Chaetopleura lurida (G. B. Sowerby I, 1832)

Reyes-Gómez, Adriana, Flores-Garza, Rafael, Galeana-Rebolledo, Lizeth, Hernández-Vera, Gerardo, Galván-Villa, Cristian M., Torreblanca-Ramírez, Carmina, Flores-Rodríguez, Pedro, García-Ibañez, Sergio & Ríos-Jara, Eduardo, 2022, Intertidal chitons (Mollusca: Polyplacophora) from the rocky coastline of Guerrero, México, with the description of a new species, Zootaxa 5155 (4), pp. 451-492 : 456

Chaetopleura lurida (G. B. Sowerby I, 1832)

Figures 2A , 3A–J , 4A–C

Distribution. Continuously distributed from Bahía de San Francisquito Baja California; Isla Socorro and Clarión, Revillagigedo, México to northern Colombia, including Gorgona Island ( Kaas & Van Belle 1987).

Type specimens. According to Kaas & Van Belle (1987), syntype BMNH 1982006 .

Type Locality. Santa Elena , West Colombia.

Material examined. 142 specimens; maximum size 30.9 mm length, 18.2 mm wide. N (n=22); D (n=8); T (n=4); U (n=15); M (n=11); L (n=4); P (n=7); K (n=4); A (n=10), B (n=10); R (n=6); E (n=12); H (n=5); G (n=7); F (n=9); J (n=8); I (n=10).

Habitat and bathymetric range. This species can be found in a variety of habitats. Commonly adult animals (20–30 mm) occur in the shallow subtidal to 7 m depth and on the underside of rocks buried in sand or covered with red and brown crustose algae. Juvenile specimens were usually found in the subtidal (5–10 m depth) on shells or small stones, rarely on larger rocks. Adults are usually covered with bryozoans, polychaetes, and green or red algae that can also be attached to the girdle. Chaetopleura lurida was found together with Chiton albolineatus , C. articulatus , Tonicia forbesii , and Stenoplax limaciformis .

Remarks. Chaetopleura lurida differs from C. hanselmani by the shape of the pustules, which are somewhat cylindrical, and by having the double number of pustules. The maximum length recorded for C. lurida is 30.9 mm, while C. hanselmani can attain up to 11.8 mm.

The sculpturing pattern for this species has been reported to be highly variable ( Ferreira 1983a; Kaas & Van Belle 1987); regarding their observations, we also found morphologic distinctions in the sculpturing arrangement and color. The examination of 31 specimens from Baja California Sur (e.g., specimen CNMO 1004 from Isla Partida; Fig. 20I ) exhibited in general (from 26 examined chitons) pustules aligned more symmetrically in the lateral areas of intermediate valves, than the specimens from Guerrero and Oaxaca (southern México) that are irregularly scattered nearest the valve´s midline. Regarding the density of pustules, we observed that the chitons (29 specimens) from Sayulita, Nayarit (e.g., CNMO 4651, Fig 20J ) showed a higher number of pustule rows in the lateral areas (5–7) than those from Guerrero and Oaxaca (3–5). We also identified a latitudinal pattern of color variation: Oaxaca specimens (e.g., CNMO 5813, Fig. 20G ) were usually brown, gray, or occasionally pink, while Guerrero specimens were similar but had more areas with olive green coloration, whereas Mazatlán and Baja California Sur specimens usually had reddish-brown tones with dark zebra-like lines in the lateral areas.

Figures

FIGURE 2. Dorsal view of the whole specimens that represent the analyzed species. A, Chaetopleura lurida, BL 27.48 x 15.70 mm, Majahua, Acapulco (CNMO 5229). B, Chaetopleura hanselmani, BL 11.02 x 7.16 mm, Tlacopanocha, Acapulco (CNMO 5804). Ischnochiton muscarius, C, BL 16.62 x 9.77 mm, Angosta, Acapulco (CNMO 5202); D, BL 15.12 x 9.55 mm, Barra de Potosí Protegida, Petatlán (CNMO 5338); E, BL 18.30 x 10.17 mm, Troncones, La Unión (CNMO 5327); F, BL 14.98 x 9.51 mm, La Barrita, Petatlán (CNMO 5315). G, Callistochiton elenensis, BL 12.32 x 7.76 mm, La Barrita, Petatlán (CNMO 5823). H, Callistoplax retusa, BL 20.41 x 9.68 mm, Parque de la Reina, Acapulco (CNMO 5185). Stenoplax limaciformis, I, BL 17.56 x 7.21 mm, Parque de la Reina, Acapulco (CNMO 5179); J, BL 20.12 x 9.15 mm, Tlacopanocha, Acapulco (CNMO 5208); K, BL 17.65 x 8.29 mm, Las Gatas, Zihuatanejo de Azueta (CNMO 5254); L, BL 19.78 x 9.84 mm, Isla Grande, Zihuatanejo de Azueta (UAGRO 0024). Chiton albolineatus, M, BL 23.84 x 14.63 mm, Piedra de Tlacoyunque, Tecpan de Galeana (CNMO 5337). Tonicia forbesii, BL 33.41 x 17.86 mm, Isla Grande, Zihuatanejo de Azueta (CNMO 5255). Acanthochitona arragonites, O, BL 8.80 x 5.2 mm, Las Salinas, Copala (CNMO 5267). Lepidochitona salvadorensis, P, BL 10.63 x 5.7 mm, Barra de Potosi Protegida, Zihuatanejo de Azueta (CNMO 5332).

FIGURE 3. Chaetopleura lurida, disarticulated valves of a specimen BL 20.31; valves in dorsal view A, head valve; B, intermediate valve IV; C, tail valve. Valves in ventral view, D, head valve; E, intermediate valve IV; F, tail valve. SEM images of a specimen BL 15.9 mm length. Valves in dorsal view; G, head valve; H, intermediate valve IV, I, tail valve. J, intermediate valve IV in ventral view.

FIGURE 4. Chaetopleura lurida, SEM images of a specimen BL 15.9 mm, A, girdle corneous hairs; B, girdle spicules; C, radular teeth. Chaetopleura hanselmani, BL 10.11 mm; valves in dorsal view, D, head valve; E, intermediate valve IV. Valves in ventral view, F, head valve; G, intermediate valve IV. SEM images of a specimen BL 10.9 mm; valves in dorsal view, H, head valve; I, intermediate valve IV; K, tail valve. J, valve IV in ventral view.

FIGURE 20. Chiton articulatus, specimen BL 27 mm, El Faro, Mazatlán (CNMO 5661); shows the tegmentum color details A, head valve; B, intermediate valves III-V; C, tail valve. Specimen BL 24.45 mm, Santa Elena, Oaxaca (CNMO 1066); shows color tegmentum details; D, head valve; E, detail of intermediate valves III-V; F, tail valve. Chaetopleura lurida, G, dorsal view of whole specimen BL 21.3 x 13.7 mm, Estacahuite, Oaxaca (CNMO 5813). Chaetopleura lurida, specimen of 27.9 x 15.4 mm, dorsal view of valve I and IV, Isla Partida, Baja California Sur (CNMO 1004), H, head valve and I, valve IV; J, whole specimen BL 25.8 mm, Sayulita, Nayarit; K, Ischnochiton muscarius, whole specimen BL 27.6 mm in dorsal view.Callistochiton elenensis, L, whole specimen BL 19.46 mm, La Paz, Baja California Sur (UAGRO 0060); M, detail of sculpturing of valves II-IV; N, Chiton articulatus, N, whole specimen in dorsal view, BL 37.2 mm, Sayulita, Nayarit (CNMO 40012).