Creagrutus

Creagrutus aff, 158, 177

paralacus, Creagrutus, 2, 77, 208

Paraphago, 19

Parodon, 24

pearsoni, Creagrutus, 2, 48, 77, 178–181

pellegrini, Chalceus, 43

Creagrutus, 2, 43

peruana, Creagrutus, 181, 183

Piabina, 181

peruanus, Creagrutus, 2, 48, 90, 181–184

petilus, Creagrutus, 3, 48, 184–186

Phago, 19

phasma, Creagrutus, 3, 48, 81, 137, 186–189, 220

Piabarchus, 4, 42

analis, 42, 224

torrenticola, 42

Piabina, 4, 223–224

analis, 42, 224

argentea, 49, 224–228

beni, 78, 178, 180

peruana. 181, 183

piquira, 3, 224, 226

Creagrutus aff. mulleri.—Barriga, 1982:64

DIAGNOSIS.—The possession of premaxillary dentition with the three components generalized for the species of Creagrutus, but with a distinct gap between the first and second teeth of primary tooth row and a forward position of the triangular cluster of three posteromedial teeth distinguishes C.muelleri from all members of the clade formed by Creagrutus and Piabina with the exception of Creagrutus maracaiboensis, C. melanzonus, C. nigrostigmatus, C. ouranonastes, C. peruanus, C. runa, and Piabina argentea. Creagrutus muelleri can be distinguished from these seven species by the combination of the possession of 39 to 41 lateral line scales, 11 to 13 predorsal median scales, 10 to 12 branched anal-fin rays, 39 or 40 vertebrae, the relatively wide third infraorbital nearly contacting the horizontal and vertical limbs of the preopercle, the distance from the snout to the anal-fin origin (60.1%–65.6% of SL), the anal- fin length (15.3%–17.8% of SL), the caudal peduncle depth (11.7%–13.4% of SL), the bony orbital diameter (24.9%–29.7% of HL), and the absence of two small distinct spots of dark pigmentation on the basal portion of the caudal fin.

DESCRIPTION.—Morphometric andmeristic data for Creagrutus muelleri in Table 39. Overall body relatively robust, particularly anteriorly. Greatest body depth at vertical through dorsal-fin origin in specimens of approximately 30 mm SL, shifting somewhat anterior of that point in larger individuals, more notably in specimens with distended abdomens. Dorsal profile of head smoothly curved from margin of upper lip to vertical through posterior nostril, straight, or nearly so, from that point to rear of supraoccipital spine. Dorsal profile of body gently convex from rear of supraoccipital spine to dorsal-fin origin at all body sizes, convexity somewhat more pronounced in larger examined specimens. Profile posteroventrally angled along dorsal-fin base and nearly straight from posterior of dorsal-fin base to caudal peduncle in smaller specimens. Changes in profile at anterior and posterior insertions of dorsal fin less notable in larger specimens. Ventral profile of head convex, with barely apparent obtuse angle at anteroventral region of dentary. Ventral profile of body between isthmus and pelvic fin convex; convexity more pronounced in larger specimens.

Characters A B

Morphometrics

Standard length 82.535.1–108.3

1. Snout to anal-fin origin 61.7 60.1–65.6

2. Snout to pelvic-fin insertion 44.7 43.0–48.3

3. Snout to pectoral-fin insertion 23.9 21.6–25.8

4. Snout to dorsal-fin origin 49.8 47.3–51.0

5. Dorsal-fin origin to hypural joint 56.1 53.7–58.9

6. Dorsal-fin origin to anal-fin origin 30.7 28.6–31.6

7. Dorsal-fin origin to pelvic-fin insertion 29.0 25.0–29.9

8. Dorsal-fin origin to pectoral-fin insertion 33.1 31.3–35.8

9. Caudal peduncle depth 12.7 11.7–13.4

10. Pectoral-fin length 20.0 19.0–20.9

11. Pelvic-fin length 14.5 14.4–15.7

12. Dorsal-fin length 18.2 17.8–22.4

13. Anal-fin length 16.2 15.3–17.8

14. Head length 25.8 23.7–26.5

15. Postorbital head length 54.0 47.3–54.1

16. Snout length 24.5 24.4–29.4

17. Bony orbital diameter 25.3 24.9–29.7

18. Interorbital width 34.2 30.0–34.8

Meristics

Lateral line scales 41 39–41

Scale rows between dorsal-fin origin and lateral line 4 4–5

Scale rows between anal-fin origin and lateral line 3 3–4

Predorsal median scales 13 11–13

Branched dorsal-fin rays 8 7–81

Branched anal-fin rays 10 10–122

Branched pelvic-fin rays 6 5–63

Pectoral-fin rays 13 12–14

Vertebrae 40 39–40

1Seven branched dorsal-fin rays present in only 1 of 26 specimens.

2Ten and 11 branched anal-fin rays most common, 12 rays present in only 2 of 26 specimens.

3Five branched pelvic-fin rays present in only 1 of 26 specimens.

Head obtusely pointed in lateral view and more obviously pointed in dorsal view. Upper jaw longer than, and slightly overhanging, lower jaw. Anterior portion of snout fleshy, with scattered papillae that extend onto lips and on folds and plicae extending between outer and medial premaxillary teeth. Larger individuals with field of large papillae all over head.

Infraorbital series moderately well developed. Large portion of ventral margin of third infraorbital in contact with horizontal limb of preopercle. Posterior margins of third through fifth infraorbitals not contacting vertical limb of preopercle; gap between infraorbitals and vertical limb of preopercle decreasing slightly dorsally.

Premaxillary teeth in three series: primary row curved, consisting of 5 teeth, with distinct gap between first and second tooth and between medial teeth of contralateral series; triangular cluster of three teeth with anterior tooth approximately same size as teeth of primary row and slightly medial to pronounced gap between first and second teeth of primary row, two other teeth of medial cluster, particularly posteromedial tooth, larger than remaining teeth in jaw; and single tooth of form similar to that of primary series lying lateral to area of contact of third and fourth teeth of primary premaxillary row. Maxilla with 3 or 4 tricuspidate teeth. Dentary with 5 or 6 tricuspidate teeth. Three anterior dentary teeth distinctly larger than other teeth in series, with second tooth slightly larger than first tooth. Third tooth approximately two-thirds height of second tooth. Middle cusp on anterior 3 teeth particularly well developed. Last 2 or 3 teeth on dentary compressed, tricuspidate, and distinctly smaller than third tooth and becoming progressively smaller posteriorly.

Dorsal-fin rays typically ii,8; very rarely ii,7. Dorsal-fin origin at vertical through pelvic-fin insertion. Profile of distal margin of dorsal fin slightly convex in smaller individuals, nearly straight in largest examined specimens. Anal-fin rays ii, 10–12. Profile of distal margin of anal fin very slightly concave. Hooks typically present on anal-fin rays in mature males of many Creagrutus species not present in examined specimens. Pectoral-fin rays i,11–13. Tip of pectoral fin extending posteriorly nearly to pelvic-fin insertion in smaller specimens, only approximately two-thirds of distance in larger specimens. Pelvic-fin rays typically i,6,i, one specimen with i,5,i. Tip of pelvic fin extending posteriorly to anus. Hooks typically present on pelvic-fin rays in mature males of many Creagrutus species not present in examined specimens.

Gill rakers 7–8 + 10–11.

COLORATION IN ALCOHOL.—Ground coloration of specimens collected within the last two decades tan to light brown. Dorsal surface of head with scattered, small, dark chromatophores overlying deep-lying chromatophores over membranes of brain. Region anterior to nostrils somewhat more intensely pigmented, but without distinct crescent-shaped patch of dark pigmentation found in this region in some congeners. Lateral surface of head with scattered, dark chromatophores, chromatophores more concentrated on dorsal portions of opercle and infraorbitals. Body pigmentation darker dorsally, with distinctly darker pigmentation over center of scales dorsally and dorsolaterally. Margins of scales less intensely pigmented, with chromatophores forming dark, reticulate pattern on dorsolateral portions of body. Deep-lying obscure, dark band along midlateral surface of body. Humeral mark irregularly shaped, but vertically elongate overall. Mark ventrally attenuate with somewhat less intensely pigmented region extending up to one-half scale ventral of lateral line. Anterior margin of humeral mark slightly concave.

Margins of fin-rays of dorsal, anal, and caudal fins outlined with small, dark chromatophores, giving fins, particularly caudal fin, dusky overall appearance. Paired fins hyaline to slightly dusky.

ECOLOGY.—Barriga (1982:67) reported that in southeastern Ecuador this species (identified therein as Creagrutus aff. mulleri) inhabits large rivers with strong currents, turbid waters, and muddy bottoms, but within that region it was collected in regions of pebble beaches.

Creagrutus muelleri feeds most commonly on seeds, but some individuals also had fed on insect larvae and fish scales (Barriga, 1982:67). Stomach contents of specimens prepared for clearing and staining in this study consisted of parts of larvae and adult insects, and chopped-up seeds. A female collected in September has ovaries full of eggs.

COMMON NAME.—Southeastern Ecuador: “Blancos” (Barriga, 1982:64).

DISTRIBUTION.—Creagrutus muelleri occurs in the rivers draining the eastern slopes of the Andean piedmont in Ecuador (Figure 67, squares).

MATERIAL EXAMINED.—41 specimens (27, 35.1–108.3).

ECUADOR. “Andes of Western Ecuador,” BMNH 1858.7.25:42, 1 (82.5, lectotype of Leporinus mülleri); BMNH 1858.7.25:43, 1 (78.3, paralectotype of Leporinus mülleri). Tungarahua: N shore of Río Pastaza below town of Río Negro (1°24′S, 78°13′W), KU 20003, 10 (35.1–74.2). Río Pastaza, Hacienda Las Mascota, ANSP 70154, 1 (88.0). Pastaza: Río Pastaza, tributary stream 2 km downstream of Cumandá (1°27′S, 78°08′W), USNM 340984, 10 (6, 38.9–72.5; 2 specimens cleared and counterstained for cartilage and bone). Zamora Chincipe: Río Zamora, near city of Zamora (4°04′S, 78°08′W), MEPN 4637, 1 (57.0); MEPN 4638, 1 (53.3). Río Nangaritza, near village of Guayzimi (4°02′S, 78°40′W), MEPN 4636, 2 (48.2–78.0). Río Nangaritza (3°45′S, 78°36′W), MEPN 6195, 10. Río Zamora above mouth of Río Jamboe (approximately 4°04′S, 78°56′W), USNM 340983, 4 (60.0–108.3; 1 specimen cleared and counterstained for cartilage and bone).

Una especie nueva del genero Creagrutus Guenther del Norte de Colombia. Caldesia, 8(38):353–358

Eigenmann, C.H.

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1911. New Characins in the Collection of the Carnegie Museum. Annals of the Carnegie Museum, 8(1):164–181, plates 1–9.

1912. The Freshwater Fishes of British Guiana, Including a Study of the Ecological Grouping of Species and the Relation of the Fauna of the Plateau to that of the Lowlands. Memoirs of the Carnegie Museum, 5: xii + 578 pages, 103 plates.

1916. New and Rare Fishes from South American Rivers. Annals of the Carnegie Museum, 10(1–2):77–86.

1920. The Fishes of Lake Valencia, Caracas and the Rio Tuy at E1 Concejo, Venezuela. Indiana University Studies, 7(44):1–13.

1922. The Fishes of Western South America, Part 1: The Fresh-Water Fishes of Northwestern South America, Including Colombia, Panama, and the Pacific Slopes of Ecuador and Peru, Together with an Appendix upon the Fishes of the Rio Meta in Colombia. Memoirs of the Carnegie Museum, 9:1–346, 38 plates.

Creagrutus is a genus of characins found mostly in South America, with one species C. affinis extending into Panama in Central America.