Meningodora compsa ( Chace, 1940 )

Meningodora compsa ( Chace, 1940)

( Figs. 17 View FIGURE 17 A–B, 18 View FIGURE 18 , 40 View FIGURE 40 B)

Notostomus compsus Chace, 1940:156 , Figs 31 View FIGURE 31 , 32a– i. Meningodora compsa — Crosnier & Forest 1973: 48, fig. 10e.— Kikuchi 1985:196 (key).— Chace 1986: 49 (key).— Kikuchi 1991: 25, fig. 2.

Material examined: 1 OF, off Pernambuco, Abracos 2, ST#16, Leg.1, Midwater Tow, 680 m, 07° 36,25’ S / 033° 99,17 ‘ W, 14 April 2017, MOUFPE: 18.354.

Diagnosis: Carapace dorsally sharply carinate for nearly its entire length. Rostrum with 5–6 dorsal teeth; 2–3 of them behind the anterior portion of orbit; rostrum without spine on ventral margin. Rostrum reaching beyond the antennular peduncles. Branchiostegal spine supported by a short carina. First somite of abdomen rounded dorsally; second somite with a very faint carina; third somite unarmed; fourth, fifth and sixth somites with a median posterior spine, sixth somite 2.2x longer than fifth. Telson shorter than uropods, deeply sulcate dorsally, with 4–5 pairs of dorsolateral spines.

Distribution: Western Atlantic: Bermuda. Southwestern Atlantic Brazil: (Pernambuco). Eastern Atlantic: Northern mid-Atlantic Ridge, Portugal (Azores Island), Senegal ( Chace 1940; Crosnier & Forest 1973) ( Fig. 18 View FIGURE 18 ).

Bathymetric distribution: 874–1829 m depth ( Chace 1940; Crosnier & Forest 1973), herein this species was found in Brazilian waters at depth of 680 m, thus extending its bathymetric distribution from shallower waters.

Remarks: The specimens analyzed herein do not differ from the descriptions of Chace (1940) and Crosnier & Forest (1973). According to Chace (1940) M. compsa might easily be confused with species of M. vesca ( Smith, 1886) , but can be distinguished by some differences as: in M. compsa , the total length of individuals vary between 11–16 cm; rostrum presents 4–5 dorsal teeth, ventral tooth absent; branchiostegal spine with a sharp ridge ( Fig. 17B View FIGURE 17 ) and sixth abdominal somite little longer than fifth, while in M. vesca the total sizes vary between 2–6 cm; rostrum presents 6–12 dorsal teeth and 1–2 ventral teeth; branchiostegal spine with reduced ridge (see Fig. 23 View FIGURE 23 ) and sixth abdominal somite almost twice longer than fifth. This species is known only from the Atlantic Ocean and it is rarely recorded above 500 m depth (bathypelagic distribution). The genus Meningodora currently comprises six species, with worldwide distribution in mesopelagic zones. Thus, this paper reports for the first time the occurrence of M. compsa from Southwestern Atlantic (Brazilian waters).