Friday, July 31, 2020

[Ichthyology • 2020] Vanderhorstia vandersteene • A New Species of Shrimpgoby (Pisces: Gobiidae) from Papua New Guinea


Vanderhorstia vandersteene
 Allen, Erdmann & Brooks, 2020


Abstract
A new species of gobiid fish, Vanderhorstia vandersteene, is described from the East Cape region of Milne Bay Province, Papua New Guinea on the basis of five specimens 17.5-32.2 mm SL. Diagnostic features include dorsal-fin elements VI-I,10-12; the fourth dorsal-fin spine filamentous, reaching the base of about the fifth to seventh segmented dorsal-fin ray when adpressed; anal-fin rays I,11; pectoral-fin rays 16-18; lateral scales 35-37; transverse scales 10; body scales mostly ctenoid, except cycloid scales anterior to the level of about the second-dorsal-fin origin, as well as on the pectoral-fin base, prepelvic region, and the lower side between the pectoral-fins and pelvic fins; scales absent on the head, including medially and anteriorly on the predorsal region; the caudal fin lanceolate with an elongate, median filament; color in life light neon blue with a wavy yellow-orange stripe from the upper operculum to the upper caudal-fin base, prominent yellow-orange bars, bands, and spots on the head and upper sides, a pair of yellow stripes on the second dorsal fin, and yellow streaks and bands on the caudal fin. We include a key to the Vanderhorstia species with low lateral-scale counts (less than 45).


Vanderhorstia vandersteene, freshly collected paratype, female, 27.2 mm SL, East Cape region, Milne Bay Province, Papua New Guinea (Mark V. Erdmann). 

Vanderhorstia vandersteene, live holotype, male, 32.2 mm SL, East Cape region, Milne Bay Province, Papua New Guinea (Mark V. Erdmann).

Vanderhorstia vandersteene, live paratype, female, 27.2 mm SL, East Cape region, Milne Bay Province, Papua New Guinea (Mark V. Erdmann). 

Vanderhorstia vandersteene
, n. sp. 
Electric Shrimpgoby

Diagnosis. Dorsal-fin elements VI-I,10–12, fourth dorsal-fin spine filamentous, reaching base of about fifth to seventh segmented dorsal-fin ray when adpressed; anal-fin elements I,11; pectoral-fin rays 16–18; lateral scales 35–37; transverse scales 10; body scales mostly ctenoid, except cycloid scales anterior to level of about second dorsal-fin origin, on pectoral-fin base, prepelvic region, and lower side between pectoral and pelvic fins; scales absent on head, including medially and anteriorly on predorsal region; caudal fin lanceolate with an elongate median filament; color in life light neon blue with wavy yellow-orange stripe from upper operculum to upper caudal-fin base; prominent yellow-orange bars, bands, and spots on head and upper sides; a pair of yellow stripes on second dorsal fin and yellow streaks and bands on caudal fin.


Etymology. The new species is named vandersteene, which is treated as a noun in apposition for the combined surnames of Rob Vanderloos and Roger Steene, two highly esteemed underwater photographers who have contributed greatly to our knowledge of the reef fishes of Milne Bay and who have been loyal diving companions over the course of three decades of exploration of the region. It is a pleasure to name this stunning new species in their honor.

Distribution and habitat. The new species is currently known only from the type locality, situated on the East Cape Peninsula of Milne Bay Province, Papua New Guinea, about 28 km northeast of the town of Alotau. The habitat consists of a relatively steep outer reef slope with fish occupying burrows on black volcanic sand/ rubble substrates. About 20 individuals were observed in an area that occupied about 600 m2 . Solitary individuals were encountered that were invariably associated with an unidentified snapping shrimp of the genus Alpheus that share the burrows, a symbiotic relationship found in all Vanderhorstia spp.


Gerald R. Allen, Mark V. Erdmann and William M. Brooks. 2020. Vanderhorstia vandersteene, A New Species of Shrimpgoby (Pisces: Gobiidae) from Papua New Guinea. Journal of the Ocean Science Foundation. 35, 65-75. DOI: 10.5281/zenodo.3959464