Description: Specimens and data suggest that larval short-finned squid, Illex illecebrosus, may concentrate in water where density is approximately 26.7, indicating that spawning occurs in the subsurface interface where Slope Water mixes with the Gulf Stream. Because these water masses occur year-round within the range of I. illecebrosus, spawning may be a prolonged or progressive process along the shareward edge of the Gulf Stream. The distribution of other species indicates mesoscale spatial separation of young cephalopods in the vicinity of the Gulf Stream.

Description: The larval development of lllex is described and figured with particular attention to development of the tentacles and the fourth pair of arms. The larvae can be identified by the presence of relatively short fused tentacles which have 8 suckers of uniform size. By the time the tentacles separate they have developed 8 rows of sucker buds in the dactylus. Growth of the tentacles appears to occur at the base as well as the distal tip and the fused area separates rapidly at about 8.50 mm dorsal mantle length. Larval lllex collected primarily in subsurface samples from boreal waters along the outer Continental Shelf of the Middle Atlantic Bight in February and March 1977 are considered to be I. illecebrosus. lllex sp. larvae were also taken in subsurface samples from tropical waters in the mid-shelf region of the Middle Atlantic Bight during August 1977 and in surface samples over the Hatteras Abyssal Plain in February and March 1978.

Description: The Neocoleoidea, sister group to the Belemnoidea, includes all living cephalopod species except nautilids, as well as their immediate ancestors. Several hypotheses have been published about the morphology of ancestral neocoleoids. Ancestral states are easily infe1red from fossils for some characters, such as 10 arms and the presence of an ink sac in basal coleoids or the presence of fins in ancient octopods. Many inferences are less strongly supported, though, and open to debate. We examine this problem using three cladograms resulting from analyses of morphology and DNA sequences (both mitochondrial and nuclear) from samples representing the full diversity of extant coleoids. Character states at three ancestral nodes (neocoleoid, octopodiform, and decapodiform) are reconstructed for 51 morphological characters using cladistic parsimony. Strong or moderate agreement among the three trees was found for almost 3/4 of the character-at-node reconstructions. The level of agreement among the trees varied among nodes, with strongest agreement found at the ancestral octopodiform node. However, some of these reconstructions seem unlikely to be co1rect. Changes in subclade resolution can exert varying effects on inferences about basal nodes. Because several subclades within the neocoleoids are not yet adequately resolved, we cannot be very confident in reconstructions of ancestral character states based solely on parsimony and we propose a provisional suite of character-state reconstructions including other sources of inference in addition to parsimony.

Description: A behaviour that has never been seen in cephalopods was observed thre times in large aggregation of Brachioteuthis beanii Verrill, 1881. During a series of submersible dives off Cape Hatteras, North Carolina, estern U.S., three pairs of Brachioteuthis were seen, and one pair was video-taped. In all three pairs one squid grasped the other by the posterior mantle in its arm crown. This paired behaviour involved brief periods in which the grasped squid bent its head and body posteriorly and vigorously moved its arms around the head and mantle opening of the grasping squid. Although we were unable to capture any of the coupling pairs to determine their stage of maturity, we believe this unusual activity represents mating behaviour.

Description: The ecological role of large thecosome pteropods in the pelagic ecosystem of the northern Gulf of Mexico (GoM) may be substantial, both in the food web and biogeochemical cycling. We analyzed species abundances, vertical and horizontal distributions of large species with calcareous shells (those collected in 3-mm mesh nets). Pteropod samples were collected following the 2010 Deepwater Horizon oil (DWH) spill by two midwater sampling programs: the Offshore Nekton Sampling and Analysis Program (ONSAP 2011) and the Deep Pelagic Nekton Dynamics of the Gulf of Mexico (DEEPEND 2015) projects. All samples were collected using a 10-m2 Multiple Opening/Closing Net and Environmental Sensing System (MOC10) midwater trawl, with 3-mm mesh. This gear sampled five discrete depths between 0–1500 m. Over 13,000 pteropod specimens were examined, with 25 species identified. Clio pyramidata Linnaeus 1767 was the most abundant species during both collection periods. Five genera (Diacria, Clio, Styliola, Cuvierina, Cavolinia) demonstrated diel vertical migration from the mesoto epipelagic zone.