Southern Banded Guitarfish: Zapteryx xyster

Family: Trygonorrhinidae
Common name(s)

Southern Banded Guitarfish, Witch Guitarfish.

Identification

A medium sized guitarfish with a wide disc and a short, acutely pointed snout. Snout anterior angle approximately 80º. Rostral ridges widely separated throughout their length. Eyes large. Preorbital length 3-4 x orbit length. Nostrils thin and widely separated. Nasal curtain absent. Nasal flaps extend slightly over nostril opening.
Anterior margins of disc straight. Pectoral apices rounded. Dorsum covered in granular denticles. Ventral denticles much smaller and less distinct. Usually 3 orbital thorns. A row of large thorns present forward of each shoulder. Around 12 large thorns on midline from nape to first dorsal fin.
Tail fairly robust. Distance between dorsal fins greater than first dorsal in base length. Dorsal fins with tightly rounded apices and straight posterior margins. Caudal fin triangular, without a defined lower caudal lobe. Upper caudal tip acutely pointed.

Colour

Dorsum and fins beige or greyish-brown with many diffuse darker blotches that form thin bands across disc. Dark brown or black blotches on pectoral fins are filled with many small, yellow spots in adults. Rostral cartilage plain and much lighter than surrounding pigmentation. Ventrum mostly white with a pair of dark blotches near pectoral apices.

Size

Maximum length 78cm. Size at birth 18cm.

Habitat

Tropical/warm-temperate seas. On rocky reefs and sandy substrates. From very close inshore (observed resting in 3m) to 150m.

Distribution

Eastern Pacific. Found from central México to northern Peru.

Conservation Status

VULNERABLE

The Southern Banded Guitarfish (Zapteryx xyster) is captured in large-scale and small-scale shrimp trawl fisheries and in small-scale gillnet and longline fisheries. Fisheries operate without management throughout most of its range (or with inadequate enforcement of regulations) and the species has little refuge from fishing activities. It is either retained for local consumption or fishmeal or is discarded when caught. In Colombia, its abundance on shrimp trawl grounds is low; it is unknown if this reflects declines from previous abundance levels. Overall, given the intensity of fishing pressure throughout its range, it is suspected that the Southern Banded Guitarfish has undergone a population reduction of 30–49% over the last three generation lengths (21 years) due to levels of exploitation, and it is assessed as Vulnerable A2d.

Citation

Kyne, P.M., Charvet, P., Areano, E.M., Avalos, C., Cevallos, A., Espinoza, M., González, A., Herman, K., Mejía-Falla, P.A., Morales-Saldaña, J.M., Navia, A.F. & Velez-Zuazo, X. 2020. Zapteryx xysterThe IUCN Red List of Threatened Species 2020: e.T60178A124448370. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T60178A124448370.en. Accessed on 20 February 2022.

Reproduction

Aplacental viviparous. Litter size ~6.

Diet

Feeds at night mainly on small benthic fishes and prawns.

Behavior

Poorly known.

Reaction to divers

Very easy to approach. Usually remains motionless unless closely harassed.

Diving logistics

Southern banded guitarfish are relatively common at dive sites in Guanacaste, Costa Rica, during the colder months from December to March. In early January, they were particularly abundant on the shallow reef a few meters offshore at Playa El Jobo.

Similar species

Banded Guitarfish Distinguished by more rounded snout and plainer pattern without clusters of yellow spots.