Thenus australiensis, Burton & Davie, 2007

Burton, T. E. & Davie, P. J. F., 2007, A revision of the shovel-nosed lobsters of the genus Thenus (Crustacea: Decapoda: Scyllaridae), with descriptions of three new species, Zootaxa 1429 (1), pp. 1-38 : 19-21

publication ID	https://doi.org/ 10.11646/zootaxa.1429.1.1
publication LSID	lsid:zoobank.org:pub:37D2609C-AD8E-4F89-A7D8-301A861AA058
persistent identifier	https://treatment.plazi.org/id/2B682647-5D17-144C-FF7E-FA4F4783639A
treatment provided by	Felipe
scientific name	Thenus australiensis
status	sp. nov.

Treatment

Thenus australiensis View in CoL sp. nov.

( Fig. 13B View FIGURE 13 , 14 View FIGURE 14 , 17A, D View FIGURE 17 , 18I View FIGURE 18 )

Thenus sp. nov.— Jones, 1990: 265–275.

Thenus orientalis View in CoL .— Wadley & Evans, 1991: 40, 2 figs. — Jones, 1993: 143–155. — Burton, 1995: 53–61; 1996: 499– 506 [not T. orientalis ( Lund, 1793) View in CoL ].

Material examined. Holotype. QM-W1710, female (88.3 x 114.1), Scarness, Torres Strait, 3.9.1949, L.G. Dean.

Paratypes. QM-W22128, male (51.7, 65.3), Eastern Swains Reef , 2.11.1983; QM-W16281, male (43.0, 55.5), 10°06'S 143°12'E, 28 m, 29.9.1988, J. Smith; QM-W22132, male (69.5, 87.4), Torres Strait , 10°04.34’S, 141°50.9’E, trawled 46 m, 1989, Australian Bureau of Rural Resources Survey. NTM-Cr010269, female (42.8 x 53.6), Arafura Sea, N. T., 10°20'S, 134°23'E, trawled, Bag 8706E, 59m, 13.06.1987, NT Fisheries Observers; NTM-Cr010270, male (40.5 x 51.0), Arafura Sea, N. T., 10°19'S, 133°30'E, trawled, Bag 8706H, 80 m, 20.06.1987, NT Fisheries Observers; NTM-Cr010268, male (32.7 x 41.2), Arafura Sea, N. T., 10°20'S, 134°29'E, trawled, Bag 8706A, 59 m, 11.06.1987, NT Fisheries Observers; NTM-Cr008787, male (34.8 x 44.4), N. of Cobourg Peninsula, N. T., 10°43'S, 133°39'E, trawled Taiwanese Stern Trawler THTE, Stn F 087-1, 59 m, 22.03.1987, NT Fisheries Observers; NTM-Cr009741, female (34.8 x 43.8), male (52.7 x 65.3), Arafura Sea , 10°26.45'S, 134°17.87'E, trawled Stn RW 92-48, 62 m, 12.10.1992, R. Williams; NTM- Cr 012289, female (74.2 x 92.8), Arafura Sea, N. T., 10°20'S, 134°23'E, 59 m, trawl, 30.06.1987, NT Fisheries; NTM-Cr012290, 2 males (53.2 x 64.7; 69.5 x 87.4), Arafura Sea, N. T., 14.03.1986, A. Reid & T. Ward; NTM- Cr012280, male (65.2 x 84.5) female (63.6 x 80.0), Arafura Sea, N. T., trawled Taiwanese Stern Trawler BYME, 14.03.1986, A. Reid & T. Ward; NTM-Cr012282, ovig. female (71.9 x 88.3), female (54.0 x 66.6), Arafura Sea, N. T., 10°40'S, 133°50'E, Stn FO 86-3, 60 m, trawled Taiwanese Stern Trawler THCT, 17.04.1986, T. McGuigan; NTM-Cr012283, 2 females (61.8 x 77.4; 67.2 c.l.), data as for NTM-Cr012282. NTM-Cr012284, female (71.8 x 89.3), data as for NTM-Cr012282; NTM-Cr012285, 2 males (68.0 x 85.0; 72.9 x 91.7), data as for NTM-Cr012282; NTM-Cr012286, female (67.5 x 84.0), data as for NTM-Cr012282; NTM-Cr007115, 2 ovig. females (66.2 x 80.0; 67.9 x 83.4), Arafura Sea, N. T., 10°28'S, 134°14'E, Stn FO 86- 6, 60 m, trawled Taiwanese Stern Trawler THTA, April 1986, T. McGuigan & T. Ward; NTM-Cr007167, male (45.2 x 54.9), data as for NTM-Cr007115; NTM-Cr012287, male (59.5 x 75.5), 2 females (68.6 x 84.8; 66.7 x 82.9) Arafura Sea, N. T., 10°48.09'S, 133°06.4'E, trawled, Stn HL 90-10, 60 m, 21.10.1990, H. Larson; NTM- Cr008785, male (61.5 x 80.9), N. of Wessel Is., N. T., 10°28'S, 134°14'E, Stn Aa3, 57 m, W. Houston; NTM- Cr010463, male (79.3 x 98.4), W. of Booby Is., Qld, 10°41.4'S, 141°51.6'E, trawled, 10 m, 29.11.1991, A.J. Bruce & R. Williams; NTM-Cr012288, 4 males (64.8 x 90.2; 71.7 x 90.2; 73.4 x 91; 49.3 x 62.1), juv. (23.2 x 29.4), Indian Ocean, W.A., 20°04'S, 116°37'E, trawled Taiwanese Stern Trawler BYME, Stn 086-8, 10.07.1986, NT Fisheries Observers GoogleMaps .

Diagnosis. Obvious spots or large patches present on some or all segments of legs; outer face of propodus of P2 having upper-most longitudinal groove bearing obvious setae over at least proximal half. Merus of third maxilliped with a small spine proximally on inner ventral margin; inner margin of ischium prominently dentate along entire length. No single morphometric ratio has been isolated that will exclusively identify this species, but only T. australiensis can have ratios that fall outside the following maximum and minimum values: carapace width ( CW 1) less than 1.13 times carapace length (CL); length of antenna 1 (A1L) greater than 0.74 times width (A1W); length of antenna 2 (A2L) greater than 0.67 width (A2W); length of antenna 2 (A2L) greater than 0.37 times carapace length (Ratios 2, 4, 5, 6 in Table 6).

Remarks. Thenus australiensis sp. nov. and T. orientalis Lund , are the most difficult of all the species to distinguish using morphological characters, even though they are clearly distinct genetically. Within Australia we have not found any evidence of T. orientalis being present, although our electrophoretic analyses showed a group of four specimens collected from southeast of Singapore, to be conspecific with T. australiensis . Unfortunately these specimens were subsequently accidently lost, and could not be further investigated. It is thus probable that the distributions of the two species will be found to overlap through Indonesia. The only method of identifying either of the two species, in the absence of genetic data, is through the combination of morphological ratios presented in the key.

The colour of the spotting on the pereiopods of T. australiensis is a relatively uniform dark maroon; in T. orientalis it is highly variable in colour, shape and extent, according to locality. Body colour, and colour of tail-fan and pleopods is variable, apparently being dependent on time since moulting, and is not useful as a diagnostic feature.

Etymology. Named in reference to Australia where it is predominantly found.

Distribution. Northern Australia south to Hervey Bay, southeastern Queensland (pers. comm., A.J. Courtney, Queensland Department of Primary Industries & Fisheries), and Shark Bay, Western Australia. Probably north to Singapore ( Fig. 14 View FIGURE 14 ).