upstream from mouth at Río Itenez ; AMNH 229310 (2 ♀, 28.5– 33.3 mm SL) Noel Kempff Mercado Nacio- nal Park, Río Itenez , Bahía Piuba at mouth ; AMNH 229353 (17 ♀ + 2 ³, 25.1–37.6 mm SL) Noel Kempff Mercado Nacional Park, Río Itenez, beach about 200 m upstream from Bahía Agua Blanca ; CBF 2859 (1 ♀ + 1 ³, 33.7–43.7 mm SL) Guarayos, Perseverancia, Río Negro .

DIAGNOSIS: Hypoptopoma baileyi is distinguished from all congeners except H. muzuspi by having trunk pigmentation in the form of a lateral band that is progressively darker along medial, midventral, and ventral series of plates, and a caudal-fin pigmentation pattern formed by 6–8 narrow dark brown bars and a dark spot at the base of the lower lobe. Hypoptopoma baileyi is distinguished

TABLE 1 Morphometric and Meristic Data for Hypoptopoma baileyi Holotype: AMNH 39828. Paratype: AMNH 243579.

from H. muzuspi by having preopercle reduced, not reaching hyomandibular-opercle condyle (vs. preopercle not reduced, reaching to hyomandibular-opercle condyle) and absence of canal in preopercle (vs. presence of canal in the preopercle) (fig. 14A).

DESCRIPTION: Morphometric and meristic data presented in table 1. Body size relatively small, moderately elongate, and depressed; greatest body depth at dorsal-fin origin. Dorsal profile of head and body from tip of snout to dorsal-fin origin straight, slightly angled dorsally at anterior supraoccipital tip; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid dorsally not visible. Snout slightly rounded in dorsal view, concave at region anterior to naris. Posterior surface of bony pit of nasal organ gradually inclined. Body cross section between pectoral- and pelvic-fin origins ovoid to transversely depressed, progressively compressed posterior to anal-fin base.

Eyes moderately large, positioned slightly closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located close to ventral surface of head. Dorsal interorbital distance shorter than ventral interorbital distance.

Total plates in lateral medial series 22–23 (23). Dorsal series 19–21 (20); middorsal series 3–4 (4); midventral series 12–14 (13), with four plates anterior of first plate of ventral series; ventral series 19–21 (20). Second plate of midventral series contacting single plate of medial series.

Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right side series, 3–9 each; medial series of 3–8 (6) roughly squared plates; anterior azygous plate absent; medial series occasionally absent, in which case paired series make contact along midline in fully developed individuals. Single anal plate present. Thoracic plates absent. Preopercular canal absent. Posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital smooth; pore between canal-bearing ventral plate and fourth infraorbital absent.

Small odontodes evenly distributed on head, roughly arranged in closely spaced longitudinal lines. Odontodes ventral to tip of snout slightly enlarged. Lamina of trunk plates with longitudinal rows of odontodes, becoming progressively smoother ontogenetically; largest specimens maintain longitudinal rows dorsal to lateral-line canal, rows otherwise absent; distinct column of marginal odontodes on posterior plate border in mature adults.

Total vertebrae 27–28; ribs present. Premaxillary teeth 14–22; dentary teeth 11–18. Maxillary barbels short, not reaching to anterior margin of ventral canal-bearing plate.

Dorsal-fin origin located slightly posterior of vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through midpoint of anal-fin length. Pectoral fin reaching to vertical through midpoint along pelvic-fin spine. Depressed pelvic fin close or reaching to plate anterior to anal-fin spine. Extension of serrae along length of pectoral-spine margin, except for short basal segment; serrae of oblique type. Pelvic fin short, unbranched slightly shorter than first branched rays. Depressed fin reaching to anus, not reaching to insertion of anal-fin spine. Caudal fin forked. Adipose fin absent.

COLOR IN ALCOHOL: Ground color tan to pale ochre. Melanophores light to dark brown on trunk and particularly clustered at base of plates resulting in mottled appearance. Melanophores slightly more concentrated on compound pterotic dorsal to swimbladder capsule, anterior half of supraoccipital, frontals, plate anterior to naris, lateral rostral plates on snout, on posterior half of lip surface, band on maxillary barbel, anterior half of branchiostegal membrane, and posterior tip of naris flap. Melanophores scattered or absent on dorsal surface of mesethmoid, anterior rostral plate, and narrow band anterior to epiphysial branch of supraorbital canal in frontal. Deep-lying melanophores arranged in narrow transverse bands posterior to dorsal-fin base, noncoincident with posterior margin of plates. Midlateral stripe situtated along medial, midventral, and ventral series of plates, progressively less pigmented toward ventral surface of body, which is mostly unpigment- ed except for scattered melanophores on posterior portion of trunk, soft tissue along base of pectoral and anal fins, anterolateral margin of cleithra and posterior tip of cleithral process, ventral canal-bearing plate, and lateral portions of lateral abdominal series. Paired and unpaired fins with relatively numerous narrow dark brown bands. Series of lanceolate plates at base of caudal fin and small posteriormost plate of trunk medial series more densely pigmented with black melanophores. Last 1–2 posteriormost plates of dorsal and ventral trunk series less pigmented, whitish. Upper and lower marginal and branched rays of caudal-fin with 7– 10 bands of brown melanophores, with slightly darker area at base of lower lobe.

SEXUAL DIMORPHISM: Male urogenital papilla elongate, slender papilla covered by flaplike anus. Males with patch of tightly arranged small odontodes on second, third, and fourth plates of ventral series, lateral to urogenital papilla. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.

DISTRIBUTION: Río Iténez, in the upper Rio Madeira basin, along the border between Bolivia and Brazil (fig. 19).

ETYMOLOGY: The specific epithet baileyi is a patronym honoring Reeve M. Bailey (1911–2000), who collected the specimens of the new species in 1964 during an expedition of the AMNH to the Río Itenez.

Figures

Fig. 18. Hypoptopoma baileyi, holotype, AMNH 39828, 38.9 mm SL female, in dorsal, lateral, and ventral views.