Nymphon apheles Child, 1979

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 : 178

Nymphon apheles Child, 1979

( Figs . 14 A–G; 15 A–I )

Nymphon apheles Child, 1979: 35–37 , fig. 12.

Material examined. Four specimens: 4³, (UANL-FCB-PYCNO-0068), Cantamar Marine, 24°16´44´´N, - 110°19´51´´W, 26/06/2017 ( Fig. 1 ).

Description. Male. Trunk completely segmented. Neck short, cylindrical, widened anteriorly; cephalon Yshaped, with a pair of conical projections at the anterior end ( Fig. 14 A–B). Lateral processes separated by less than their own diameter in all segments ( Fig. 14 A ; Fig. 15 A ). Ocular tubercle inserted in front of the first pair of lateral processes, conical, with two small papilliform lateral projections and two pairs of oval eyes ( Fig. 14 A–B; Fig. 15 A, D ). Abdomen extends past lateral processes of fourth pair of legs, rises at a 45° angle upward, has two pairs of lateral setae and several rows (in groups of two or three) of smaller setae ( Fig. 14 A–B, Fig. 15 I ). Proboscis cylindrical, 1.5 times longer than wide, with a downward inclination of 40° with respect to the horizontal axis of the body ( Fig. 14 B , Fig. 15 A, C, F ), covered by groups of two setae each in longitudinal rows ( Fig. 15 C ). Mouth with three lips, each lip with a row of three papillae, and a band of setae ( Fig. 15 B ).

Two-articled chelifore formed by two articles, scape slightly longer than chela, cylindrical, as long as the proboscis, with a mid-dorsal seta ( Fig. 14 B ). Thin chelae, each with a row of four dorsal setae ( Fig. 14 A, C ). Immovable and movable fingers each with nine teeth, distal ends slightly curved ( Fig. 14 C ; Fig. 15 C ).

Palp with five articles, second one is the longest. First article short, cylindrical, glabrous. Second and third articles 2.5 and 2.3 times longer than the first article, each one with a ventro- distal seta. Fourth article1.2 times longer than the first one, with two ventro-distal setae. Fifth article1.8 times longer than the first one, with a mid-ventral and a lateral seta, and seven to ten distal setae ( Fig. 14 D ; Fig. 15 E, F ).

Ovigers insert below the first pair of lateral processes ( Fig. 14 B ). First to third articles short, glabrous, equal in size. Fourth article 2.5 times longer than first, glabrous. Fifth article longest, 2.8 times longer than the first, with a dorso-distal seta. Sixth article twice as long as first one, with a dorso-distal seta. The four terminal article that form the strigilis each have one or two dorso-distal setae, and are armed with ventral denticulate compound spines in the formula: 5: 4: 2: 3. These compound spines are composed of 3–4 pairs of lateral teeth depending on the size. The terminal claw is the same length as article ten, curved, and armed with three teeth ( Fig. 14 F–G; Fig. 15 G–H).

Legs thin. Coxa 1 short, with single latero-distal seta. Coxae 2 and 3, are 2 and 1.5 times longer than coxa 1, both with a ventro-distal seta. Femur longer than coxae 1 to 3 combined, with two dorsal setae, distal one on a low protuberance, and two mid-ventral setae. Tibia 1 with a row of five dorsal setae and a mid-ventral seta. Tibia 2 longest, with a row of six setae, the distal-most one is the longest, and two ventro-distal setae. Tarsus with a mid-ventral seta and a ventro-distal seta. Propodus slightly curved, with six dorsal spines and seven ventral sole spines. Main claw short, 1/4 the length of the propodus, auxiliary claws ¾ the length of the main claw ( Fig. 14 E ).

Measurements of the illustrated specimen (mm): Trunk: 1.1 mm long from the anterior part of the cephalic segment to the insertion of the fourth pair of lateral processes, 0.49 wide between the second pair of lateral processes. Proboscis: 0.36 mm long, 0.22 wide.

Third leg: Coxa 1, 0.13 coxa 2, 0.27; coxa 3, 0.15; femur, 0.56; tibia 1, 0.62; tibia 2, 0.88; tarsus, 0.09; propodus, 0.4; main claw, 0.12.

Oviger: 1) 0.12; 2) 0.12; 3) 0.31; 4) 0.36; 5) 0.24; 6) 0.19; 7) 0.14; 8) 0.12; 9) 0.12; 10) 0.13; 11) 0.12.

Distribution. Child (1979) described Nymphon apheles for Punta Paitilla, Pacific coast of Panama. The present record of N. apheles in the Gulf of California is the first report since 1979 and extends the distribution of the species about 3,900 km north from Panama.

Remarks. The genus Nymphon currently includes 255 nominal species in the world, of which only three have been reported in Mexico: Nymphon pixellae Scott, 1912 , Nymphon floridanum Hedgpeth, 1948 and Nymphon lituus Child, 1979 . Child (1979) described it on the basis of a juvenile female specimen. Of the four adult specimens collected in the present study, two were males with egg masses attached to the ovigers and two were females. The present study includes the first description of a male of N. apheles . Specimens from the Gulf of California have only three morphological differences compared to the holotype from Panama: presence of two proximal and two distal setae on the abdomen, as well as, the strigilis formula; which is 5: 5: 2: 3 in the holotype and 5: 4: 2: 3 in the specimens of the present work. The rest of the morphological characters were 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 14. Nymphon apheles, UANL-FCB-PYCNO-0068, male: A, trunk, dorsal view; B, trunk, lateral view; C, chelae, showing finger details, enlarged; D, palp; E, third leg; F, oviger; G, strigilis, enlarged. Scale bars: A–B, D–E = 0.5 mm; C, F–G = 0.1 mm.

FIGURE 15. Nymphon apheles, UANL-FCB-PYCNO-0068, male: A, trunk, dorsal view; B, proboscis, showing mouth detail and papillae (pap), distal end; C, proboscis, palp, and chelae, ventral view; D, ocular tubercle, lateral view; E, palp; F, trunk, ventral view; G, oviger; H, strigilis, enlarged; I, abdomen, dorsal view. Scale bars: A, F = 0.5 mm; C, E–G = 0.2 mm; H–I = 0.1 mm; B, D = 0.05 mm.