Spelaeomysis quinterensis ( Villalobos, 1951 )

Pesce, Giuseppe L. & Iliffe, Thomas M., 2002, New records of cave-dwelling mysids from the Bahamas and Mexico with description of Palaumysis bahamensis n. sp. (Crustacea: Mysidacea), Journal of Natural History 36 (3), pp. 265-278 : 266-268

Spelaeomysis quinterensis ( Villalobos, 1951)

(figures 1- 4)

Material examined. Tamaulipas, Mexico: cave spring on the Rio Guayalejo near Juamave; 15 March 1998; one mature female (length 7.5 mm) collected with vial from water column in 10 m depth by T. M. Iliffe .

Taxonomic notes. The single specimen we examined from a cave spring on the Rio Guayalejo is identical to S. quinterensis described and illustrated by Villalobos (1951) from the type-locality (Quintero cave, Tamaulipas, Mexico), as well as by Bowman (1973, 1982) and Reddell (1981), also from Mexico, differing only by the following minor characteristics:

(1) Antennal scale more rounded and slightly wider as compared to Villalobos’ description and figures; antennal fl agellum with more and longer segments (fi gure 2).

(2) Sixteen to 18 long spines on the medial lobe of uropod (fi gure 4) (vs 20 or more, and shorter spines both in Villalobos’ and Bowman’s figures).

(3) Telson armed with 33 spines (fi gure 1) (vs 25 and 27 spines in Villalobos’ and Bowman’s figures, respectively); moreover in the specimen from Guayalejo spring, the medial apical spine is fl anked by two slender plumose setae (vs the same spines fi gured as naked in the original and following descriptions and figures). However, in this last regard, we suppose that the re-examination of typical material could reveal the presence of the same plumose setae also in S. quinterensis , since these setae have been reported and fi gured in other species of the genus ( S. bottazzi , S. longipes ) and probably they could be present, but overlooked, also in the remaining ones.

(4) Pleopod 2 (fi gure 3) slightly shorter and less setulose as compared to Villalobos’ figures.

The peculiar telson armature could justify recognition of the Guayalejo spring specimen as a distinct species or subspecies, but until enough material from this locality, as well as from the type-locality, becomes available to assess adequately the variability of S. quinterensis , we consider the Guayalejo spring and the Villalobos’ material to be conspeci fi c.

Habitat. This spring is located on the south bank of the Rio Guayalejo as it passes through a large canyon crossing the Sierra Madre Oriental. The spring pool is located about 50 m inland from the river bank and consists of a shallow basin about 5 m in diameter, beneath a rock ledge. Underwater, a cave trends away from the river for about 100 m before coming back to the surface in a small air- fi lled chamber with possible dry cave passages leading off. Maximum depth in the underwater cave was 15 m. The stygobitic cirolanid Speocirolana disparicorni s Botosaneanu and Iliffe, 1999 and the amphipod Seborgia near hershleri (det. J. R. Holsinger, 13 April 1999) were also collected from the cave.

Remarks. The genus Spelaeomysis presently includes nine named species, seven from various groundwater habitats (anchialine caves, springs and wells) in south Italy, Zanzibar, Mexico and Cuba, one from prawn culture fi elds in India, and another one from crab burrows in Colombia. Recently, Garc1´a-Garza et al. (1996) presented a key to the known species in the genus, including only seven species and omitting S. bottazzii Caroli, 1924 and S. cochinensis Panampunnayil and Viswakumar, 1991 . Moreover, in the same paper, the authors misspelled the name of S. servatus with S. serratus .

Three species are presently known from subterranean waters in Mexico: Spelaeomysis quinterensis ( Villalobos, 1951) [cave waters, Tamaulipas] Spelaeomysis olivae Bowman, 1973 [cave waters, Oaxaca] Spelaeomysis villalobosi Garc1´a-Garza, Rodriguez-Almaraz and Bowman, 1996 [phreatic and cave waters, Nuevo León]

The remaining species come from the following localities: Spelaeomysis bottazzii Caroli, 1924 [anchialine cave and phreatic waters; south Italy] Spelaeomysis servatus (Fage, 1924) [cave waters; Kenya, Zanzibar, Aldabra] Spelaeomysis longipes (Pillai and Mariamma, 1963) [phreatic waters, India] Spelaeomysis nuniezi Bacescu and Orghidan, 1971 [cave waters, Cuba] Spelaeomysis cardisomae Bowman, 1973 [cave waters, crab burrows; Columbia, San Andres] Spelaeomysis cochinensis Panampunnayil and Viswakumar, 1991 [prawn culture fi eld; India]

Key to the species of the genus Spelaeomysis

1 Eyestalks with few disto-lateral ommatidia............ 2

- Eyestalks without ommatidia................ 4

2 Telson more than twice longer than wide......... S. cochinensis

- Telson less than 1.5 longer than wide............. 3

3 Apical spine of telson about twice length of two fl anking spines... S. servatus

- Apical spine of telson more than six times length of two fl anking spines. S. cardisomae

4 Eyestalks medially fused forming a single plate........ S. longipes

- Eyestalks separate.................. 5

5 Eyestalks produced anterolaterally into subtriangular lobes....... 6

- Eyestalks subquadrangular, not produced anterolaterally........ 7

6 Pleopod 4 with four-segmented exopod; telson slightly longer than wide; lateral margin slightly concave near midlength........... S. quinterensis

- Pleopod 4 with two-segmented exopod; telson about as long as wide, lateral margin convex................... S. villalobosi

7 Telson, margin of distal half armed with spines........... 8

- Telson, margin completely armed with spines........ S. bottazzii

8 Telson L/ W 1.5, with about 20 marginal spines......... S. nuniezi

- Telson L/ W 1.1 -1.2, with about 40 marginal spines........ S. olivae