CARUKIIDAE Bentlage et al. 2010

Bentlage, Bastian & Lewis, Cheryl, 2012, An illustrated key and synopsis of the families and genera of carybdeid box jellyfishes (Cnidaria: Cubozoa: Carybdeida), with emphasis on the “ Irukandji family ” (Carukiidae), Journal of Natural History (J. Nat. Hist.) 46 (41 - 42), pp. 2595-2620 : 2603-2605

Family CARUKIIDAE Bentlage et al. 2010

1. Rhopaliar horns straight and narrow ( Figure 4A ); two broad, usually unbranched velarial canals per octant ( Figure 4B ); perradial lappet warts lacking ( Figure 4B ) or lappets with single wart on each side; tentacles with “neckerchiefs” ( Figure 4C ).................. Genus Carukia ( Figure 4A–C ) Rhopaliar horns and velarial canals different from above; tentacles without “neckerchiefs”.......................................................... 2

2. Rhopaliar horns short, broad, blunt or with pointed tips ( Figure 4D ); three to four unbranched or mildly branched velarial canals that originate from one root, somewhat palmate ( Figure 4E ); two rows of one to four perradial lappet warts ( Figure 4E )..................... Genus Malo ( Figures 2B , 3G , 4D, E ) Velarial canals heavily branching with or without lateral diverticula; two rows with more than three or four perradial lappet warts....................... 3

3. Rhopaliar horns short, broad, curved (devil-horn shaped; Figure 4F ); numerous laminar branching velarial canals without diverticula ( Figure 4G ); two rows of three to six perradial warts per row (usually five; Figure 4G ).................................................... Genus Gerongia ( Figure 4F, G ) Rhopaliar horns “rabbit-ear” like ( Figure 4H, I ); numerous heavily branching velarial canals with lateral diverticula ( Figure 4J ); two rows of numerous perradial warts plus scattered warts ( Figure 4J )....................................................................... Genus Morbakka ( Figure 4H–J )

Carukia Southcott, 1967 (refer to Southcott 1967; Gershwin 2005b). Type species: Carukia barnesi Southcott, 1967 , by original designation. Species: C. barnesi Southcott, 1967 , C. shinju Gershwin, 2005 b .

Gerongia Gershwin and Alderslade, 2005 (refer to Gershwin and Alderslade 2005). Type species: Gerongia rifkinae Gershwin and Alderslade, 2005 , by original designation. Species: G. rifkinae Gershwin and Alderslade, 2005 .

Malo Gershwin, 2005b (refer to Gershwin 2005b, 2007; see species descriptions below). Type species: Malo kingi Gerswhin, 2007 , by original designation. Species: M. kingi Gerswhin, 2007 , M. filipina sp. nov. described herein, M. maxima Gershwin, 2005b .

Morbakka Gershwin, 2008 (refer to Gershwin 2008; see species descriptions below). Type species: Morbakka fenneri Gershwin, 2008 , by original designation. Species: M. fenneri Gershwin, 2008 , M. virulenta ( Kishinouye, 1910) .

Geographic distribution of the family

Indo-Pacific; tropical to (warm) temperate; neritic, and possibly oceanic.

Remarks

Carukiidae contains species of box jellyfish first identified as causing a serious envenomation syndrome called Irukandji syndrome. Before Bentlage et al. (2010), the genera contained now in Carukiidae were classified in the Tamoyidae alongside Tamoya (see below; Gershwin and Alderslade 2005; Daly et al. 2007). At present, Carukiidae are only known from the Indo-Pacific ranging from New South Wales in Australia to Honshu in Japan on the north–south axis. Much less is known about the eastern and western limits of the distribution of Carukiidae . Gershwin and Alderslade (2005) provide a tabular comparison of the carukiid genera (then called Tamoyidae ). We illustrated the main characters to distinguish between the genera of Carukiidae in Figure 4 .

The close relationship and the intergrading and difficult-to-interpret characters of Malo , Morbakka and Gerongia (see Gershwin 2005b, 2008; Gershwin and Alderslade 2005; Bentlage et al. 2010), suggest that these three genus names should be synonymized. Among the problematic characters invoked to differentiate these genera was the number of eyes per pedalium ( Gershwin and Alderslade 2005); however, the eye pigment may fade in fixative and lead to inaccurate counts (Bentlage 2010). In our opinion, differences in the shape of the rhopaliar horns, the branching patterns of the velarial canals, and the number and arrangement of nematocyst warts on the perradial lappets are the most reliable morphological characters to distinguish the genera of Carukiidae . In addition, nematocyst wart counts and patterns on the velarium may be distinct among carukiid genera. In Carukia , velarial warts are either absent or present as a single wart in each octant. Malo possesses two to four warts per octant, whereas Morbakka possesses six to eight warts, even though Gershwin (2008) notes that some specimens of M. fenneri lack warts altogether. Our review of the literature indicates that velarial warts might be absent in Gerongia . Velarial warts were neither mentioned in the literature nor visible in any of the published images; however, living specimens may possess velarial warts that were lost in preserved material through abrasion. Additionally, medusae of each genus of Carukiidae seem to differ in size, albeit sizes may overlap. Maximum bell heights of Carukia range from 1 to 2 cm, of Malo from 2 to 5 cm, of Gerongia about 6 cm, and of Morbakka from 10 to 15 cm ( Gershwin and Alderslade 2005; unpublished observations).

Records of Carukiidae species are rare and are mostly limited to the Australian continent. To add to the knowledge of the diversity and distribution of Carukiidae , we describe a new species of Malo from the Philippines, redescribe Morbakka virulenta from Japan, and document the discovery of an unknown/unidentified species of Morbakka from the Philippines. Morbakka virulenta was originally described as Tamoya virulenta by Kishinouye (1910). The species, however, lacks the vertical gastric phacellae characteristic of Tamoya (see Collins et al. 2011), but possesses the distinctive “rabbit-ear”-shaped rhopaliar horns of Morbakka . The original type material appears lost and our inquiries among Japanese colleagues did not reveal where potential type specimens may be located. It is likely that the material investigated for the original description of M. virulenta was lost around the time of World War II. Morbakka virulenta is very similar in appearance to M. fenneri from Australia. To aid future taxonomic studies, we designate a neotype for M. virulenta and provide a description of the material examined in another section of the manuscript below.

Figures

Figure 2. Representative species of box jellyfish from each family of Carybdeida (A–E) and one from Chirodropida (F). Note that the chirodropid possesses multiple tentacles per pedalium (F) whereas the carybdeid species possess only a single tentacle per pedalium (A–E). (A) Tamoya ohboya (Tamoyidae; image courtesy of Tim Lowry), (B) Malo kingi (Carukiidae), (C) male and female of Copula sivickisi coupling during courtship (Tripedaliidae; image courtesy of Alvaro Migotto), (D) Carybdea branchi (Carybdeidae; image courtesy of Brent Viljoen), (E) Alatina sp. (Alatinidae), (F) Chiropsalmus quadrumanus (Chiropsalmidae).sb: swimming bell, pe: pedalium, te: tentacle.

Figure 3. Key characters for identification of the Carybdeida: (A) location of taxonomic characters (Carybdea brevipedalia; image courtesy of Alvaro Migotto), (B) T-shaped rhopaliar niche ostium; note the three scales covering the niche, thus leaving a T-shaped ostium, (C) heartshaped rhopaliar niche ostium; niche ostium with only one upper covering scale, (D) key-hole shaped rhopaliar niche ostium in Copula sivickisi, (E) frown-shaped rhopaliar niche ostium in Tripedalia, (F) frown-shaped rhopaliar niche ostium in Tamoya, (G) frown-shaped rhopaliar niche ostium with rhopaliar horns in Malo, (H, I) vertical gastric phacellae in the stomach of Tamoya, (J) multiple pedalia on each corner of the swimming bell in Tripedalia, (K) crescentric gastric phacellae in Alatina (apical view). cs: covering scale, ma: manubrium, ph: gastric phacellae (comprises gastric cirri) in the stomach cavity, pc: pedalial canal, pcb: pedalial canal bend, pe: pedalium, rh: rhopalium, rn: rhopaliar niche that opens on the exumbrellar side of the bell with the rhopaliar niche ostium, rno: rhopaliar niche ostium, rho: rhopaliar horn, sto: stomach, te: tentacle, ve: velarium, vec: velarial canal.

Figure 4. Characters distinguishing the genera of Carukiidae. The location of the characters illustrated in (A–J) are indicated on the specimen in the upper left hand corner. The rhopaliar niche ostium is always horizontally oriented and more or less oval in the Carukiidae; however, its shape may vary among specimens. Carukia: (A) rhopaliar niche with horns, (B) velarium, (C) tentacle with “neckerchiefs”; Malo: (D) rhopaliar niche with horns, (E) velarium; Gerongia: (F) rhopaliar niche with horns, (G) velarium; Morbakka: (H, I) differences of rhopaliar niche and horns between M. fenneri (H) and M. virulenta (I), in both cases the rhopaliar horns are “rabbit-ear” shaped but the angle and breadth of the horns vary, (J) velarium. nc: “neckerchief”, nw: nematocyst wart, pl: perradial lappet, rn: rhopaliar niche, rno: rhopaliar niche ostium, rho: rhopaliar horn, ve: velarium, vec: velarial canal.