Cossura hutchingsae, Zhadan, 2015

Zhadan, Anna, 2015, Cossuridae (Annelida: Polychaeta: Sedentaria) from Australian and Adjacent Waters: the First Faunistic Survey, Records of the Australian Museum 67 (1), pp. 1-24: 10-11

publication ID

http://doi.org/ 10.3853/j.2201-4349.67.2015.1639

persistent identifier

http://treatment.plazi.org/id/2B16878E-FF8D-D60A-FED0-F9BAC601B1EA

treatment provided by

Carolina

scientific name

Cossura hutchingsae
status

n. sp.

Cossura hutchingsae   n. sp.

Figs 7 View Figure 7 , 8 View Figure 8

Type locality. Australia, New South Wales, Hawkesbury River.

Type material. Holotype anterior fragment with 18 chaetigers, all thoracic, 3 mm long, 0.64 mm wide, New South Wales, Hawkesbury River, 200 m south of eastern end of Spectacle Island , 8­V­84 3­3­ 3 W. 43372.  

Paratypes, 9 specimens, Victoria, mouth of Yarra River, Hobsons Bay, Port Phillip Bay (37°50'29"S 144°53'52"E), 23 Jun. 1975, coll. Marine Studies Group, W. GoogleMaps   16338; 1 specimen, New South Wales, Hawkesbury River, 200 m south-east of Croppy Point (33°33'S 151°17'E), 21-VIII-84 2­3­3, W.42865 GoogleMaps   .

Additional material examined. New South Wales. 1 specimen, Hawkesbury River, between Juno Head and Hungry Beach (33°34'S 151°16'E), mid-stream, 07 Aug. 1981, 1-3-2, depth 10 m, coll.A. R. Jones,A. Murray, W. 43417 GoogleMaps   ; 1 specimen, Hawkesbury River, 200 m south of eastern end of Spectacle Island (33°32'30"S 151°13'30"E), 3-3-2, 05 Aug. 1984, depth 5 m, Smith-McIntyre grab, sandy mud, coll. A. R. Jones, A. Murray, W. 43369 GoogleMaps   ; 1 specimen, 3242 Bega River, Tathra 2008, west of Hancock Bridge (36°41'54"S 149°58'15" E), depth 5.9 m, 3 April 2008, coll. K.B. Attwood, S.J. Keable, A. Murray GoogleMaps   , R. T. Springthorpe, RV Baragula, van Veen grab, sandy mud, W.43346   ; 1 specimen, west of La Perouse, Botany Bay (33°59'24"S 151°12'48"E), 10 Mar. 1977, depth 13 m, coll. State Pollution Control Commission GoogleMaps   , st.99, W.13652; 1 specimen, Botany Bay, west of La Perouse (33°59'18" S 151°12'38"E), depth 19.2 m, 02 Feb. 1977, col. State Pollution Control Commission GoogleMaps   , st.81, W.13653.— Queensland. 1 specimen, Calliope River, Gladstone (23°51'S 151°10'E), Dec. 1976, coll. P.Saenger GoogleMaps   , W.13224.

Diagnosis. Prostomium trapezium-shaped with wide round anterior margin. 17–21 thoracic chaetigers; border between body regions unclear. Branchial filament arising from border between chaetigers 2 and 3. Anterior margins of thoracic segmental borders dorsally drawn forward. Thoracic neuropodia with 2–3 very thick bent chaetae with long thread-like distal tips; other chaetae in thorax and abdomen capillary.

Description. All specimens incomplete, with 18–50 segments, 4–12 mm in length, 0.4–0.8 mm in width. Anterior region (thorax) with 17–21 chaetigers; border between regions unclear ( Figs 7A View Figure 7 , 8A,B View Figure 8 ). In specimen with gametes in body cavity they start from chaetiger 24. Thoracic chaetigers have glandular inflations on their lateral and dorsal sides, mid-dorsally dorsal groove located between them. Anterior margins of segmental borders dorsally drawn forward, to the base of branchial filament ( Figs 7B,E View Figure 7 , 8A View Figure 8 ). Segments becoming longer in the abdominal region.

Prostomium trapezium­shaped, flattened dorsoventrally, anterior margin from semi-circular to almost straight ( Figs 7B,E View Figure 7 , 8C View Figure 8 ). Posterior ring as long as peristomium; border with peristomium not always clear; prostomial furrow developed to various degrees; in some specimens additional furrows in prostomium and peristomium.

Branchial filament arising from border between chaetigers 2 and 3 ( Figs 7B,D–F View Figure 7 , 8C,D View Figure 8 ), in some cases may be impression of its attachment from anterior border of chaetiger 3. Nuchal organs not seen.

Chaetiger 1 with uniramous parapodia, all next segments bearing biramous parapodia. All chaetae hirsute capillaries with smooth shafts; arranged in two indistinct rows. Thicker chaetae are located in anterior row, thinner ones in posterior ( Fig. 7D,F,G View Figure 7 ). First chaetiger bears four or five chaetae, in next segments notopodia bear 5 chaetae in anterior row and 4–5 in posterior, neuropodia bear 2–3 very thick (14–16.5 μm in thickness) bent chaetae with long thread­like distal tips in anterior row and 4–5 capillaries in posterior ( Figs 7F,G View Figure 7 , 8E,F View Figure 8 ). After chaetiger 10–13 these thick chaetae replaced with normal capillary chaetae. Chaetae in abdomen thinner and more numerous, 12–14 chaetae per ramus ( Fig. 8G View Figure 8 ).

Gametes in body cavity were observed in one specimen from Victoria (W.16338) ( Fig. 7A View Figure 7 ).

Posterior end unknown.

Etymology. This species has been named in honour of Pat Hutchings from Australian Museum, in recognition of her great contribution to the knowledge of polychaetes and Australian marine biota.

Remarks. Thickened chaetae in thoracic chaetigers are described also for Cossura heterochaeta   , C. rostrata Fauchald, 1972   , and C. ginesi   . Cossura ginesi   differs by the shape of prostomium with anterior extension. Cossura heterochaeta   and C. rostrata   have a conical prostomium (round to obtuse in C. hutchingsae   n.sp.), and there are two types of anterior thickened chaetae—with arista and without it—in C. heterochaeta   , whereas in our worms they are uniform having aristas. Besides, C. hutchingsae   n.sp. has more anterior segments (17–21 instead of 12–14 in C. heterochaeta   ). The most characteristic features of this new species are the inflated pads in thorax and the segmental borders drawn forward dorsally, giving it a peculiar appearance.

R

Departamento de Geologia, Universidad de Chile

T

Tavera, Department of Geology and Geophysics

RV

Collection of Leptospira Strains

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Family

Cossuridae

Genus

Cossura