Morphometrical categorization of Phyllobothrium delphini (Cestoidea, Tetraphyllidea) cysts from Fraser's dolphin, Lagenodelphis hosei (Cetacea, Delphinidae)

Abstract

-The larvae of phyllobothriid cestode worms found in marine mammals have been classified as either "delphinii group" or "grimaldii group". The first group has been divided into 11 morphotypes by previous studies. However, these categories are vague and often overlap, as they were described from different host species within a wide geographical range. The goal of this study is to simplify the categorization of larval shape and size based on samples obtained from a single host species. Eleven Fraser's dolphin Lagenodelphis hosei Fraser, 1956 stranded on the coast of Uruguay in November 2001 and subsequently died. From these animals, 190 cysts of Phyllobothrium delphini (Bosc, 1802) were obtained from the perigenital blubber of one female and one male. The prevalence of P. delphini was 18.18%, density was 159.38 larvae/kg of perigenital blubber, mean intensity was 95 and mean abundance was 17.27. The following measurements were taken: total length (BL), width and thickness of cysts, neck length (NL), scolex length, scolex width, external diameter of the suckers, and the ratio BL/ NL. In order to facilitate further identification of these phyllobothriid cysts, they were grouped into three categories according to shape and size: category "A" (22.35%, neck always straight); category "B" (62.35%, all with curved neck); category "C" (15.30%, U-shaped or with projections from the wall of the cyst, also curved neck). These morphological differences could correlate to time spent in the host. One other larval form (Tetrabothrius sp.) was also found in the blubber of these dolphins.Resumen -Las larvas de filobotridios en mamíferos marinos fueron clasificadas como "grupo delphinii" y "grupo grimaldii". En estudios previos el primer grupo fue dividido en 11 morfotipos. Sin embargo, estas categorías son vagas y a menudo se solapan, ya que fueron descritas a partir de diferentes especies de hospedadores provenientes de una amplia distribución geográfica. El objetivo de este estudio es simplificar la categorización de tamaños y formas larvarias a partir de una muestra obtenida de un único hospedador. Se estudiaron once ejemplares muertos de Lagenodelphis hosei Fraser 1956 varados en la costa de Uruguay en noviembre de 2001. Ciento noventa quistes de Phyllobothrium delphini (Bosc, 1802) fueron obtenidas de la grasa perigenital de una hembra y un macho. La prevalencia de P. delphini fue del 18.18%, la densidad 159.38 larvas/kg de grasa perigenital, la intensidad media 95 y la abundancia media 17.27. Se tomaron las siguientes medidas: largo total (BL), ancho y grosor del quiste, largo del cuello (NL), largo del scolex, ancho del scolex, diámetro externo de las ventosas y el cociente BL/NL. Para facilitar futuras identificaciones, estas larvas filobotrídeas fueron agrupadas en tres categorías de acuerdo a su tamaño y forma: categoría "A" (22.35%, cuello siempre recto); categoría "B" (62.35%, todas con cuello curvado) y categoría "C" (15.30%, cuello curvado, quistes en forma de U o con proyecciones de la pared). Estas diferen...

Subcutaneous merocercoids of Clistobothrium sp. in two Cape fur seals (Arctocephalus pusillus pusillus)

“…According to the key of marine tapeworm larvae established by Jensen and Bullard (2010) , both merocercoids represent larval type XV. These merocercoids have a wide geographic distribution and have been reported in numerous cetacean species worldwide ( Norman, 1997 ; Abollo et al, 1998 ; Cornaglia et al, 2000 ; Failla Siquier and Le Bas, 2003 ; Beron-Vera et al, 2008 ; Colon-Llavina et al, 2009 ; Carvalho et al, 2010 ; Oliveira et al, 2011 ), but have also been reported from pinnipeds ( Rennie and Reid, 1912 ; Southwell and Walker, 1936 ; Bester, 1989 ; Pansegrouw, 1990 ; Stewardson and Fourie, 1998 ; McFarlane et al, 2009 ). In captive fur seals, two cases of phyllobothriidian merocercoids were reported ( Cordes and O'Hara, 1979 ; Mendonca, 1984 ).…”

“…As mentioned before, the historical names ‘ P. delphini ’ and ‘ M. grimaldii ’ — still used by some authors — are misleading as the adult cestodes of these merocercoids are not known and their assignment to the genera Phyllobothrium and Monorygma with the type species P. lactuca van Beneden, 1850 and M. perfectum van Beneden, 1853 (Diesing, 1863), respectively is invalid. The identification of these forms is complicated by the extensive variability of delphini-morphotypes ( Testa and Dailey, 1977 ), which might represent stages developing with time spent in a host ( Failla Siquier and Le Bas, 2003 ). Sequence analyses of the two merocercoid-types and LP- and SP-forms of plerocercoids suggested that they are congeneric and different species of the genus Clistobothrium ( Agusti et al, 2005a ).…”

Parasitic Anisakid Nematode Isolated from Stranded Fraser’s Dolphin (Lagenodelphis hosei Fraser, 1956) from Central Philippine Waters

“…In the Philippines, a multi-infection of A. typica, A. brevispiculata, and two unknown Anisakis species genetically close to A. paggiae and A. ziphidarum have been reported from Dwarf sperm whale (Quiazon et al 2013). Although other parasites have been reported in Fraser's dolphin such as Phyllobotrium delphini (cysrs and larval stage in blubber) (Cestoda, Tetraphyllidea), Monorygma grimaldii (in the abdominal cavity and urinary bladder) (Cestoda: Phyllobothriidae), and Tetrabothrius forsteri (Cestoda: Tetrabothriidae) (Carvalho et al 2010, Colón-Llavina et al 2009, Failla Siquier and Le Bas 2003, Mignucci-Giannoni et al 1999, Moreno et al 2003, the available parasite samples sent to the researchers for identification were mainly nematode fragments of Anisakis samples. Despite the identification of only Anisakis species in this study, it is likely possible that other endo-parasites are present but were not collected.…”