Crinotonia, Marin, 2006

Marin, Ivan, 2006, Description Of Crinotonia Anastasiae, New Genus, New Species, A New Crinoid Associated Pontoniine Shrimp (Crustacea: Caridea) From Nha Trang Bay, Vietnam, With Inclusion Of Periclimenes Attenuatus Bruce, 1971, In The New Genus, Raffles Bulletin of Zoology 54 (2), pp. 321-340 : 322

Crinotonia , new genus

Diagnosis. – Symbiotic medium-sized shrimps associated with crinoids (feather stars). Carapace swollen, especially in females, and smooth, with antennal and small hepatic spines. Rostrum short, tapering, with well developed lamina bearing two-four dorsal teeth, ventral teeth absent, lateral lamina feebly developed, continuous with orbital margin posteriorly. Orbit feebly developed, inferior orbital angle rounded, slightly projecting. Pterygostomial margin bluntly angular. Abdominal somites smooth; pleura of first to fifth abdominal somites rounded, posterolateral angle of sixth abdominal somite pointed and posteroventral angle projecting and rounded. Telson with two pairs of dorsal and three pair of posterior spines. Eyes slightly projecting distally, with central corneal papillae. Antennule with large disto-lateral and one or two small teeth on distal medial lobe, robust ventral tooth in middle of medial border of basal segment. Antenna with disto-ventral tooth on basicerite and well developed blade of scaphocerite. Mouthparts without special features. Mandible without palp, with blade-like incisor process. Maxilla and maxillula with well developed palps. First maxilliped with distinct and well developed endites, large exopod with well developed caridean lobe bearing plumose setae, and epipod. Second maxilliped with well developed segments, exopod, epipod, without a podobranch. Third maxilliped with slender segments bearing setae, with well developed exopod and small epipod, without an arthrobranch. First pereiopod slender, with robust chela and broad, swollen fingers. Second pereiopods highly differ in size and shape; major pereiopod with robust segments, with long subcylindrical long palm, with robust fingers, fixed finger bearing two teeth opposing into deep pits on the dactylus; minor pereiopod is extremely slender, with simple slender fingers. Third pereiopod with unarmed segments; propodus with serrated ventral margin; dactylus is biunguiculate, with slender and curved unguis, ventral margin setose, unarmed or bearing small teeth, preterminal accessory tooth is stout and triangular in shape. Pleopods are normal, endopod of second pleopods in males with well developed appendix masculina bearing numerous terminal spines. Uropods slender, exceeding telson, lateral border of endopod with small distal tooth and mobile spine.

Type-species. – Crinotonia anastasiae , new species.

Included species. – Crinotonia anastasiae , new species, and Periclimenes attenuatus Bruce, 1971 .

Taxonomic remarks. – The new genus has a combination of morphological features which is unique in subfamily Pontoniinae : the absence of a podobranch on second maxilliped and an arthrobranch on the third maxilliped, the presence of several disto-lateral and robust mesial ventral teeth on the first antennular segment, the extreme second pereiopods dimorphism, the serrated ventral border of propodus of the third pereiopod and the absence of disto-ventral propodal spines, specialized dactylar form and dactylar dentition. The combination of these features is not found in any other genus of the subfamily. The most morphologically similar genus is Pontoniopsis Borradaile, 1915 with type species P. comanthi Borradaile, 1915 associated with Indo-Pacific crinoids. Pontoniopsis comanthi possesses similar morphological features as short rostrum, absence of podobranch on second and arthrobranch on third maxilliped, occurrence of several disto-lateral and robust mesial ventral teeth on basal antennular segment, extreme second pereiopods dimorphism and similar dactylar form and its dentition ( Figs. 11 , 12; see also Bruce, 1982). However, the genus Pontoniopsis clearly differs from Crinotonia , new genus, in having highly developed lateral rostral carina, toothless rostrum, absence on hepatic spine, subspatulate dactylus of minor second pereiopod, absence of clear serration of ventral margin and presence of small disto-ventral tooth on propodus of third pereiopod ( Figs. 11 , 12). Furthermore, representatives of P. comanthi are significantly smaller.

Etymology. – First part of the word “ Crino-” dealing with the hosts of this genus – crinoids (feather stars), and second “- tonia ” showed belonging to subfamily Pontoniinae . Gender: feminine.

Figures

Fig. 11. Pontoniopsis comanthi Borradaile, ovigerous female (PCL 1.5 mm), Mun Island, Nha Trang Bay: a, general view; b, front of carapace, dorsal view; c, antennule; d, antenna. Scale bar: a = 2 mm; b = 3 mm; c, d = 4 mm.