Ammothella spinifera Cole, 1904

León-Espinosa, Angel De, León-Gonzalez, Jesus Angel De & Gómez-Gutiérrez, Jaime, 2021, Pycnogonids from marine docks located along the west coast of the Gulf of California, Mexico, Zootaxa 4938 (2), pp. 151-195 : 157-160

Ammothella spinifera Cole, 1904

( Figs. 2 A–F; Fig. 3 A–L)

Ammothella spinifera Cole, 1904: 275–277 , pl. 12, fig. 8, pl. 20, figs. 7–9, pl. 21, figs.1–6; Child, 1979: 11–12, fig. 3f–h; M̹ller, 1992: 33–34, figs. 2–3.

Material examined. 31 specimens: 3♀, 4³, 5J, (UANL-FCB-PYCNO-0055), FONATUR marine, Santa Rosalía , Baja California Sur, Mexico, 27°20´13´´N, - 112°15´47´´W, 01/11/2013 ; 3♀, 4³, 11J, (UANL-FCB-PYCNO-0056), same sampling location, 11/15/2013; 1³, (UANL-FCB-PYCNO-0057), La Paz marine, La Paz, Baja California Sur, Mexico, 24°09´17´´N, - 117°19´31´´W, 01/07/2013 ( Fig. 1 ) .

Description. The best-preserved specimen is a male with an oval-shaped body, fully segmented, glabrous except for a pair of dorsal setae inserted in the middle of segment two of the trunk, and two small tubercles on distal margin of cephalon and one on each lateral process, which are separated by about 0.3–0.4 of their own diameters ( Fig. 2 A ; Fig. 3 D ). Cephalon distally rounded. Ocular tubercle cylindrical, 2.8 times longer than wide, with four eyes, distal end as a small cone ( Fig. 2 A–B; Fig. 3 D, F ). Abdomen long, four times longer than wide, inserted at a 30° angle upward ( Fig. 2 B ), with two pairs of dorsal setae and some irregular lateral filaments ( Fig. 2 A–B; Fig. 3 L ). Proboscis oval, two times longer than wide ( Fig. 2 A–B), triangular mouth, lips lined with small setae ( Fig. 3 A–B).

Chelifore long, scape formed by two articles, first article small, ½ the size of the second, with a median-dorsal seta; second article with a proximal-dorsal seta, a pair of small setae inserted anteriorly, two pairs of lateral setae, and a series of long setae inserted distally. Chela rudimentary, ovoid ( Fig. 2 A–B; Fig. 3 C–E).

Palp with nine articles ( Fig. 2 C ; Fig. 3 E ). First article short, glabrous. Second article four times longer than the first one, with a row of four median-dorsal setae, followed by a long anterior seta and a median-ventral long seta. Third article 1.2 times longer than first one, glabrous. Fourth article longest, five times longer than the first one, armed with a row of three lateral and three ventral small setae, a pair of long dorsal setae, and a pair of long laterodistal setae. Fifth article two times longer than first one, with a row of four ventral setae and a row of four lateral setae, forming a “V” with the proximal vertex. The sixth article is twice as long as the first one, with a group of five ventro-distal setae. Seventh article 1.2 times longer than first one, with four ventral setae in a row. Eighth article pyriform, 1.2 times longer than the first one, with two long distal setae, one dorsal and one ventral. Ninth article 2.2 times longer than first one, distally covered by 8–9 longer setae.

Oviger with 10 articles ( Fig. 2 E–F; Fig. 3 J–K). First, third and fourth articles glabrous; second article with a dorso-anterior seta; fifth article with two dorso-anterior setae; sixth article with a basal seta and two pairs of lateral setae; seventh article triangular, with three anterior setae and three large lateral setae; eighth article with two anterior setae; articles nine and ten glabrous; terminal three oviger articles with denticulate spines, formula 1: 1: 2.

Legs of similar shape and length ( Fig. 2 D ; Fig. 3 G–I). Coxa 1 small, with five median-dorsal setae, the central one thicker than the lateral ones, a long dorso-distal seta and three median-ventral setae, the medial one is the longest. Coxa 2 almost as long as coxa 1 and 3 together, with a row of four short median-dorsal setae, a row of four short median-ventral setae and a longer distal one. Coxa 3 with a large median-dorsal seta and a group of four median-ventral setae. Femur longer than coxae 1 to 3 combined, with a row of six short median-dorsal setae followed by a large seta and a pair of anterior similar setae, two basal lateral setae, and a row of eight ventro-lateral setae. Femoral cement gland a long tube arising dorso-distally from a low tubercle, ¾ femur diameter ( Fig. 3 H ). Tibia 1 and 2 of the same size as the femur, both with numerous setae, dorsal setae larger than lateral and ventral ones. Tarsus small, subtriangular, with a dorsal seta inserted at the anterior end similar in length to the three ventral ones. Propodus with a row of eight large dorsal spines, a row of four medium setae in lateral view; heel with two thick basal spines followed by a row of six sole spines. Main claw strong, near 0.3 propodal length, slightly curved, auxiliary claws slender and slightly shorter than main claw length.

Female: Ammothella spinifera female bodies observed in the present work were considerably smaller than adult males; therefore, their ovigers have considerably shorter articles. Also, setae on coxae of females are shorter.

Measurements of the illustrated specimen (mm). Trunk length from the chelifore insertion to tip of fourth lateral processes, 0.9; trunk width across second lateral processes, 0.8; proboscis length, 0.8, 0.41 wide.

Third leg: coxa 1, 0.27; coxa 2, 0.49; coxa 3, 0.34; femur 0.73; tibia 1, 0.78; tibia 2, 0.82; tarsus, 0.07; propodus 0.56; claw 0.15.

Oviger: article 1), 0.1; 2), 0.5; 3), 0.36; 4) 0.56; 5) 0.49; 6) 0.14; 7) 0.07; 8) 0.07; 9) 0.07; 10) 0.03.

Distribution. Cole (1904) describes Ammothella spinifera from a specimen collected at San Diego, California, USA. Since then, A. spinifera has been observed sporadically. Child (1979) reported A. spinifera along the eastern Pacific in Mexico: Puerto Peñasco, Sonora; Mazatlán, Sinaloa; Bahía Petatlán and Guerrero; Gulf of Nicoya, Costa Rica; and Panama in the channel zone. In the Atlantic Ocean it has been recorded in the Caribbean of Panama in Galeta Island, Guanche Point, Portobelo Bay and Gulf of San Blas. M̹ller (1992) extends its distribution to Barbados Island, in the Caribbean Sea. This is the first report of A. spinifera from the western coast of the Gulf of California along Baja California Sur coast (about 440–455 km from the closest previous reports at Puerto Peñasco, Sonora and Mazatlán, Sinaloa).

Remarks. The genus Ammothella currently includes 42 nominal species world-wide. Only three species have been reported in Western Mexico: Ammothella marcusi Hedgpeth, 1948 for the Mexican Pacific, Ammothella spinifera Cole, 1904 for the Mexican Pacific and the Gulf of California and Ammothella symbia Child, 1979 for the Gulf of California.

Cole (1904) described A. spinifera on the basis of three specimens, two females and a juvenile. The holotype has a pair of long spines in the dorsal middle part of the posterior border of the first and second segments of the trunk. Child (1979) mentioned that the diagnostic character is the presence of one or two spines in the posterior margin of the second segment of the trunk, another consistent character is the presence of a spine in the anterior margin of the cephalic segment, almost always accompanied by a shorter spine. Ammothella spinifiera also has longer chelifores than the morphological similar species A. symbia . M̹ller (1992) mentioned that specimens of A. spinifera from Barbados do not possesses these spines. Twenty specimens (61%) of the 31 analyzed in the present study had two spines in the second segment, six specimens (20%) have one spine in the second segment, three specimens (10%) had two spines in the second segment and one spine in the third segment; two specimens (6%) with two spines in the first segment and two spines in the second segment and one specimen (3%) has a spine in the first segment. No consistent relationship of the number of spines and sex or developmental stage (juveniles and adults) was found in these specimens.

Figures

FIGURE 1. Area of study showing the nine marine docks located along the peninsular coast of the Gulf of California, Mexico. 1 = Cabo San Lucas; 2 = Puerto Los Cabos; 3 = FONATUR-Fidepaz; 4 = La Paz; 5 = Fiscal Pier, 6 = Palmira, 7 = Cantamar; 8 = Puerto Escondido (located about 50 km south of Loreto), and 9 = FONATUR-Santa Rosalía, Baja California Sur, Mexico. A magnification of the map shown marine docks 3–7 located at Bahía de La Paz.

FIGURE 2. Ammothella spinifera, UANL-FCB-PYCNO-0055, male: A, trunk, dorsal view; B, trunk, lateral view; C, palp, lateral view; D, third leg, lateral view; E, oviger; F, terminal articles of oviger. Scale bars A–B, E = 0.5 mm; C–D, F = 0.1 mm.

FIGURE 3. Ammothella spinifera, UANL-FCB-PYCNO-0056, male: A, proboscis, frontal view; B, anterior end, latero-dorsal view; C, anterior end, top view, showing chelifores; D, ocular tubercle, frontal view; E, chelifore and palp, lateral view; F, trunk, lateral view; G, third leg, lateral view; H, walking leg femur showing cement gland; I, tarsus, propodus and claws of leg 3; J, oviger; K, oviger, terminal articles; L, abdomen in frontal view. Scale bars: A, G, K = 1 mm; I = 0.5 mm; B, F, J = 0.3 mm; C–E, H, L = 0.2 mm.