Pygmy Sperm Whale Kogia Breviceps Research Articles

Anisakid parasite diversity in a pygmy sperm whale, Kogia breviceps (Cetacea: Kogiidae) stranded at the edge of its distribution range in the Northeast Atlantic Ocean.

Anisakid nematodes are a globally distributed group of marine mammal parasites. Kogiid whales, including the pygmy sperm whale Kogia breviceps, host an assemblage of specific anisakid species. Currently, three species are known to be specific to kogiid hosts, i.e., Skrjabinisakis paggiae, S. brevispiculata, and the less studied Pseudoterranova ceticola. The aim of this study was to investigate the species diversity of anisakid nematodes sampled from a pygmy sperm whale stranded in 2013 at the edge of its distribution range in the Northeast Atlantic, specifically in the North of Scotland. Nematodes were assigned to genus level based on morphology and identified by sequence analysis of the mtDNA cox2 gene and the rDNA ITS region. The present finding represents the first observation of syntopic occurrence of adult stages of S. brevispiculata, S. paggiae, and P. ceticola in a pygmy sperm whale in the Northeast Atlantic, and represent the northernmost record of these species in this area. Skrjabinisakis brevispiculata was the most abundant species, accounting for 55% of the identified nematodes, predominantly in the adult stage. Anisakis simplex (s.s.) was also abundant, with most specimens in the preadult stage, followed by S. paggiae and P. ceticola. The pygmy sperm whale is rarely documented in Scottish waters, and its occurrence in the area could suggest expansion of its geographic range. The presence of S. brevispiculata, S. paggiae, and P. ceticola in this whale species in this region may indicate a shift in the whole host community involved in the life cycle of these parasites in northern waters. However, it is also plausible that these parasites were acquired while the whale was feeding in more southern regions, before migrating northbound.

Cochlear apical morphology in toothed whales: Using the pairing hair cell-Deiters' cell as a marker to detect lesions.

The apex or apical region of the cochlear spiral within the inner ear encodes for low-frequency sounds. The disposition of sensory hair cells on the organ of Corti is largely variable in the apical region of mammals, and it does not necessarily follow the typical three-row pattern of outer hair cells (OHCs). As most underwater noise sources contain low-frequency components, we expect to find most lesions in the apical region of the cochlea of toothed whales, in cases of permanent noise-induced hearing loss. To further understand how man-made noise might affect cetacean hearing, there is a need to describe normal morphological features of the apex and document interspecific anatomic variations in cetaceans. However, distinguishing between apical normal variability and hair cell death is challenging. We describe anatomical features of the organ of Corti of the apex in 23 ears from five species of toothed whales (harbor porpoise Phocoena phocoena, spinner dolphin Stenella longirostris, pantropical spotted dolphin Stenella attenuata, pygmy sperm whale Kogia breviceps, and beluga whale Delphinapterus leucas) by scanning electron microscopy and immunofluorescence. Our results showed an initial region where the lowest frequencies are encoded with two or three rows of OHCs, followed by the typical configuration of three OHC rows and three rows of supporting Deiters' cells. Whenever two rows of OHCs were detected, there were usually only two corresponding rows of supporting Deiters' cells, suggesting that the number of rows of Deiters' cells is a good indicator to distinguish between normal and pathological features.

Occurrence of Anisakis spp. (Nematoda: Anisakidae) in a pygmy sperm whale Kogia breviceps (Cetacea: Kogiidae) in Australian waters.

Little is known about parasitism in the pygmy sperm whale Kogia breviceps. Here, the occurrence of 3 anisakid species in a female pygmy sperm whale found stranded at Baxter's Beach, Australia, is reported, along with histopathological findings from this whale. Thirty-nine nematodes were submitted to the Parasitology Laboratory of Charles Sturt University for identification, where 37 of them were identified to species level as Anisakis berlandi (n = 13), A. brevispiculata (n = 19), and A. paggiae (n = 5), using a combined molecular and morphological approach. This is the first report of A. paggiae in Australian waters. The other 2 specimens were Anisakis spp. females but could not be identified to species level due to a lack of taxonomically important features. ITS sequence data for these 2 specimens were considerably different from one another and from previously known Anisakis spp. The nomenclatures of the new species remain pending until male adults are found and described. The histopathological findings in the present study suggest that despite occurring in large numbers, Anisakis spp. do not have an adverse impact on the host's stomach; however, the damaged intestinal mucosa and floating eggs found during histopathological examination of the intestinal tissue suggest that these parasites can have an adverse impact on the host's intestine, which may lead to malnutrition and stress.

Habitat use pattern of the giant parasitic nematode Crassicauda magna within the pygmy sperm whale Kogia breviceps.

The giant (>3 m) parasitic nematode Crassicauda magna infects kogiid whales, although only 3 studies to date have provided detailed descriptions of these worms, all based upon fragmented specimens. These fragments were found within the neck region of kogiids, an unusual anatomic site for this genus of parasites. C. magna is a species-specific parasite among kogiids, infecting only pygmy sperm whales Kogia breviceps, and with a primarily cervico-thoracic distribution. To date, however, the pattern of habitat use within the host and transmission path of this parasite remain unknown. We used detailed dissections (n = 12), histological examination of host tissues (n = 2), and scanning electron microscopy of excised nematodes (n = 7) to enhance our understanding of this host-parasite relationship. Results revealed that a critical habitat for the parasite is an exocrine gland in the whale's ventral cervical region. C. magna male and female tails were found intertwined within the glandular lumen, and eggs were observed within its presumed secretion, illuminating the transmission path out of the host. The cephalic ends of these worms were often meters away (curvilinearly), embedded deeply within epaxial muscle. A single worm's complete, tortuous 312 cm course, from the gland to its termination in the contralateral epaxial muscle, is described for the first time. This study also provides the first scanning electron micrographs of C. magna, which illustrate taxonomically important features of the heads and tails of both male and female worms.

Cryptosporidium spp. and Giardia sp. in aquatic mammals in northern and northeastern Brazil.

Cryptosporidium and Giardia are protozoans that can infect humans and wild and domestic animals. Due to the growing importance of diseases caused by protozoan parasites in aquatic species, we aimed to evaluate the frequency of infection by Cryptosporidium spp. and Giardia sp. in aquatic and marine mammals in the northern and northeastern regions of Brazil. We collected 553 fecal samples from 15 species of wild-ranging and captive aquatic mammals in northern and northeastern Brazil. All samples were analyzed by the Kinyoun technique for identification of Cryptosporidium spp. oocysts. Giardia sp. cysts were identified by means of the centrifugal-flotation technique in zinc sulfate solution. Subsequently, all samples were submitted for direct immunofluorescence testing. The overall frequency of infection was 15.55% (86/553) for Cryptosporidium spp. and 9.04% (50/553) for Giardia sp. The presence of Cryptosporidium spp. was detected in samples from 5 species: neotropical river otter Lontra longicaudis (15.28%), giant otter Pteronura brasiliensis (41.66%), Guiana dolphin Sotalia guianensis (9.67%), Amazonian manatee Trichechus inunguis (16.03%), and Antillean manatee T. manatus (13.79%). Giardia sp. was identified in L. longicaudis (9.23%), P. brasiliensis (29.16%), pygmy sperm whale Kogia breviceps (100%), dwarf sperm whale K. sima (25%), S. guianensis (9.67%), T. inunguis (3.81%), and T. manatus (10.34%). This is the first report of Cryptosporidium spp. in L. longicaudis, P. brasiliensis, and S. guianensis, while the occurrence of Giardia sp., in addition to the 2 otter species, was also identified in manatees, thus extending the number of hosts susceptible to these parasitic agents.

Anisakis Dujardin, 1845 infection (Nematoda: Anisakidae) in Pygmy Sperm Whale Kogia breviceps Blainville, 1838 from west Pacific region off the coast of Philippine archipelago.

Cetaceans are definitive hosts of anisakid nematodes known to cause human anisakidosis. Despite the reported strandings of different cetaceans in the Philippines, studies on anisakids from these definitive hosts are limited. Here, the morphologically and molecularly identified anisakid species, specifically those of the genus Anisakis Dujardin, 1845 in stranded Pygmy Sperm Whale Kogia breviceps Blainville, 1838 in the west Pacific region off Philippine waters are presented. Morphological data using SEM and LM revealed multi-infections with different Anisakis species belonging to Anisakis type I and type II groups. Molecularly, PCR-RFLP on the ITS rDNA and sequence data analyses of both ITS rDNA and mtDNA cox2 regions identified those from Anisakis type I group as A. typica (Diesing, 1860), whereas those from type II group as A. brevispiculata Dollfus, 1968, and A. paggiae Mattiucci et al. (Syst Parasitol 61:157-171, 2005). This is the first record of Anisakis infection from this host stranded in the west Pacific region off the coast of Philippine waters and new geographical record for A. paggiae.

Species identity and human consumption of beaked whales in the Gilbert Islands, Republic of Kiribati

AbstractWe investigated the species identity and local use of cetaceans on the Gilbert Islands, Republic of Kiribati. Working with the Kiribati Ministry of Environment, Lands and Agricultural Development and Fisheries Division, we visited the islands of Tarawa, Tabiteuea (North), Butaritari and Onotoa from June to July 2009, and collected 24 bones, bone fragments or teeth attributed to recent strandings. The mitochondrial DNA control region or cytochrome b was successfully amplified from 12 bones or bone fragments and used to identify four species: Mesoplodon sp. representing a new species or subspecies of beaked whale, the dense‐beaked whale Mesoplodon densirostris, Cuvier's beaked whale Ziphius cavirostris and the pygmy sperm whale Kogia breviceps. This is the first confirmed identification of the dense‐beaked, Cuvier's and pygmy sperm whales from the Gilbert Islands. All specimens were reportedly used for human consumption.

Structure, material characteristics and function of the upper respiratory tract of the pygmy sperm whale

Cetaceans are neckless, so the trachea is very short. The upper respiratory tract is separate from the mouth and pharynx, and the dorsal blowhole connects, via the vestibular and nasopalatine cavities, directly to the larynx. Toothed cetaceans (Odontoceti) are capable of producing sounds at depth, either for locating prey or for communication. It has been suggested that during dives, air from the lungs and upper respiratory tract can be moved to the vestibular and nasal cavities to permit sound generation to continue when air volume within these cavities decreases as ambient pressure rises. The pygmy sperm whale, Kogia breviceps, is a deep diver (500-1000 m) that is known to produce hunting clicks. Our study of an immature female shows that the upper respiratory tract is highly asymmetrical: the trachea and bronchi are extremely compressible, whereas the larynx is much more rigid. Laryngeal and tracheal volumes were established. Calculations based on Boyle's Law imply that all air from the lungs and bronchi would be transferred to the larynx and trachea by a depth of 270 m and that the larynx itself could not accommodate all respiratory air mass at a depth of 1000 m. This suggests that no respiratory air would be available for vocalisation. However, the bronchi, trachea and part of the larynx have a thick vascular lining featuring large, thin-walled vessels. We propose that these vessels may become dilated during dives to reduce the volume of the upper respiratory tract, permitting forward transfer of air through the larynx.

Narrow band high frequency clicks from Hourglass dolphins (Lagenorhynchus cruciger)

The source properties of toothed whale echolocation clicks are essential for evaluating the performance of biosonar systems. However, such data only exist for a small number of free ranging toothed whale species. Here we present a quantitative analysis of the first recordings of echolocation sounds from hour glass dolphins (Lagenorhynchus cruciger) made in the Drake Strait. Recordings were made with a vertical array of four broad‐band, calibrated hydrophones that allows for acoustic localization and source parameter derivation. Only apparent on‐axis clicks were used for analysis. Hour glass dolphins produce clicks with a mean peak and centroid frequency around 128kHz, a narrow, mean RMS bandwidth of 10kHz with no energy below 100kHz and a mean signal duration of 161μs. Echolocation clicks of hour glass dolphins are thus of the high frequency narrow band‐width type (NBHF type) found in porpoises, a few delphinids of the Cephalorhynchus genus and the pygmy sperm whale Kogia breviceps, but are strikingly different from other dolphins. Acoustic convergence from vastly different genera and ecotypes suggest that evolution of NBHF clicks are adaptations to special auditory processing or acoustic crypsis rather than to habitat.

PORPOISE CLICKS FROM A SPERM WHALE NOSE—CONVERGENT EVOLUTION OF 130 KHZ PULSES IN TOOTHED WHALE SONARS?

ABSTRACT Small toothed whales of the family Phocoenidae and delphinid genus Cephalorhynchus produce long-duration, narrowband biosonar clicks above 100 kHz, that might be seen as an adaptation for short range echolocation in shallow water. This paper presents data showing that the distantly related, and larger pygmy sperm whale Kogia breviceps (Kogiidae), that is a deep-diving, cephalopod-eating toothed whale, produce narrow-banded high frequency (NBHF) clicks identical to those of Phocoena and Cephalorhynchus (f0 = 130 kHz, Q3dB>10, duration > 80 msec). Thus, NBHF biosonar signals have evolved on three independent occasions in the odontocete suborder, but the apparent functional convergence does not relate to anatomical or niche similarity. Rather, it is suggested that a biosonar strategy adapting to a minimum in ocean ambient noise above 100 kHz in concert with high Q auditory filters have led to convergent evolution of the NBHF biosonar clicks. Since these biosonar signals carry all their energy at frequencies above the upper hearing limit of the killer whale Orcinus orca, predator avoidance may also have been a evolutionary shaping factor of the sonar signals from these non-whistling odontocetes.

The first description of the double-bellied condition of the digastric muscle in the finless porpoise Neophocaena phocaenoides and Dall's porpoise Phocoenoides dalli

In Humans, the digastric muscle, one of the suprahyoid muscles, consists of two parts, or bellies, which are connected by an intermediate tendon, which in turn is connected to the body of the hyoid bone by a loop of fibrous connective tissue. The anterior belly of the digastric muscle is supplied by the trigeminal nerve, and the posterior belly by a facial nerve (Woodburne and Burkel 1994). The form of the digastric muscle has been described in so many mammals (Dobson 1879; Bijvoet 1908; Toldt 1908; Getty 1975; Tomo et al. 1998), that Bijvoet (1908) classified dozens of mammalian species into three groups based on the anatomy of their digastric muscles. These three groups are: 1) mammals with no digstric, 2) mammals whose digastric has two bellies united by an intermediate tendon, and 3) mammals with a digastric muscle lacking an intermediate tendon between the two bellies. All examples with double bellies are innervated by both facial and trigeminal nerves. According to Getty (1975), horses have a double-bellied digastric muscle, which arises from the jugular process of the occipital bone and attaches to the mandible, while the singlebellied condition is reported in pigs and goats, in which the posterior bellies are considered to be degenerated. Dogs have a single-bellied muscle that runs from the paracondylar process of the occiput to the ventral border of the mandible. But Evans (1993) stated that “although it appears as a single-bellied muscle in the dog, a tendinous intersection and innervation by both the n. trigeminus and the n. facialis are evidence of its dual nature. Thus, the two parts of the muscle are referred to as the rostral belly and the caudal belly.” Various old descriptions seem to refer to a doublebellied condition among the odontoceti. The M. occipitohyoideus of the harbor porpoise Phocoena phocoena described by Rapp (1837) and Stannius (1849) can be interpreted, based on their origin and insertion, as the homologue of the posterior belly of the digastric muscle. Schulte and Smith (1918) described a “hyomandibularis” and a “depressor mandibulae” in the pygmy sperm whale Kogia breviceps on the basis of the innervation of those two muscles, which makes them equivalent to the anterior and posterior bellies of the digastric. Subsequently, however, the digastric has been described as a singlebellied muscle in many odontocetes, such as the narwhal Monodon monoceros (Howell 1930), striped dolphin Stenella coeruleoalba (Hosokawa and Kamiya 1965; Lawrence and Schevill 1965; Werth 1992; Reidenberg and Laitman 1994), Atlantic spotted dolphin S. frontalis (Lawrence and Schevill 1965), Pacific white-sided dolphin Lagenorhynchus obliquidens (Reidenberg and Laitman 1994), Atlantic white-sided dolphin L. acutus (Lawrence and Schevill 1965; Werth 1992; Reidenberg and Laitman 1994), whitebeaked dolphin L. albirostris (Lawrence and Schevill 1965; Werth 1992), common dolphin Delphinus delphis (Lawrence and Schevill 1965; Pilleri 1976; Werth 1992; Reidenberg and Laitman 1994), bottlenose dolphin Tursiops truncatus (Lawrence and Schevill 1965; Werth 1992; Reidenberg and Laitman 1994), Risso’s dolphin Grampus griseus, long-finned pilot whale Globicephala melas (Werth 1992; Reidenberg and Laitman 1994), killer whale Orcinus orca (Werth 1992), True’s beaked whale Mesoplodon mirus, Gervais’ beaked whale M. europaeus (Reidenberg and Laitman 1994), sperm whale Physeter macrocephalus (Werth 1992; Reidenberg and Laitman 1994), dwarf sperm whale K. sima (Reidenberg and Laitman 1994), and even in the finless porpoise Neophocaena phocaenoides

SEM study of <i>Anisakis brevispiculata</i> Dollfus, 1966 and <i>Pseudoterranova ceticola</i> (Deardoff and Overstreet, 1981) (Nematoda: Anisakidae), parasites of the pygmy sperm whale <i>Kogia breviceps</i>

SUMMARY: Scanning Electron Microscopy (SEM) was used to study different topo-morphological characteristics of the architecture (cuticle, excretory pore, lips and adjacent structures, number and distribution patterns of caudal papillae and papillae-like structures) of the anisakid nematodes Anisakis brevispiculata and Pseudoterranova ceticola, parasites in the stomach of the pygmy sperm whale Kogia breviceps. SEM micrographs herein help to accurately define the above surface topographical features by adding a more adequate 3-D picture to the original descriptions of both parasitic species. In A. brevispiculata the entire body cuticle structure, well-differentiated paracloacal papillae and the wrinkle cuticle of the papillae are clear examples that enhance the above differentiation of structures as seen by LM or SEM. Similarly, in P. ceticola the cuticle striations, bulky cloacal lips, rectangular distribution pattern of distal papillae and the absence of a groove separating paracloacal papillae which are obliquely arranged are all different to those features previously described.

A novel trypanoplasm-like flagellate Jarrellia atramenti n. g., n. sp. (Kinetoplastida: Bodonidae) and ciliates from the blowhole of a stranded pygmy sperm whale Kogia breviceps (Physeteridae): morphology, life cycle and potential pathogenicity.

The successful 6 mo rehabilitation of a stranded juvenile pygmy sperm whale Kogia breviceps afforded the opportunity to study the poorly known protozoan fauna of the upper respiratory tract of cetaceans. Mucus samples were collected by holding either a petri dish or glass slides over the blowhole for 3 to 5 exhalations; preparations were examined as wet mounts, and then stained with Wrights-Giemsa or Gram stain. Blood smears were stained with Wrights-Giemsa. Unidentified spindle-shaped and unidentified broad ciliates, reported from the blowhole of the pygmy sperm whale for the first time, were seen only initially, while yeast-like organisms and bacteria were seen intermittently. Epithelial cells and white blood cells were often present in the blowhole mucus, but red blood cells were never seen. A novel trypanoplasm-like bodonid kinetoplastid biflagellate (Order Kinetoplastida) was commonly encountered in the blowhole mucus, but never in the blood. Both mature flagellates and those undergoing longitudinal binary fission were present. The elongate flagellate had a long whiplash anterior flagellum; the recurrent flagellum was attached along at least two-thirds of the body length, forming a prominent undulating membrane, and the trailing portion was short. The kinetoplast was irregularly fragmented. The flagellates were either free-swimming, or attached to host material via the free portion of the posterior flagellum. The prominent undulating membrane was characteristic of Trypanoplasma, while the fragmented kinetoplast was characteristic of some species of Cryptobia. For the novel bodonid kinetoplastid, with its unique combination of morphological features (prominent undulating membrane and fragmented kinetoplast), we propose the creation of a new genus Jarrellia. We believe this to be the first published description of a flagellate from a marine mammal, and among the first reports of a trypanoplasm-like flagellate from a warm-blooded host. We expect that a diversity of flagellates and ciliates are commonly present in the blowhole of cetaceans. Future studies on the identity of the protozoans and the health of their cetacean hosts, which are readily studied in captivity, are necessary to establish their status as commensals or parasites.

A new species of Isocyamus (Amphipoda: Cyamidae) from Kogia breviceps (De Blainville, 1838) in Australian waters

Isocyamus kogiae n. sp. is described from a pygmy sperm whale Kogia breviceps (De Blainville, 1838) stranded on Moreton Island, Queensland, Australia. It belongs in the genus Isocyamus because of its white appearance, epaulette-like processes at the anterior dorsum of pereon segment 2, lateral spines on segments 3 and 4, reduced maxilliped, and absence of maxilliped palps, large accessory gills and dentate comb on the dactyle of gnathopod 1. It differs from Isocyamus delphini (Guerin-Meneville, 1836), the only other member of this genus, in that the accessory gills are not equal in length to the main gills, it has no ventral spines, and the dactylus of percopod 1 has a double rather than a single dentate comb. This is the first report of a cyamid from whales of the genus Kogia.

Compositional topography of melon and spermaceti organ lipids in the pygmy sperm whale Kogia breviceps: Implications for echolocation

The forehead of the pygmy sperm whale Kogia breviceps contains a large “melon” of fatty tissue in front of a small, fat-filled, cornucopia-shaped spermaceti organ. This unique anatomical structure may possibly play an acoustical role in the whale's echolocation system, similar to the fatty “melon” sound lens postulated for dolphins. To better understand its function, we have studied the compositional topography of the K. breviceps melon and spermaceti organ lipids. The fatty head tissues of an adult K. breviceps were serially sectioned into 9 transverse slices. Appropriate tissue samples were cut from every other slice, and analyzed for % lipid and lipid class composition. Wax esters and triglycerides were the only major lipids present; their average carbon number in each sample was determined by gas-liquid chromatography (GLC). Our topographical analyses of K. breviceps melon indicate 3 regions of distinctive lipid composition: a fat-poor melon exterior, an “outer melon” of medium fat content having % triglyceride>% wax ester, and a fat-rich “inner melon” having % wax ester>% triclyceride. The spermaceti organ contains a fat-rich core of very high wax-ester content (84 to 99%), surrounded by a fat-poor case. Average carbon numbers of both wax esters and triglycerides were lowest in the inner melon and the spermaceti organ. At the rear of the spermaceti organ lies the “museau de singe”, an apparent sound generator. The lipid topography data plus anatomical and acoustical considerations suggest that the K. breviceps melon/spermaceti organ system may function as an acoustical transducer, directing and refracting sound waves from this source for the purpose of echolocation.