Glyptoxanthus meandricus (Lockington, 1877)

(Figs. 8, 10 G)

Actaea meandrica Lockington, 1877: 97 (type locality: Mulegé Bay, Gulf of California, Mexico). Glyptoxanthus labyrinthicus, Rathbun 1930: 266 (in part). Not Actaea labyrinthica Stimpson, 1860. Glyptoxanthus felipensis Rathbun, 1933: 147 (type locality: San Felipe, Gulf of California, Mexico). — Crane 1937: 70, pl. 6

figs. 20, 21.

Glyptoxanthus meandricus, Glassell 1934: 301. — Garth, 1939 pl. 4 fig. 3, pl. 5 figs. 1c, 2c, 3c. — Guinot 1967: 556; 1971: 1072; 1979: 68, pl. 6 fig. 1. —Ng et al. 2008: 197 (list).

Material examined. Mexico: Neotype (here designated), male, 40.7 × 27.1 mm (LACM CR 1940.65), intertidal shingle, 0 m, 27º51.8’N 111º06.3’W, Bahia Catalina, off Guaymas, Sonora, coll. Velero III, 9 Feb. 1940.

Other material: 3 males, 25.8 × 17.5 mm —46.0 × 30.2 mm (LACM CR 1940.65), same data as neotype; 1 female, 33.9 × 23.0 mm (MNHN-B8362), Gulf of California, coll. Diquet, 1900, det. D. Guinot, 1976; 1 male, 24.9 × 16.7 mm (LACM CR 1500.024.1), Punta Peñasco, Sonora, coll. J. Littlepage, det. G. labyrinthicus by J.S. Garth.

Types of Glyptoxanthus felipensis Rathbun, 1933: holotype, female, 44.0 × 28.5 mm (USNM 67569); paratypes, 4 males, 16.9 × 11.3 —36.6 × 24.5 mm, 3 females, 22.6 × 15.4 mm —37.1 × 24.9 mm (USNM 67569), 1 male, 24.3 × 16.1 mm, 1 female, 30.3 × 21.2 mm, (LACM CR 19332085), San Felipe, Gulf of California, coll. H.N. Lowe, 6–15 May 1933.

Diagnosis. Carapace transversely ovate, width-to-length ratio about 1.5; regions more-or-less defined, some deeply punctate; intervening furrows narrow, setose; 2M completely divided longitudinally, inner branch fused with 1M; 3M completely independent of 2M; 4M abutting 3M, but separated from 1P by irregular furrow; 2L, 3L, 4L distinct, 5L and 6L fused, cervical furrow deep and wide at level of 6L and 4M; 1P anfractuous; 2P divided into smaller asperate lobules; vermiculations pronouncedly granular, narrow, convoluted. Front quadrilobate. Anterolateral margin arcuate, weakly divided into 4 lobes, none of which are distinct. Male thoracic sternum with reticulate pattern of narrow, granulate ridges, between shallow, granulate cavities. External surfaces of pereopods with similar sculpturing as carapace. Abdomen with parallel, transverse, granulate bars on external surface. G1 long and slender; terminal end bluntly tipped, studded with spinose granules; ventral margin of aperture with 2 short, simple setae; G2 about one-fourth length of G1.

Remarks. Lockington (1877) described Actaea meandrica from the Gulf of California, but did not provide any illustration. This species was not included when A. Milne-Edwards (1879) established the genus Glyptoxanthus, and in fact, there was no further mention of it until 1930. Rathbun (1930) included this species in the synonymy of Glyptoxanthus labyrinthicus (Stimpson, 1860), without having examined any specimen as, according to her, the types were no longer extant. She later described a new species, Glyptoxanthus felipensis Rathbun, 1933, also from the Gulf of California. Glassell (1934), however, considered G. meandricus (Lockington) as distinct from G. l a b y - rinthicus (Stimpson), and this view was also supported by Garth (1939). Furthermore, Guinot (1967, 1979) considered G. felipensis as a junior synonym of G. meandricus (Lockington). Ng et al. (2008) correctly listed G. felipensis as a junior synonym of G. meandricus, but attributed the latter name to the wrong author, Klunzinger, having confused it with another species, G. meandrinus (Klunzinger, 1913), from the Red Sea. To stabilize the taxonomy of this species, a neotype male (40.7 × 27.1 mm), collected from the Gulf of California and deposited at the Natural History Museum of LA County, in Los Angeles, USA (LACM CR 1940.65), is hereby designated in accordance with Article 75 of the Code. This action is necessary to provide a definite name-bearing type on which to base future comparisons, as the original description of this species by Lockington is rather vague; and also to distinguish it from other species of Glyptoxanthus occurring in the eastern Pacific, although this is the only species known to occur in the Gulf of California.

Glyptoxanthus meandricus is easily distinguished by the narrow and strongly granulate vermiculations on its carapace (and pereopods), which are separated by correspondingly narrow furrows; the independent 3M and the completely divided 2M regions; the poorly produced lobes on the carapace anterolateral margins; and the reticulate pattern of narrow ridges and shallow cavities, both of which are granulate, on the thoracic sternum.

Some of the preserved specimens we have examined had a uniform, dark reddish-brown colouration, and had the furrows on the exposed surfaces filled with mud.

Ecology and geographical distribution. Glyptoxanthus meandricus has only been found, thus far, in the Gulf of California, presumably from the intertidal to the shallow subtidal zones amidst rocky substrate.