Varohios topianus J. L. Barnard 1979

Varohios topianus

DESCRIPTION OF MALE.—Eyes subovate, with black core surrounded by 3 or 4 layers of tiny ommatidia. Upper lip broadly rounded below, prebuccal parts rounded anteriorly, no epistomal spike. Lower lip, maxilla 2 and dactyls of pereopods 1–2 as shown for Zoedeutopus cinaloanus; only right mandibular molar with small plumose seta. Hand (article 5) of gnathopod 1 with secondary palmar tooth inside chela. Uropod 1 with immense interramal tooth, uropod 2 lacking interramal tooth. Pleonites 4–5 each with 1 dorsolateral seta on each side marking dorsal limit of pellucid chitinous sleeve overlapping next posterior segment. Telson with short, deep dorsoposterior excavation guarded by stout spine each side, pair of lateral setae each side, 1 distal setule each side, 1 small boss each side and lateral to setule. Pereonal sternites lacking teeth.

Pigment in alcohol; following parts covered with dark purple brown pigment: pereonites 4–5, posterior half of coxa 4, dorsoposterior parts of head or scattered lightly over entire head; uropods 1–2 bearing peduncular bands of similar pigment, pereonites 5, 7, pleonites 1, 2 each with small dorsal spot, coxa 2 with medium density spot on posteroventral face, coxa 5 with scattered pigment on anteroventral face, pleonites 1–2 with scattered lateral pigment, bases of pleopods behind epimera 1–3 outlined with diffuse purple pigment.

FEMALE (largest, 2.88 mm).—Gnathopod 1 smaller than gnathoped 2, gnathopods as illustrated herein for juvenile. Pigment similar to male but pigment dark on head, pereonites 1–2, coxae 1–2, no pigment on pereonites 4–5 and dorsal spots present only on pereonite 7 and pleonite 1.

HOLOTYPE.—USNM 142349, male “a,” 2.53 mm (illus.); pereopod 4 missing both sides.

TYPE-LOCALITY.—PAZ 19, Baja California, 11 km E of Cabo San Lucas, 4 December 1971, intertidal, from small polychaete-like (possibly amphipod tubes of this species).

VOUCHER MATERIAL.—Type-locality, male “m,” 2.61 mm (illus.), juvenile “j,” 1.57 mm (illus.).

MATERIAL.—PAZ 3, 12, 13, 19; GAL 108; DAW 16.

DISTRIBUTION.—Gulf of California at Bahía San Evaristo, Isla Espiritu Santo and Cabo San Lucas, 0 m; Galapagos Islands, 0 m.

Zoedeutopus, new genus

DIAGNOSIS.—Lateral cephalic lobes strongly produced, antenna 2 deeply inserted along ventral cephalic margin. Mandibular palp articles 2 and 3 subequal in length to each other, article 3 linear, setose apically, article 1 more than half as long as articles 2–3. Mandibular lobes of lower lip subacute. Inner plate of maxilla 1 broadly expanded, apically rounded, bearing 2 facial setae. Gnathopod 1 larger than gnathopod 2 in female, in male enlarged and of Microdeutopus-form, carpochelate, article 6 shorter and narrower than article 5, gnathopod 2 in male also enlarged and larger than gnathopod 1, weakly carpochelate, article 6 shorter and narrower than article 5, chelate. Rami of uropod 3 subequally long but inner distinctly shorter than outer, latter with distinct article 2. Telson ordinary.

TYPE-SPECIES.—Zoedeutopus cinaloanus, new species.

RELATIONSHIP.—This genus superficially resembles Microdeutopus Costa, which has been monographed by Myers (1969). Zoedeutopus cinaloanus resembles the armatus-chelifer group of that genus in which male gnathopod 2 is enlarged and propodochelate but Zoedeutopus differs from Microdeutopus generally in the deeply inserted antenna 2, the short, linear article 3 of mandibular palp on which all setae are terminal, in the facial and not apical setae on the inner plate of maxilla 1, and in the presence of a distinct article 2 on the outer ramus of uropod 3. In these respects, especially the head and uropod 3, Zoedeutopus appears to belong to the group of genera including Neomegamphopus Shoemaker, Amphideutopus J. L. Barnard, Acuminodeutopus J. L. Barnard, Konatopus J. L. Barnard, from the east tropical Pacific and Hawaii, all of which have the Microdeutopus-like male gnathopod 1. Those four genera may be divided into two groups based on the flabellate expansion of article 3 on the mandibular palp in Amphideutopus, Neomegamphopus, and Konatopus, and its simple, linear condition in Acuminodeutopus and Zoedeutopus. The new genus appears to be the most primitive member of this generic group, because of the simple article 3 of the mandibular palp, moderate insertion of antenna 2 (deep but not as extreme as in the other genera), and the slight shortness of the inner ramus of uropod 3. The facial setae on the inner plate of maxilla 1, however, may be an advancement. Acuminodeutopus appears to be the most closely related genus to Zoedeutopus but is more specialized by virtue of the strong shortening of the inner ramus on uropod 3 while retaining the small male gnathopod 2 typical of Microdeutopus. Zoedeutopus is peripheral to the triangle of Amphideutopus-Neomegamphopus-Konatopus discussed by J. L. Barnard (1970:70), a group characterized by shortening of the outer ramus of uropod 3 or the precise equality of both rami, bears the enlarged male gnathopod 2 characteristic of Amphideutopus and in Neomegamphopus and Konatopus has article 4 of the maxillipedal palp reduced in size. In the four genera related to Zoedeutopus the setae on the inner plate of maxilla 1 appear to have migrated to the medial margin.

In a phyletic sequence one would place Zoedeutopus in the center, with Acuminodeutopus forming one line of descent and Amphideutopus forming the first member of a second line of descent, followed by Neomegamphopus. The Hawaiian Konatopus would appear to be descendent from Neomegamphopus.

These 5 genera, containing only 8 known species, form a group so far discovered only in East Africa, middle America, and Hawaii. The counterpart and presumedly more primitive ancestors comprise the genera Microdeutopus and Chevreuxius Bonnier from both tropical and cooler latitudes. A second counterpart, composed of Grandidierella Coutière and Neomicrodeutopus Schellenberg (=?Grandidierella) is found in the tropical eastern hemisphere but appears to be descendent from Microdeutopus because of the poorly inserted antenna 2.