JOURNAL OF CRUSTACEAN BIOLOGY, 21(3): 653–664, 2001 PORCELLIDIUM POOREI, A NEW SPECIES OF PORCELLIDIIDAE (COPEPODA: HARPACTICOIDA) FROM SEAGRASS IN PORT PHILLIP BAY, VICTORIA, AUSTRALIA, AND A REVIEW OF THE FAMILY Genefor K. Walker-Smith Crustacea Laboratory, Museum Victoria, GPO Box 666E, Melbourne, Victoria 3001, Australia, and Zoology Department, The University of Melbourne, Parkville, Victoria 3010, Australia ([email protected]) Downloaded from https://academic.oup.com/jcb/article/21/3/653/2679746 by guest on 28 September 2021 ABSTRACT A new species of Porcellidiidae, Porcellidium poorei, is described from the seagrass beds of Port Phillip Bay, Victoria, Australia. The validity of all genera of Porcellidiidae is discussed, and Mur- ramia, Acutiramus, Kioloaria, Kensakia, and Mucrorostrum are synonymised with Porcellidium. The family diagnosis is expanded. A key to the genera is provided. The family Porcellidiidae Boeck, 1865, with Nomarski interference phase contrast and a drawing comprises 36 species in the genus Porcellid- tube. Scale bars are labelled with lower case letters that ium Claus, 1860, and relatively few others in correspond directly to the figure with the same letter. nine smaller genera (Harris, 1994; Harris and SYSTEMATICS Robertson, 1994; Harris and Iwasaki, 1996b; Porcellidiidae Boeck, 1865 Harris and Iwasaki, 1997). A survey of the Porcellidina Boeck, 1865: 279, 280. harpacticoid copepod fauna of Port Phillip Porcellidiinae.—Brady, 1880: 4, 164. Bay, Victoria, Australia, revealed an unde- Porcellidiidae.—Sars, 1904: 74.—Lang, 1948: 417.— scribed species of Porcellidiidae living on the Harris and Robertson, 1994: 262.—Huys et al., 1996: seagrass Heterozostera tasmanica (Martens 304–306. ex Ascherson) den Hartog. The new species Remarks.—In the past, authorship of the Por- is most similar to taxa in the genus Murramia cellidiidae has been attributed to Sars, 1904 Harris, 1994, but as there are no autapomor- (Lang, 1948; Bodin, 1997) and Brady, 1880 phies defining Murramia, this genus is syn- (Huys and Boxshall, 1991; Huys et al., 1996). onymised with Porcellidium. One of the char- However, in Boeck’s (1865) diagnosis of Por- acter states originally used to define Mur- cellidina, which he established as one of the ramia was the presence of three setae on the eight “Afdelinger” within the family male P2 endopod-3, but this state is also Harpactidae, it is clear that he intended to re- found in Clavigofera Harris and Iwasaki, gard Porcellidium as the type of a new sub- 1996b, Kioloaria Harris, 1994, and Mucro- family (p. 251). Today, “Afdeling”, would be rostrum Harris and Iwasaki, 1997. The va- regarded as a family-group name, probably of lidity of these three genera along with the the rank of subtribe (with suffix -ina). In ac- other genera of Porcellidiidae are discussed. cordance with the Principle of Coordination The family diagnosis of Huys et al. (1996) applied to family-group names (ICZN Art. is emended and a key to the genera is pro- 36.1), Boeck (1865) should be considered as vided. the authority of the family Porcellidiidae as MATERIALS AND METHODS authorship and date remain unchanged at Seagrass, Heterozostera tasmanica, was collected by every rank. hand from shallow (50 cm deep) subtidal, sandy areas along Blairgowrie Beach, Victoria, Australia. Harpacti- Amendments to the Family-Level Diagnosis of coids were washed from the seagrass using fresh water, Huys et al. (1996).—In the most recent diag- then fixed in 4% buffered Formalin. After 48 h, Forma- nosis of the family, Huys et al. (1996) stated lin was washed from the samples, and harpacticoids were that the male P2 endopod-3 has two setae, but stored in 70% ethanol. Harpacticoids were dissected and mounted in glycerol. A Zeiss Stemi SV 11 dissecting mi- this is not always the case. The species of croscope was used and appendages were examined and Kioloaria, Murramia, Clavigofera, Mucro- drawn using an Olympus BX50 compound microscope rostrum, and Porcellidium ravanae Thomp- 653 654 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 3, 2001 son and A. Scott, 1903, possess three setae rostrum and the ‘naviculum’ subgroup (Har- (one serrulate spinose and two plumose) on ris and Robertson, 1994) of Porcellidium. The the male P2 endopod-3. Porcellidium trista- presence of three setae on the male P2 endo- nense Wiborg, 1964, and P. planum Tiemann, pod-3 is also seen in Clavigofera, Mucro- 1977, have four setae (one serrulate spinose and rostrum, Kioloaria, and Porcellidium ra- three plumose) on the male P2 endopod-3. vanae. As there are no unique apomorphies The endopod of the maxillule has six se- uniting the species within Murramia, I con- tae in all genera except Brevifrons Harris, sider it to be a synonym of Porcellidium. 1994, and Mucrorostrum, where only two se- Acutiramus Harris and Robertson, 1994, tae are found. This character state also needs contains five species. Originally the genus to be added to the diagnosis of Porcellidiidae was established on the basis of the rhomboid- Downloaded from https://academic.oup.com/jcb/article/21/3/653/2679746 by guest on 28 September 2021 written by Huys et al. (1996). shaped caudal rami (with oblique terminal border and apical fourth seta) and fifth legs The Validity of Genera.—There are ten nom- (P5) that are long and wrap beyond the cau- inal genera of Porcellidiidae whose validity dal rami. However, the genus Kioloaria also has been questioned by Huys et al. (1996). possesses these character states. Kioloaria In the absence of autapomorphies to distin- was distinguished from Acutiramus because guish them, several of these genera need to the male P2 endopod-3 of Acutiramus has two be synonymised with Porcellidium. All gen- setae, and in Kioloaria it has three. These two era of Porcellidiidae except Porcellidium genera could be united with shared character have been described by Harris and co-work- states being the shape of the caudal rami and ers (see Harris, 1994; Harris and Robertson, the length of P5, but if this was the case Por- 1994; Harris and Iwasaki, 1996b; Harris and cellidium ravanae and Kensakia would also Iwasaki, 1997). Harris and Robertson (1994) have to be included in the group as they also identified seven character states they believed have rhomboid-shaped caudal rami. However, to be diagnostic at the generic level. Only one the fifth limbs (P5) of P. ravanae and Ken- of these character states (the absence of a hya- sakia do not touch each other. Porcellidium line border on the cephalothorax) is an au- ravanae has male P2 endopod-3 with three tapomorphy. One of the character states listed setae and Kensakia has male P2 endopod-3 (male P5 with one terminal seta) does not with two setae. Although the rhomboid- seem to occur in any described Porcellidiidae. shaped caudal rami could be used to unite The three characters most frequently used to these four taxa into a single genus, I don’t be- separate species into new genera were: the lieve there is sufficient evidence to support presence or absence of a ventral blade on the this. There are no other shared character male antennule; the presence of two or three states, and the setation of the caudal rami setae on the male P2 endopod-3; and the max- varies between these taxa. On the caudal rami illule endopod with two or six setae. How- of Acutiramus and Kioloaria setae 2 and 3 are ever, as these character states are shared be- present; seta 3 is missing in P. ravanae, and tween several genera they cannot be used as setae 2 and 3 are missing in Kensakia. I be- evidence for creating new genera. It would lieve Acutiramus, Kioloaria, and Kensakia appear for the most part, that Harris and his are synonyms of Porcellidium. Kensakia was colleagues based the description of new gen- a monotypic genus. era on a unique combination of characters Mucrorostrum is a monotypic genus de- rather than on autapomorphies. fined on the presence of only two setae on the Genera Synonymised with Porcellidium.— maxillule endopod and three setae on the Murramia contains two species. In the orig- male P2 endopod-3. While this is a unique inal diagnosis Harris (1994) characterised the combination of character states, these states genus by the absence of a ventral blade on the are found in other genera. The presence of male antennule and the presence of three se- only two setae on the maxillule endopod is tae on the male P2 endopod-3. While the found in Brevifrons, and the presence of three combination of these character states is setae on the male P2 endopod-3 is found in unique, the character states themselves are Clavigofera, Murramia, and Kioloaria. The not. The ventral blade is absent in Clav- male of Mucrorostrum did exhibit the unusual igofera, Kensakia Harris and Iwasaki, 1997, feature of having a pointed rostrum and a Kushia Harris and Iwasaki, 1996b, Mucro- cephalothorax that was not truncated, but I WALKER-SMITH: A NEW SPECIES OF PORCELLIDIUM FROM AUSTRALIA 655 believe this to be a species-level difference unique to this genus; thus, I see no reason to and thus synonymise the genus with Porcel- synonymise it. lidium. KEY TO THE GENERA OF PORCELLIDIIDAE Other Valid Genera.—Brevifrons is a mono- 1. Cephalothorax with dorsal pits. 2 typic genus characterised by the absence of – Cephalothorax without dorsal pits, instead surface dorsal pits on the cephalothorax and the pres- covered with honeycomb-like pattern of raised ence of a honeycomb-like pattern of raised ridges . Brevifrons Harris, 1994 2. Caudal rami with terminal setae 1–4 evenly spaced, ridges. The cephalothorax of the female is pinnately lanceolate, and identical in size and shape; truncated, and its ventrally directed rostrum striated lateral patch on urosome .