Morphological comparison between Doryteuthis pleii and D. sanpaulensis (Cephalopoda, Myopsida, Loliginidae) from Brazil

Abstract

The distinction of squid species in the genus Doryteuthis is not easy due to their morphological similarity, lack of conspicuous specific characters, and overlap geographical occurrence. This difficulty has leading to an almost exclusive molecular approach, and a premature neglect of the morpho-anatomy. To emphasize that the squid phenotypic features can be useful to identify, as well as to perform any comparative analyses (such as taxonomy and phylogeny), two close species were selected as outset. Doryteuthis pleii and D. sanpaulensis are common sympatric squids in Brazilian waters, commonly used in fisheries, not so difficult to distinguish by external features of the adult specimens. The samples were analyzed from biometric data to dissections, and the found most expressive characters to distinguish them are the mantle-fin ratio; morphology of the tentacle club, its ratio compared to the mantle length; hectocotylus morphology and nidamental gland morphology.

Feeding habits of South American and sub‐Antarctic fur seals during their nonbreeding season in the southwestern Atlantic Ocean

“…Frequency of Occurrence (%FO) of the main prey consumed by South American fur seals (SAFS, Arctocephalus australis ) the southern Brazilian coast, as determined by stomach content analysis for two distinct periods: Period I (1980–1992) and Period II (2007–2021). Prey illustrations were sourced from Fischer et al (2011) and Migliavacca & Simone (2020). …”

Loliginid paralarvae from the Southeastern Gulf of Mexico: Abundance, distribution, and genetic structure

“…Eyes not large; diameter of the externally visible eyeball 14%-19% ML, diameter of dissected lens 2%-7% ML. Left ventral arm hectocotylized in mature males by a modification of distal half to a fourth of arm that extends to arm tip; one-half to three-fourths (42-82) of suckers in a dorsal row much smaller than half the size of their ventral counterparts; modified (small) suckers on small, narrow, triangular pedicels (Figure 2G) (Hanlon et al, 1992;Vecchione & Young, 2010;Dıáz-Santana-Iturrios et al, 2019;Migkuavacca and Simone, 2020).…”

Review of Fishery Oceanography of the Early Stages of Loliginidae (Cephalopods: Myopsida): Paralarvae along the Continental Southeast Platform of Brazil between the Cape of São Tomé (Rio de Janeiro) and Cananeia (São Paulo) (22º-25ºS)

“…Among the representations of Loliginid squids, typically neritic, (Doryteuthis plei and Doryteuthis sanpaulensis formerly known as Loligo) is relatively more abundant in the southern region of Brazil (Haimovici & Perez, 1991;Haimovici & Andriguetto, 1986;Andriguetto & Haimovici, 1991;Costa & Fernandes, 1993a), as well as in northern Argentina 35 °S (Castellanos, 1967;Costa, 1994), sustaining a significant volume of catches (Costa & Haimavici, 1990;Perez, 2002;Gasalla et al, 2005), Cape Hatteras (36 ° N) which is usually associated with the Brazilian hot current. It also includes the Gulf of Mexico as the dominant nectonic invertebrate species during some seasons (Dragovich & Kelly, 1967;Livingston et al, 1976), the Caribbean Sea, Bermuda and the islands of the Bahamas and the Caribbean (Migliavacca et al, 2020). The increase in catches may be a natural consequence of the decline in traditional fishing resources, which leads to increased availability and effort for capturing the potential of non-traditional species (Rodhouse, 2005).…”