Collaborators: John Sparks (AMNH), Peter Wainwright (UC Davis), Leo Smith (U. Kansas) & Matt Davis (St. Cloud U.)

idiacanthus C
Figure 1. Idiacanthus sp. captured in the San Diego Trough.

Stomiiforms are an order of deep-sea fishes that include the dragonfishes (e.g., Fig. 1), hatchetfishes, lightfishes, and bristlemouths. Most species are light-producing (Fig. 2), and have diets varying from small planktonic invertebrates to other fishes. With the help of two high school interns under the American Museum of Natural History’s Science Research Mentoring Program (SRMP), I sought to characterize oral jaw diversity in this group.

Figure 2. Ventral light organs on a specimen of Argyropelecus.

For this work, we cleared and stained representatives from 42 of 53 genera within the order and used geometric morphometrics to evaluate shape variation of the feeding apparatus. We found that, excluding the morphologically distinct hatchetfishes (family Sternoptychidae), stomiiform jaw diversity follows a morphological trajectory characterized by variation in the relative length and angle of the jaw (Fig. 3). Future work will address whether the observed trend is correlated with the evolution of vertebral adaptations that allow for cranial rotation and increased oral jaw kinesis.

stomiiform jaws
Figure 3. Morphological trend in the stomiiform feeding apparatus, including covariation of jaw length and suspensorial angle.


Funding Sources:

Science Research Mentoring Program, SRMP (AMNH)