Leopard epaulette shark

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Leopard epaulette shark
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Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Orectolobiformes
Family: Hemiscylliidae
Genus: Hemiscyllium
Species:
H. michaeli
Binomial name
Hemiscyllium michaeli
Leopard Epaulette Shark Range.png
Known range of the leopard epaulette shark (in blue)

The leopard epaulette shark (Hemiscyllium michaeli), also known as the Milne Bay epaulette shark and Michael's epaulette shark, is a species of bamboo shark in the genus Hemiscyllium . [2] It is a tropical shark known from the shallow ocean in the Milne Bay region of eastern Papua New Guinea. [3] The epaulette sharks of this region have long been confused with the Indonesian speckled carpetshark (H. freycineti), and it was only in 2010 that H. michaeli was described as a separate species by Gerald R. Allen and Christine L. Dudgeon. [3] It can reach a maximum length of 82 cm (32.3 in). [4] Confusingly, some books with illustrations and photos labelled as H. freycineti actually show H. michaeli. [5]

Contents

Etymology

The leopard epaulette shark was originally confused with the Indonesian speckled carpetshark, until photographer and aquarist Scott W. Michael recognized that they were distinct species and brought this to the attention of researchers. [6] The shark was subsequently named in honour of Michael, and for his contributions of information and photographs to Allen's research on Indo-Pacific fishes. [7] Another common name for this species is the Milne Bay epaulette shark. In the paper by Allen and Dudgeon, [3] it is said that the two populations are geographically separated by approximately 1,200 km.

Distribution and habitat

The range of the leopard epaulette shark is confined to eastern Papua New Guinea, with most observations and collecting records from the Milne Bay province. It has also been collected at Oro Province in the vicinity of Harvey Bay. It is unclear if the distribution of the leopard epaulette shark extends along the Papua New Guinea mainland northwest towards Bootless Inlet, nor where its distribution abuts that of the Papuan epaulette shark (Hemiscyllium hallstromi). The presence of Hemiscyllium in the Huon Gulf is unknown; presumably the large estuarine area around Lae may provide sufficient habitat disjunction to separate H. michaeli and the Hooded epaulette shark (Hemiscyllium strahani). [6]

The leopard epaulette shark is found in shallow water to a maximum depth of 20 m (66 ft) in fringing and patch tropical coral reefs, rocky outcrops, tidal pools, and seagrass beds. [8]

Description

Leopard epaulette sharks are named for the brilliant leopard-like pattern covering their body. Leopard Epaulette Shark.jpg
Leopard epaulette sharks are named for the brilliant leopard-like pattern covering their body.

The leopard epaulette shark has an elongated body, over half of which is comprised by the slender caudal peduncle. Its dorsal fin and anal fin is set very far back on an extremely long, thick tail. It differs from other Hemiscyllium species by having a shorter first dorsal fin and anal fin base, and lower anal fin.

The eyes are oval in shape and elevated, with a large spiracle below each. The five pairs of gill slits are small, with the fourth and fifth very close together. [9]

A juvenile of this species, showing the stark difference present between juveniles and adults Leopard Epaulette Shark juvenile.webp
A juvenile of this species, showing the stark difference present between juveniles and adults

This species of Hemiscyllium is characterized by its unique colour pattern, which includes dense leopard-like spotting covering the body and a noticeable large black ocellated spot behind the head. It is similar in appearance to H. freycineti but can be differentiated by having denser and more leopard-like dark spots, a larger and well-developed post-cephalic ocellus, and a greater number of spots on the snout's dorsal surface. The overall coloration is whitish to pale grey-brown, with a dense network of leopard-like brown spots on the head, body, and fins. There is a distinct white-rimmed dark-brown mark behind the head, roughly aligned with the posterior edge of the pectoral fin. Sometimes, a series of about 9-10 bars may be faintly visible on the sides and more prominent on the tail. [6] The dorsal fins feature 2–3 prominent saddle-like markings along their edges. Subadults of this species lack leopard-like spots and instead have solid spots on their head, body, and fins. [6] Juveniles of this species display a predominantly white coloration with a number of dark brown bars, including on the head and caudal fin. There are a few small brown spots on the head and anterior body, situated within pale areas. Despite being partially merged with the second dark bar, the distinct large ocellus characteristic of the species is still evident. [6] [8]

The snout is short and rounded, with the nares placed almost at the tip along with a pair of tiny barbels; there are grooves running from the nares to the mouth. There are possibly 26–35 tooth rows in the upper jaw and 21–32 tooth rows in the lower jaw. The teeth are small, with broad bases and triangular cusps.

Leopard epaulette sharks are typically 60–78 cm (23.6–30.7 in) long; the maximum reported length is at least 82 cm (32.3 in). [4]

Biology and ecology

Although this species is critically understudied, we still know that as an adaptation for navigating its complex reef environment, like other members of the Hemiscyllium genus, the leopard epaulette shark moves by seemingly walking, bending its body from side-to-side and pushing off of the substrate with its paddle-shaped pectoral and pelvic fins. Its gait is similar to that of salamanders, an example of convergent evolution. The shark is capable of swimming, but often prefers to walk along the sandy or coral bottom even when the water is deep enough to allow it to swim freely. The cartilaginous supports of the shark's paired fins are reduced and separated when compared to other sharks, allowing them to be rotated for use as limbs. [10] This mode of locomotion even enables the shark to crawl out of the water to access isolated tidal pools. [11] The gait of the epaulette shark is convergently similar to those of tetrapods such as salamanders, suggesting that the movements needed for walking on land may predate, and facilitated the evolution of, the first terrestrial vertebrates. [12] Leopard epaulette sharks are largely nocturnal and are most active in low water. They often hide inside or below coral heads, though it is enough for the head to be covered even if the rest of the body is exposed. [9] Sometimes they perch in the open on sandy flats or atop reefs facing into the current, a form of orientation known as rheotaxis that may improve respiration or predator awareness. [13]

The first-ever footage of a leopard epaulette shark leaving the water and walking on land was captured by wildlife biologist and rare species expert Forrest Galante.

The footage was shown as part of a documentary called Island of the Walking Sharks , co-hosted by fellow marine biologist Vicky Vásquez. The documentary was released as part of Shark Week 2022. The footage was the first time in history one of the Papuan species of Epaulette had been recorded and filmed walking out of the water. The documentary further focused on the other two Papuan epaulettes, the Papuan epaulette shark and the hooded epaulette shark.

Comparisons

Due to the similarity of colour pattern and a misunderstanding of the geographic range, this species was long confused with H. freycineti. Due to sub-adults and some adults not developing the full leopard pattern, the species can also be confused with H. hallstromi.

In a blog post, Scott W. Michael postulated that "two new species" of the leopard epaulette shark could be present "off the coast of Milne Bay Province." He compared an observation by Rob van der Loos off a resort in Milne Bay with an observation he had made 100 km southeast. [5]

He suggested that the differences in coloration, particularly the epaulette over the pectoral fin, could give rise to the possibility of there being two epaulette species off the coast of Milne Bay Province, and speculates that the observed differences in colouration could maybe be attributed to the age of the shark specimen. He further added that while colour differences may not always be a reliable indicator for distinguishing fish species, it appears to be a consistent characteristic for differentiating members within the Hemiscyllium genus. He further proposed that further investigation involving shark DNA analysis by Dr. Allen and the passage of time will provide more conclusive information. [5]

Human interactions

Leopard epaulette sharks are harmless to humans, though if handled they may nip their captors. Due to their restricted range, they experience habitat degradation, and capture for food in artisanal fisheries. They could possibly enter the aquarium trade. [8]

Related Research Articles

<span class="mw-page-title-main">Carpet shark</span> Order of sharks

Carpet sharks are sharks classified in the order Orectolobiformes. Sometimes the common name "carpet shark" is used interchangeably with "wobbegong", which is the common name of sharks in the family Orectolobidae. Carpet sharks have five gill slits, two spineless dorsal fins, and a small mouth that does not extend past the eyes. Many species have barbels.

<span class="mw-page-title-main">Zebra shark</span> Species of carpet sharks

The zebra shark is a species of carpet shark and the sole member of the family Stegostomatidae. It is found throughout the tropical Indo-Pacific, frequenting coral reefs and sandy flats to a depth of 62 m (203 ft). Adult zebra sharks are distinctive in appearance, with five longitudinal ridges on a cylindrical body, a low caudal fin comprising nearly half the total length, and usually a pattern of dark spots on a pale background. Young zebra sharks under 50–90 cm (20–35 in) long have a completely different pattern, consisting of light vertical stripes on a brown background, and lack the ridges. This species attains a length of 2.5 m (8.2 ft).

<span class="mw-page-title-main">Tasselled wobbegong</span> Species of shark

The tasselled wobbegong is a species of carpet shark in the family Orectolobidae and the only member of the genus Eucrossorhinus. It inhabits shallow coral reefs off northern Australia, New Guinea, and adjacent islands. Reaching 1.8 m (5.9 ft) in length, this species has a broad and flattened body and head. Its most distinctive trait is a fringe of branching dermal flaps around its head, which extends onto its chin. The fringe, along with its complex color pattern of small blotches and reticulations, enable it to camouflage itself against the reef environment.

<span class="mw-page-title-main">Hemiscylliidae</span> Family of sharks

The Hemiscylliidae are a family of sharks in the order Orectolobiformes, commonly known as longtail carpet sharks and sometimes as bamboo sharks. They are found in shallow waters of the tropical Indo-Pacific.

<span class="mw-page-title-main">Bluegrey carpetshark</span> Species of shark

The bluegrey carpetshark or Colclough's shark, is an uncommon species of carpet shark endemic to shallow inshore waters off northeastern Australia. It is one of the two extant members of the family Brachaeluridae. The bluegrey carpetshark has a stocky body with a wide, slightly flattened head, dorsally placed eyes, and a pair of long barbels with posterior skin flaps. It has large pectoral fins, two dorsal fins of unequal size placed far back on the body, and a sizeable space between the anal fin and the base of the caudal fin. Growing to 76 cm (30 in) long, this species has a black-and-white colour pattern as a juvenile, which largely fades with age such as that adults are brownish.

<span class="mw-page-title-main">Coral catshark</span> Species of shark

The coral catshark is a species of catshark in the family Scyliorhinidae. It is common on shallow coral reefs across the Indo-West Pacific, from Pakistan to New Guinea. Reaching up to 70 cm (28 in) in length, the coral catshark has an extremely slender body, a short head and tail, and two dorsal fins that are angled backwards. It can be identified by the numerous black and white spots on its back, sides, and fins, which often merge to form horizontal bars. Furthermore, adult males have distinctively long and thin claspers.

<span class="mw-page-title-main">Epaulette shark</span> Species of longtailed carpet shark

The epaulette shark is a species of longtailed carpet shark of the family Hemiscylliidae, found in shallow, tropical waters off Australia and New Guinea. The common name of this shark comes from the very large, white-margined black spot behind each pectoral fin, which are reminiscent of military epaulettes. A small species usually under 1 m (3.3 ft) long, the epaulette shark has a slender body with a short head and broad, paddle-shaped paired fins. The caudal peduncle comprises over half the shark's length. Adults are light brown above, with scattered darker spots and indistinct saddles.

<span class="mw-page-title-main">Arabian carpetshark</span> Species of shark

The Arabian carpetshark is a species of carpet shark in the family Hemiscylliidae, inhabiting coral reefs and other shallow coastal habitats from the Persian Gulf to India. Reaching 78 cm (31 in) long, this shark is characterized by a slender, plain brown body, and by two dorsal fins with straight trailing margins and the second smaller but longer-based than the first. The Arabian carpetshark feeds on bony fishes and invertebrates. Reproduction is oviparous with an annual cycle; females deposit egg capsules four at a time and the young hatch after 70–80 days. This small shark is often captured as bycatch but rarely used by humans. It has been assessed as Near Threatened by the International Union for Conservation of Nature (IUCN), as there is increasing fishing pressure and habitat degradation within its range. It does well in aquariums and has been bred in captivity.

<span class="mw-page-title-main">Indonesian speckled carpetshark</span> Species of shark

The Indonesian speckled carpetshark, Hemiscyllium freycineti, is a species of bamboo shark in the family Hemiscylliidae. It is found in the shallow ocean around the Raja Ampat Islands in West Papua, Indonesia, but was formerly believed to be more widespread. This was due to confusion with H. michaeli, a species described from eastern Papua New Guinea in 2010. Compared to that species, the spots on H. freycineti are smaller, more rounded or slightly elongated in shape, and tend to darken at regular intervals forming 8-9 vertical bars on the body and tail. Furthermore, the large black spot behind the pectoral fin is more clearly defined in H. michaeli than in H. freycineti. Confusingly, some books with illustrations and photos labelled as H. freycineti actually show H. michaeli.

<span class="mw-page-title-main">Papuan epaulette shark</span> Species of shark

The Papuan epaulette shark, Hemiscyllium hallstromi, is a bamboo shark in the family Hemiscylliidae found around southern Papua New Guinea, between latitudes 7° S and 10° S, and longitude 144° E and 146° E. Its length is up to 75 cm.

<span class="mw-page-title-main">Hooded carpetshark</span> Species of shark

The hooded carpetshark is a bamboo shark in the family Hemiscylliidae found around Papua New Guinea, between latitudes 5° S and 10° S, and longitude 144° E and 153° E. Its length is up to 75 cm. Like other longtailed carpetsharks, it can use its strong pectoral fins to walk on land for a short period of time. The hooded carpetshark is heavily wanted in the aquarium trade, the result is making this shark endangered.

<span class="mw-page-title-main">Speckled carpetshark</span> Species of shark

The speckled carpetshark, Hemiscyllium trispeculare, is a bamboo shark in the family Hemiscylliidae found around north and west Australia between latitudes 8° S and 22° S, and longitude 114° E and 152° E. Its length is up to 79 cm, and it inhabits shallow coral reefs. It is also kept in aquaria. The speckled carpetshark is closely related to the epaulette shark

<i>Hemiscyllium</i> Genus of sharks

Hemiscyllium is a genus of sharks in the family Hemiscylliidae.

<i>Hemiscyllium galei</i> Species of shark

Hemiscyllium galei, the Cenderawasih epaulette shark, is a species of bamboo shark in the family Hemiscylliidae. Together with H. henryi, it was only scientifically described in 2008 by Gerald R. Allen and Mark V. Erdmann. At present, H. galei is only known from depths of 2 to 4 metres at reefs in the Cenderawasih Bay in West Papua, Indonesia. The largest known specimen was 56.8 centimetres (22.4 in) long. It can be separated from its relatives by the combination of seven relatively large dark spots along the side of the body, white markings on the edge of its dark dorsal saddles and other scattered white spots on the upper side.

The Triton epaulette shark is a species of bamboo shark in the genus Hemiscyllium, that is composed of nine morphologically similar, yet distinct, sharks that are geographically restricted to New Guinea and northern Australia. Hemiscylliidae are small nocturnal sharks aptly named "walking sharks" who exhibit a "crawling" movement while foraging on the ocean floor for fish and benthic invertebrates.

<i>Hemiscyllium halmahera</i> Species of shark

Hemiscyllium halmahera, or the Halmahera epaulette shark, is a species of bamboo shark from Indonesia. This species is described from two specimens collected near Ternate island in 2013, off the coast of larger Halmahera island. This species is most similar to Hemiscyllium galei, found in West Papua, but looks strikingly different in its pattern of spots. While H. galei has seven large, dark spots on each side of its body, H. halmahera has a brown color with clusters of brown or white spots in polygon configurations all over its body. These small sharks are like other bamboo sharks, in that they use their pectoral fins to "walk" along the ocean floor.

Pomacentrus aurifrons, the yellowhead damselfish, is a species of ray-finned fish from the family Pomacentridae, the damselfishes and clownfishes. It is found in the western Pacific Ocean.

<span class="mw-page-title-main">Latent sling-jaw wrasse</span> Species of fish

Latent sling-jaw wrasse is a species of ray-finned fish from the wrasse Family Labridae which is associated with reefs in the south-western Pacific Ocean.

<i>Parascorpaena aurita</i> Species of fish

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References

  1. VanderWright, W.J.; Allen, G.R.; Derrick, D.; Dudgeon, C.; Erdmann, M.V.; Sianipar, A. (2021). "Hemiscyllium michaeli". IUCN Red List of Threatened Species . 2021: e.T195438A198886371. doi: 10.2305/IUCN.UK.2021-2.RLTS.T195438A198886371.en . Retrieved 18 November 2021.
  2. Hemiscyllium michaeli at www.fishbase.org.
  3. 1 2 3 Gerald R. Allen and Christine L. Dudgeon (2010): Hemiscyllium michaeli, a new species of Bamboo Shark (Hemiscyllidae) from Papua New Guinea, pp. 19-30. Aqua International Journal of Ichthyology 16 (1)
  4. 1 2 White, William T.; Baje, Leontine; Sabub, Benthly; Appleyard, Sharon A.; Pogonoski, John J.; Mana, Ralph R. (2017). Sharks and Rays of Papua New Guinea (ACIAR Monograph No. 189 ed.). Canberra: Australian Centre for International Agricultural Research. pp. 74–75. ISBN   978-1-925746-03-7.
  5. 1 2 3 Michael, Scott (2008-05-16). "Gobies to Grizzlies: WILL THE REAL HEMISCYLLIUM FREYCINETI PLEASE STAND UP?". Gobies to Grizzlies. Retrieved 2023-06-21.
  6. 1 2 3 4 5 Allen, Gerald R.; Erdmann, Mark V.; White, William T.; Fahmi; Dudgeon, Christine L. (2016-11-02). "Review Of The Bamboo Shark Genus Hemiscyllium (Orectolobiformes: Hemiscyllidae)". Journal of the Ocean Science Foundation. 23: 81–83. doi:10.5281/ZENODO.164197.
  7. Christopher Scharpf & Kenneth J. Lazara (22 September 2018). "Order ORECTOLOBIFORMES (Carpet Sharks)". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 7 March 2022.
  8. 1 2 3 Ebert, David A.; Dando, Marc; Fowler, Sarah L. (2021). Sharks of the world: a complete guide. New Jersey: Princeton University Press. ISBN   978-0-691-20599-1.
  9. 1 2 Compagno, L.J.V. (2002). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date (Volume 2). Rome: Food and Agriculture Organization. pp. 181–182. ISBN   978-92-5-104543-5.
  10. Goto, T.; Nishida, K. & Nakaya, K. (Sep 1999). "Internal morphology and function of paired fins in the epaulette shark, Hemiscyllium ocellatum". Ichthyological Research. 46 (3): 281–287. doi:10.1007/BF02678514. S2CID   1339099.
  11. Martin, R.A. Why Do Sharks Expose Their Dorsal Fins? Archived 2009-10-03 at the Wayback Machine ReefQuest Centre for Shark Research. Retrieved on October 4, 2009.
  12. Martin, R.A. Intertidal Zone: Epaulette Shark Archived 2008-10-06 at the Wayback Machine . ReefQuest Centre for Shark Research. Retrieved on May 14, 2009.
  13. Peach, M.B. (2002). "Rheotaxis by epaulette sharks, Hemiscyllium ocellatum (Chondrichthyes: Hemiscylliidae), on a coral reef flat". Australian Journal of Zoology. 50 (4): 407–414. doi:10.1071/ZO01081.