Marine & Environmental Sciences Faculty Articles
Document Type
Article
Publication Date
5-10-2023
Publication Title
Frontiers in Marine Science
Keywords
Stomiidae, Melanostomiinae, trophic ecology, ecomorphology, morphological-dietary relationships, mesopelagic
ISSN
2296-7745
Volume
10
First Page
1056094
Abstract
Two of the main drivers of speciation among aquatic vertebrates are physical isolation (e.g., lakes and streams) and micro-niche availability (e.g., tropical reefs). In both regards, the mesopelagic domain of the open ocean, Earth’s second largest cumulative ecosystem (behind only the bathypelagic domain), would seem retardant. Ocean circulation makes isolation rare on both contemporary and geological time/space scales, and the lack of substrate precludes stable micro-niches. Paradoxically, some pelagic taxa demonstrate much higher-than-expected species richness on regional scales. A prime example is the dragonfish family Stomiidae, the most speciose family of mesopelagic fishes, owing largely to the subfamily Melanostomiinae (scaleless black dragonfishes), which contributes 222 of the 320 described species. Within genera, species are differentiated almost solely by form of the jugular-positioned, bioluminescent barbel, a structure putatively linked to feeding (via prey luring). The relationship between diversity (both systematic and morphological) and diet within the Melanostomiinae has not been previously examined, primarily due to sample size limitation. Herein, the diet and morphology of 16 species of melanostomiine dragonfishes from the Gulf of Mexico were examined to ascertain whether the diversification in this fish clade is based on prey specialization, as is the case with many other speciose fish families (e.g., Cichlidae). Gut content analysis revealed a rather small spectrum of prey taxa across a wide spectrum of predators, with most species exhibiting piscivory centered on the most regionally abundant lanternfishes (Myctophidae). Lesser numbers of species preyed upon bristlemouths (Gonostomatidae), oceanic basslets (Howellidae), bigscales (Melamphaidae), and other dragonfishes, while three species selected for cephalopod prey. No dragonfish species consumed macrocrustaceans (e.g., decapod shrimps), despite their numerical prevalence as potential prey. Regarding functional morphology, dissimilarity was driven mostly by barbel length, vertical oral gape, and horizontal maxillary oral gape. There were no robust morphological-dietary relationships amongst melanostomiines, with dietary diversity much lower than morphological diversity. These results suggest that other factors, perhaps conspecific recognition and/or sexual selection related to spawning, may be primary drivers of hyperspeciation in the micro-habitat-poor pelagic environment.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
NSUWorks Citation
Ryan P. McGonagle, David Kerstetter, Danté Fenolio, and Tracey Sutton. 2023. Ecomorphology of a Predatory Deep-sea Fish Family: Does Trophic Specialization Drive Hyperspeciation? .Frontiers in Marine Science : 1056094 . https://nsuworks.nova.edu/occ_facarticles/1345.
ORCID ID
https://orcid.org/0000-0002-5280-7071, https://orcid.org/0000-0002-4440-8767
DOI
https://doi.org/10.3389/fmars.2023.1056094
Comments
© 2023 McGonagle, Kerstetter, Fenolio and Sutton. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.