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Pristiophoriformes (Saw sharks) >
Pristiophoridae (Saw sharks)
Etymology: Pliotrema: pleion (Gr.), more; trema (Gr.), hole, referring to six gill slits compared with five in Pristiophorus (See ETYFish); kajae: In honor of Kaja Magdalena Weigmann, the senior author’s daughter, “who had her first contact with chondrichthyan taxonomy when observing with great interest the examination of Pliotrema specimens for the present study”; “Kaja” is also Frisian (Germanic ethnic group from coastal Netherlands and northwest Germany) for “warrior,” referring to the shark’s saw-like rostrum (See ETYFish).
Eponymy: Kaja Magdalena Weigmann (d: 2015) is the daughter of the first author. [...] (Ref. 128868), visit book page.
Môi trường: môi trường / vùng khí hậu / Mức độ sâu / phạm vi phân phối
Sinh thái học
biển gần đáy; mức độ sâu 214 - 320 m (Ref. 122027). Tropical
Western Indian Ocean: off Madagascar and the Mascarene Ridge.
Bộ gần gũi / Khối lượng (Trọng lượng) / Tuổi
Chín muồi sinh dục: Lm ? range ? - ? cm
Max length : 102 cm TL con đực/không giới tính; (Ref. 122027); 143.0 cm TL (female)
Mô tả ngắn gọn
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This species is distinguished by the following characters: barbel origin to anterior nostrils 1.4-2.3 times anterior nostrils to symphysis upper jaw; prenarial length 1.5-1.7 times prebarbel length; preoral length 2.0-2.7 times interdorsal space; pectoral-fin anterior margin 1.2-1.6 times dorsal-caudal space; mouth width 2.8-6.6 times spiracle length; first dorsal fin originates about opposite pectoral-fin free rear tips; lateral trunk dermal denticles tricuspidate, rather flat and imbricated; monospondylous centra 52-57; precaudal diplospondylous centra 48-56; total vertebral centra 151-64. Differs from its congeners, most notably, a rostrum that is clearly constricted between barbel origin and nostrils; it has sharp folds in both upper and lower jaw teeth, as well as a posteriorly notched, teardrop-shaped dorsal fenestra of the precerebral fossa; differs further from P. warreni by barbels that are situated about half way from rostral tip to mouth, with prebarbel length about equidistant from barbel origin to symphysis of upper jaw (vs. barbels about two thirds way from rostral tip to mouth, with prebarbel length about twice distance from barbel origin to symphysis of upper jaw), and with two indistinct, yellowish longitudinal stripes on the dorsal surface (vs. one pronounced yellowish longitudinal
stripe); differs further from P. annae in having generally longer snout, more upper and lower jaw tooth rows, higher total large lateral rostral tooth and ventral rostral spine counts, and a pale to light brown dorsal coloration with two indistinct yellowish stripes, uniform white ventral coloration, and posterior fin margins with narrow white edges (vs. uniform medium to dark brown dorsally without longitudinal stripes, white ventrally but with few indistinct dark blotches on belly, posterior fin margins conspicuously white-edged). Colouration: pale to light brown dorsally with two thin yellowish longitudinal stripes; uniform white ventrally; fins with rather indistinct white posterior fin margins; dorsal rostrum surface with two distinct longitudinal dark stripes, with lateral rostral teeth dark-edged (Ref. 122027).
Cross section: angular.
A female specimen (117 cm TL) was found gravid with about six eggs (based on radiographs). The size at birth estimated to be around 35 cm TL and was based on the four near-term embryos of 31.8-32.9 cm TL (Ref. 122027).
Vòng đời và hành vi giao phối
Chín muồi sinh dục | Sự tái sinh sản | Đẻ trứng | Các trứng | Sự sinh sản | Ấu trùng
Weigmann, S., O. Gon, R.H. Leeney, E. Barrowclift, P. Berggren, N. Jiddawi and A.J. Temple, 2020. Revision of the sixgill sawsharks, genus Pliotrema (Chondrichthyes, Pristiophoriformes), with descriptions of two new species and a redescription of P. warreni Regan. PLoS ONE, 15 (3)[0228791]:1-56. (Ref. 122027)
Tình trạng Sách đỏ IUCN (Ref. 130435: Version 2025-2 (Global))
Mối đe dọa đối với con người
Harmless
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Ước tính dựa trên mô hình
Chỉ số đa dạng phát sinh loài (Tài liệu tham khảo
82804): PD
50 = 0.6270 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00389 (0.00180 - 0.00842), b=3.12 (2.94 - 3.30), in cm total length, based on all LWR estimates for this body shape (Ref.
93245).
Mức dinh dưỡng (Tài liệu tham khảo
69278): 4.1 ±0.6 se; based on size and trophs of closest relatives
Sự dễ bị tổn thương của nghề đánh cá (Ref.
59153): Very high vulnerability (86 of 100).
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![Image of Pliotrema kajae (Kaja\](/images/thumbnails/jpg/tn_Plkaj_f0.jpg "Image of Pliotrema kajae (Kaja\")
