How to Identify Smooth Lumpsucker

To identify Smooth Lumpsucker (Aptocyclus ventricosus), look at these key features.

Physical Characteristics

Body shape

rounded

Coloration

Variable, typically ranging from reddish-brown to purplish-brown, often with mottled patterns. Juveniles can be lighter, sometimes greenish or yellowish. The ventral surface is often paler.

Scale type

none

Mouth position

terminal

Distinctive features

Absence of prominent bony tubercles or plates on the body, giving it a smooth, gelatinous texture, unlike most other lumpsuckers., Large, bulbous head and body., Prominent suctorial disc (pelvic fin modified into a sucking disc) on the ventral side., Small, widely spaced eyes., Small, fleshy papillae may be present on the head and body, but not bony tubercles.

Dorsal fin

Two dorsal fins, the first often embedded or reduced, the second well-developed and fleshy. The first dorsal fin is often hidden by thick skin in adults.

Tail fin

Rounded to truncate caudal fin.

Pectoral fin

Large, fan-like pectoral fins.

Distinctive fins

Pelvic fins are modified into a prominent, powerful suctorial disc located on the ventral surface, used for attaching to substrates.

Identification Tips

1. 1

   Body Surface

   The most distinguishing feature is its smooth, gelatinous skin, lacking the bony plates or tubercles characteristic of most other lumpsucker species. This is crucial for differentiation.

2. 2

   Suctorial Disc

   Presence of a large, well-developed sucking disc on the underside, formed from modified pelvic fins, used for attachment to rocks or other surfaces.

3. 3

   Body Shape

   Globular, somewhat pear-shaped body, with a large head and tapering towards the tail.

4. 4

   Coloration

   Observe the overall reddish-brown to purplish-brown coloration, often mottled, which helps it blend with rocky or muddy substrates.

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