Anoplodactylus erectus 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 : 184-187

Anoplodactylus erectus Cole, 1904

( Figs . 19 A–G; 20 A–M )

Anoplodactylus erectus Cole, 1904: 289–291 , pl. 12 fig. 12, pl. 26 figs. 1–9; Hilton, 1916: 25, figs. 1–6; Child, 1970: 288; 1979: 52; M̹ller, 1989: 126, figs. 41–44; Nakamura & Child, 1991: 25.

Material examined. 16 specimens: 6♀, 9³, 1J, (UANL-FCB-PYCNO-0081), Fiscal dock, Bahía de La Paz, Baja California Sur, 24°09´41´´N, - 110°19´09´´W, 06/26/2017 ( Fig. 1 ) .

Description. Trunk cylindrical, thin, decreasing in diameter towards the back, completely segmented ( Fig. 19 A ). Lateral processes each with a tubercle on the dorso-distal part. All separated by less than ½ their own diameters ( Fig. 19 A ; Fig. 20 A ). Conical ocular tubercle, with three projections in the shape of papillae on top ( Fig. 20 E ), located in the anterior part of the cephalic segment, with two anterior and two posterior eyes ( Fig. 19 A ). Abdomen with an inclination of 50°, inserted between the last pair of lateral processes, with three lateral spines, one middle and two distal ( Fig. 19 A , Fig. 20 M ). Proboscis cylindrical, three times longer than wide, with a declination of 30° with respect to the horizontal ( Fig. 19 A , Fig. 20 A–B). Triangular mouth, each lip lined with a dense fringe of setae and a row of 7–9 small soft papillae ( Fig. 20 C ).

Three articled chelifore. Single articled scape extends beyond the proboscis ( Fig. 19 A ), narrower in the middle and wider at both ends, with a mid-dorsal seta, two dorso-distal setae and a distal-ventral seta. Chelae well developed, without teeth, with three ventro-distal setae and three dorso-distal setae ( Fig. 19 B ; Fig. 20 D ). Palps absent.

Oviger inserted just below the first pair of legs in the male, with six articles ( Fig. 19 A ); article small, thicker than other articles, glabrous. Second article 2.8 times longer than the first one, with a mid-ventral and a ventro-distal seta. Third article longest, 5.8 times longer than the first one, with six ventral setae in the first third followed by a bulge and a row of nine setae; and three dorsal setae. Fourth article arched, 1.6 times longer than the first, with a mid-dorsal seta. Fifth article of the same size as the first one, with seven dorsal setae and a row of six ventral setae. Sixth article ½ the size of the first, with four setae (only visible in Fig 19 A, G ) on distal end ( Fig. 19 A, G , Fig. 20 B, K ). The oviger, in the only juvenile specimen collected, is a short structure formed by three glabrous article.

Thin legs ( Fig. 19 C , 20 F ). Coxa 1 small, semi-circular, glabrous. Coxa 2, twice as long as coxa 1, in males with a swelling on the first third of the dorsal part, three mid-ventral spines and prominent ventro-distal genital spur covered with small spines ( Fig. 19 D ). Coxa 3 narrow proximally and widened distally, with two ventro-distal setae. Femur longest with a conical mid-dorsal cement gland ( Fig. 19 C , Fig. 20 G–I), three dorsal setae after the cement gland and one dorso-distal seta; with two ventral setae on the first third and five ventral setae on the last third. Tibia 1 narrow proximally and widened distally, with three mid-ventral setae, five dorsal setae on the first ½ of the segment and three setae on the dorso-distal end, anterior one thicker. Tibia 2 longest with seven ventral setae, eight dorsal setae and two latero-distal setae. Tarsus with a dorso-distal seta, two mid-ventral setae, two ventro-distal setae and two latero-distal setae. Propodus arched, with a dorsal row of eight spines and 4 lateral spines; heel with a thin basal seta, two thick and two thinner setae; two rows of seven ventral sole spines directed towards the distal end. Main claw ¾ propodus length, with a pair of tiny lateral auxiliary claws ( Fig. 19 C, F ; Fig. 20 J ).

Female: Anoplodactylus erectus females differ from the males by the absence of ovigers. Other difference between male and female is the coxa 2 e in females, widened anteriorly, without genital spur, with a group of 6 distal setae and a tiny subdistal setae ( Fig. 19 E ).

Measurements of the illustrated specimen (mm): Trunk: 1.09 from the anterior limit of the cephalic segment to the limit of the fourth lateral process, 0.7 wide between the second pair of lateral processes; proboscis 0.33 mm long, 0.14 mm wide.

Third leg: Coxa 1, 0.24; coxa 2, 0.56; coxa 3, 0.32; femur, 1.02; tibia 1, 0.85; tibia 2, 0.95; tarsus, 0.1; propodus, 0.41; main claw, 0.34.

Oviger: 1) 0.09; 2) 0.22; 3) 0.47; 4) 0.18; 5) 0.1; 6) 0.05.

Distribution. Anoplodactylus erectus is a widely distributed species from San Diego, California, USA to Malpelo Island in the Colombian Pacific ( Cole 1904; Child 1979). In the Western Child (1970) reported the species from French Polynesia and. M̹ller (1989) collected A. erectus from Bora Bora Island. Nakamura & Child (1991) reported this species from the Kyushu Islands and Amakusa, Japan. The present report from Bahía de La Paz falls within the known range but is an extension of the distribution to the southwestern part of the Gulf of California (La Paz is about 1,600 km south of the closest previous location at San Diego, California, USA).

Remarks. The specimens of the present study differ from the holotype described by Cole (1904) in the length and ornamentation of the propodus. The holotype has a semi-straight propodus, with five spines on the heel, the first two setae thicker than the rest, nine curved ventral sole spines, and a propodal lamina that occupies the final third, with five setae, two on the posterior middle part and three on the distal part. Main claw thin and long, almost touching the heel, short auxiliary claws, one tenth of the main claw length. The specimens from the east coast of Baja California Sur have an arched propodus, with seven spines along the segment and a row of four lateral setae; heel with two thick spines and two pairs of smaller spines. Sole with two ventral row of six blunt, curved sole spines, directed towards the anterior end, short propodal lamina, 1/5 of the length of the propodus; thick main claw, slightly longer than ½ of the propodus, with tiny auxiliary claws, barely visible even with scanning electron microscopy ( Fig. 20 J ).

The specimens reported by M̹ller (1989) from Bora Bora Island have a propodus similar to the specimens collected in the present study, except for differences in the number of setae, other morphological characters are similar.

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 19. Anoplodactylus erectus UANL-FCB-PYCNO-0081, male: A, trunk, lateral view; B, chelae, enlarged; C, third leg; D, coxa 2, male; E, coxa 2, female; F, propodus, enlarged; G, Oviger, male. Scale bars: C–E = 0.5 mm; A = 0.3 mm; B, F–G = 0.1 mm.

FIGURE 20. Anoplodactylus erectus, UANL-FCB-PYCNO-0081, male: A, trunk, dorsal view; B, trunk, ventral view; C proboscis and mouth, frontal view; D, chelifore, enlarged; E, ocular tubercle, frontal view; F, third leg; G, third and fourth legs; H, cement gland, enlarged; I, femur side view, showing position of cement gland; J, tarsus, propodus, and claw, enlarged; K, terminal articles of oviger; L, coxa 2, male genital spur, enlarged; M, abdomen, lateral view. Scale bars: F = 2 mm; G = 1 mm; A–B = 0.5 mm; E = 0.3 mm; I–J, L = 0.2 mm; C–D, H, K, M = 0.1 mm.