Background

The presence of Thysanoteuthis rhombus Troschel, 1857 in the eastern Pacific Ocean was estimated based on the geographic range of the species constructed from scattered locations of adults, juveniles, and egg masses.

Goals

This note describes morphometric characteristics of the southernmost registry of the diamond squid T. rhombus in Mexican waters of the Gulf of Tehuantepec (16°N-95°W).

Methods

In January 2015 we found a stranded adult female weighing a total of 12.5 kg, with a total length of 92 cm, and a mantle length of 45.5 cm.

Results

This was a mature female, with oocytes inside the oviducts that averaged 1.2 mm in diameter, and seven attached spermatophores on the buccal membrane of the female, as evidence of mating.

Conclusions

This late registry in the Gulf of Tehuantepec could simply be due to their relative scarcity in the eastern Pacific Ocean.