Portunus (Lupocycloporus) Alcock, 1899

Koch, Milan, Spiridonov, Vassily A. & Ďuriš, Zdeněk, 2023, Revision of the generic system for the swimming crab subfamily Portuninae (Decapoda: Brachyura: Portunidae) based on molecular and morphological analyses, Zoological Journal of the Linnean Society 197, pp. 127-175 : 144

= Portunus (Lupocycloporus) Alcock, 1899

Type species: Achelous whitei A. Milne-Edwards, 1861 , by monotypy; gender masculine.

Included species: Eight.

Lupocycloporus aburatsubo ( Balss, 1922)

= Neptunus buratsubo Balss, 1922

Lupocycloporus gracilimanus (Stimpson, 1858)

= Amphitrite gracilimanus Stimpson, 1858

= Achelous whitei A. Milne-Edwards, 1861 Lupocycloporus innominatus (Rathbun, 1909)

= Neptunus (Lupocycloporus) innominatus

Rathbun, 1909

Lupocycloporus laevis (A. Milne-Edwards, 1861)

= Neptunus laevis A. Milne-Edwards, 1861 Lupocycloporus minutus Shen, 1937

= Neptunus (Lupocycloporus) minutus Shen, 1937 Lupocycloporus ponticus (Fabricius, 1798) comb. nov.

= Portunus ponticus Fabricius, 1798

= Portunus ponticus Weber, 1795 (nomen nudum) Lupocycloporus sinuosodactylus (Stephenson, 1967)

= Portunus sinuosodactylus Stephenson, 1967 Lupocycloporus wilsoni (Moosa, 1981)

= Portunus (Lupocycloporus) wilsoni Moosa, 1981

Diagnosis: Carapace ( Fig. 7A) ~1.5 times as broad as long, approaching quasi-hexagonal shape, but with arcuate anterolateral margin, dorsally convex. Regions feebly developed, marked by granular ridges and patches. Front ( Fig. 7B) with four rounded or subtriangular lobes, median ones usually more producing than lateral ones; all lobes projecting beyond tips of inner supraorbital lobes, which are quasi-triangular in shape. Orbit nearly circular; supraorbital margin with two shallow, reduced fissures. Anterolateral margin armed with nine teeth: eight anterior ones increasing in size posteriorly or subequal, small, acute and projecting forwards; ninth tooth distinctly larger, lateral. Posterolateral angle of carapace broadly rounded. Sutures on thoracic sternum well developed ( Fig. 7C). Merus of third maxilliped with anteroexternal angle rounded or subrectangular, not produced laterally. Merus of chelipeds robust, with four to seven spines on anterior margin and two distal spines on posterior margin; carpus with spine on outer face. Chelae slender ( Fig. 7D), nearly equal, homoiodontic; palm with two subdistal spines on upper surface. Dactyli of pereiopods 2–4 cultriform, costate, weakly setose on ventral margin. Merus of pereiopod 5 distinctly longer than broad, with spine on posterior margin. Male pleon triangular ( Figs 4E, 7C). Pleomeres 2 and 3 with low crests; lateral margins of pleomere 3 rounded, narrowing distally; posterior margin of last thoracic episternite touches most of anterolateral margin of pleomere 3. Pleomeres 3–5 fused, without sutures remaining but keeled. First male gonopod ( Fig. 7E) relatively short and robust proximally, curved and tapering distally; pair of first gonopods lying obliquely, touching subdistal parts, with apices directed anterolaterally or laterally. Female vulva (examined in Lupocycloporus gracilimanus ) elongate, rounded on ends, located along most of the mesial margin of the sternite.

Systematic position: Lupocycloporus has a distinct general morphology and extremely slender homoidontic chelae, similar to the chelae of Lupocyclus . Indeed, species of these genera exhibit sister-group relationships in recent phylogenetic reconstructions, and both genera were included in a separate subfamily Lupocyclinae Paulson, 1875 ( Spiridonov et al., 2014; Evans, 2018). In the present phylogenetic reconstruction ( Fig. 1), Lupocycloporus spp. form a basally unsupported clade with Alionectes pulchricristatus . Given that Lupocycloporus and Alionectes share common apomorphies [i.e. the swimming leg merus with a distinct posterodistal acute tooth (below), elongately subtrianglar male pleon and laterally bent gonopods with a swollen basal part], these and other characters (see discussion under Alionectes ) might support their close relationship.