Jassaslatteryi Conlan, 1990

Conlan, Kathleen E., Desiderato, Andrea & Beermann, Jan, 2021, Jassa (Crustacea: Amphipoda): a new morphological and molecular assessment of the genus, Zootaxa 4939 (1), pp. 1-191 : 54-60

Jassaslatteryi Conlan, 1990

( Table 10 , Figs 22–27 )

J. cadetta Krapp etal., 2008, pp. 337–345 , figs. 4–7

J. trinacriae Krapp etal., 2010, pp. 85–100 , figs. 5–7

Diagnosis.

Both sexes:

Mandibular palp: article 2, dorsal margin without a fringe of setae.

Maxilla 1: without a seta or setal cluster at the base of the palp article 1.

Gnathopod 1: basis, anterolateral margin without a row of short setae along its length; carpus with a single or group of long setae at the anterodistal junction of the propodus, (seta(e) Ẑ50% the length of the anterior margin length and slightly medial).

Gnathopod 2: basis with a row of setae along the anterolateral margin (length of most setae <40% of the basis width); carpus and propodus, setae on the anterior margin short and simple (setal length <basis width).

Pereopods 5–7: propodus not expanded anteriorly.

Uropod 1: ventral peduncular spinous process underlying about ¼ of the longest ramus.

Uropod 3: inner ramus without spines mid-dorsally (with only the single apical spine).

Telson: tip without apical setae (only the usual short setae at each dorsolateral cusp).

Thumbed male:

Antenna 2: large individuals with plumose setae on the flagellum and peduncular article 5.

Gnathopod 2: propodus, palmar defining spines not produced on a ledge, present in small thumbed males but absent in large thumbed males. In minor males, the thumb is distally acute, short relative to body length and located on the distal half of the propodus. The dactyl is not centrally toothed. In major males, the thumb is distally acute, longer relative to body length and on the proximal half of the propodus. The dactyl is expanded close to the junction with the propodus but is not centrally toothed.

Adult female:

Antenna 2: large animals with plumose setae on the flagellum and peduncular article 5.

Gnathopod 2: propodus, palm shallowly concave, palmar defining angle acute.

Remarks. Smaller males and females lack the plumose setae on the distal parts of the antenna 2. The long filter setae on antenna 2 are absent or much shorter in the thumbed males than the females or juveniles. Large subadult males have some plumose setae on the flagellum but retain the long setae typical of juveniles and females on the peduncle ( Figs 22–23 ).

The long seta on the anterodistal margin of the gnathopod 1 carpus is usually visible, extending upright or away from the propodus. However, it may also lay flat against the medial face of the propodus, so it is necessary to check for its presence using a fine needle inserted into a rod for grasping or with needle-nosed forceps. Presence of this long seta (or setal cluster), along with lack of apical setae on the telson are key distinguishing characters for J. slatteryi of any size or sex, except from J. carltoni , which also has these character states. Differences from J. carltoni are more in the shape of the gnathopod 1 palm (straighter in J. slatteryi and concave in J. carltoni ), the density of setae on the anterior margin of the basis of gnathopod 2 (more setae in J. slatteryi than J. carltoni ) and in the shape and spination of the gnathopod 2 propodus: slenderer in the female of J. slatteryi with the defining spines tightly clustered and the major form male’s thumb always acute at the tip and not curved posteriorly, while in J. carltoni the female’s defining spines are more dispersed and the major form male’s thumb is more rounded at the tip and curved posteriorly. While J. slatteryi has been found on many coasts, J. carltoni is only known from the Pacific coast of North America. Jassa slatteryi also occurs on the Pacific coast of North America, however, though it has not been found in the same collections as J. carltoni .

Asubset of the specimens described by Hong (1983) as J. falcata were lent for analysis for this study. They had been collected in Deukryang Bay, The Republic of Korea from a settling plate. Major forms ranged from 5.5 to 7.2 mm in body length while minor forms were 3.0– 6.2 mm ( Fig. 24 ). Thumb length was less relative to body size in minor forms than major forms. Aplot of propodus length to body length for the same males, with addition of females from the Deukryang Bay population showed a longer propodus length relative to body length for the adult males than for the females, juvenile and subadult males ( Fig. 25 ). For the adult males that overlapped in body length (5.58–6.41 mm), propodus length did not significantly differ between major and minor form (ANOVA, F = 0.211, p = 0.654, df = 14; major form propodus length 1.863 ± 0.122 mm, n = 7; minor form propodus length 1.830 ± 1.51 mm, n = 8).

Lim and Park (2006) redescribed and illustrated a minor form of J. slatteryi from a collection taken from the screw of a ship in Samcheon-po bay on the south coast of The Republic of Korea. Rumbold et al. (2015a) examined J. slatteryi from Argentina both morphologically and with the CO1 gene, comparing it with J. marmorata and J. staudei . They also provided a photograph of live pigmentation of a subadult male and photographs of various body parts of a minor form thumbed male. Their Fig. 3I is the tip of the maxilliped palp, not the mandible as stated. Pilgrim & Darling (2010) found J. slatteryi , J. marmorata and J. staudei to be unique based on the CO1 gene. Aloan of J. slatteryi that was obtained after Conlan (1990) was of three samples at 11–24 m depth offshore of Rio de Janeiro and Ubatuba, Brazil in 1964–1966. This is the earliest known collection of J. slatteryi on the Atlantic coast of South America (Table 3).

Conlan (1990) cited in error that J. slatteryi occurred in the Galapagos Islands, Ecuador, based on identification of 7 major form males, 3 adult females and 1 juvenile borrowed from the Swedish Museum of Natural History. The collection location was Cumberland Bay, Masatiera, but this is located in Robinson Crusoe Island, Chile (formerly Más a Tierra). The reference by Rumbold et al. (2015a) to J. slatteryi occurring in the Galapagos Islands is therefore also in error. Some other location errors in Conlan (1990) were also found when collections were re-examined for this paper as some specimens of “ J. slatteryi ” on the Pacific North American coast were unrecognized J. morinoi or J. carltoni . Corrected distributions indicate that both J. slatteryi and J. morinoi are indeed trans-hemispheric ( Figs 3–6 ) yet also occur at remote locations along the Pacific North American coast, particularly in British Columbia. Jassa carltoni is only known from the Pacific coast of North America and is now known from British Columbia ( Fig. 10 ; update of Conlan 1990).

Intersexes, having characteristics of both females (setose brood plates) and males (penial papillae and thumbed second gnathopods) were found in Santa Ynez, Eureka Harbor, and Morro Bay, California, Tanabe Bay, Japan and Adelaide, Australia ( Fig. 26 ). The intersexes had small thumbs which could differ in size between right and left gnathopod.

Two species described after the revision by Conlan (1990) are submerged under J. slatteryi : J. cadetta Krapp et al., 2008 and J. trinacriae Krapp et al., 2010 . Jassa cadetta was described by Krapp et al. (2008) based on specimens collected in algae at shallow depth in the Venice Lagoon, Malamocco, Italy (~ 45°22′18ʺN, 12°20′15ʺE). These had a different karyotype and morphology than J. marmorata , which was also found there, and therefore was designated a new species. The possibility that J.cadetta could be J. slatteryi was not considered by the authors, but examination of the types lent by the Museo Civico di Storia Naturale di Verona, Italy showed that their morphology was unmistakeably that of J. slatteryi (Supplementary data file S2). Both J. marmorata and J. slatteryi are common inhabitants of fouling communities in populated areas such as Venice Lagoon ( Table 4 ).

Jassa trinacriae was described based onspecimens collected at Grotta Conza, Sicily (~ 38°11′14″N, 13°16′57″E), at the northern end of the Conca d’Oro, a cave of about 90 m length, 175 m above sea level, and 1 km distant from the sea. Presumably the specimens were in saline water as Jassa is not known from fresh water ( Table 4 ). Additional specimens collected in 1952 from Sampieri, Sicily were also ascribed to this species by Krapp et al. (2010). Aloan of these individuals fromthe same museum as for J. cadetta allowed confirmation that all specimens were clearly J. slatteryi (Supplementary data file S3). Therefore, J. trinacriae is submerged. These specimens are the earliest collection known for the Mediterranean, since the record for Rovinj, Croatia noted in Conlan (1990) had no collection date (Table 3). Navarro-Barranco etal. (2015), Fernandez-Leborans etal. (2016), Fernandez-Gonzalez & Sanchez-Jerez (2017) and Bonifazi et al. (2018) document other Mediterranean locations where J. slatteryi has been confirmed.

Krapp et al. (2010) also described a Jassa sp. from a thermal spring in Fordongianus, Sardinia where the water was 45 °C (54–58 °C at the origin of the spring). Angelone et al. (2005) reported an electrical conductivity of 1,547 µS cm-1, pH 8.40 and Eh 259 mV in this spring, which is in range of that found in seawater. Fordongianus is about 20 km east of the Sardinian west coast. This specimen was also borrowed from the Museo civico di Storia Naturale di Verona, Italy and examined (Supplementary data file S4). Its immature appearance and small size (2.2 mm length) suggest that it is a hatchling. If indeed a species of Jassa , this would be the warmest water recorded ( Table 4 ). The specimenwasslidemountedandthereforecouldnotbemanipulatedtoviewallbodyparts. Conclusivedetermination would require specimens at a more advanced age.

Figures

FIGURE 3. Progressive discovery of Jassa slatteryi from 1850 to 1949. Red dot: identification confirmed by specimen examination; green triangle: literature record (Supplementary Table S1) with identification not confirmed but judged likely to be this species; blue x: suspected or known to be on the hull or interior of a boat or ship.

FIGURE 10. Records of Northern Hemisphere species of Jassa that were found in the eastern and/or western North Pacific and seas. Red dot: identification confirmed by specimen examination; green triangle: literature record (Supplementary Table S1) with identification not confirmed but judged likely to be this species; blue x: suspected or known to be on the hull or interior of a boat or ship.

FIGURE 22. Jassa slatteryi Conlan, 1990. Holotype, adult male, major form, 5.1 mm, NMCC 1987-1068. Moss Landing Harbor, California (36°48’00.7ʺN, 121°47’13.9ʺW), 4 July 1986, K. E. Conlan, coll., station C9, scraping of the bottom of a row boat just below water level, IZ 1986-057 (CMN). Lateral view: whole body and gnathopod 1; dorsal view: telson; other views medial. Scale 0.1 mm. Illustration after Conlan (1990).

FIGURE 23. Jassa slatteryi Conlan, 1990. Paratype, juvenile male, 2.7 mm; paratype, subadult male, 4.5 mm; paratype, minor form male, 3.5 mm; holotype, major form male, 5.1 mm. Moss Landing Harbor, California (36°48’00.7ʺN, 121°47’13.9ʺW), 4 July 1986, K. E. Conlan, coll., station C9, scraping of the bottom of a row boat just below water level, IZ 1986-057 (CMN). Setae omitted except for those around the thumb and spines in order to landmark position changes with growth. Lateral view: second gnathopods; medial view: second antennae. Scale 0.1 mm. Illustration after Conlan (1990).

FIGURE 24. Jassa slatteryi Conlan, 1990. Variation in thumb length relative to body length in a single population of males on a settling plate from Deukryang Bay, The Republic of Korea, May–July 1981, J.S. Hong, coll., A2020.0035 (CMN). Arrows refer to the associated gnathopod illustrations. The subadult male had a thumb visible inside the cuticle, indicating that it would molt next into a thumbed adult. Setae omitted except for those around the thumb and spines in order to landmark position changes with growth. All views lateral. Scale 0.1 mm. Linear regression assumptions failed for all plots. Illustration after Conlan (1990).

FIGURE 25. Jassa slatteryi Conlan, 1990. Variation in gnathopod 2 propodus length relative to body length in a single population of males and females on a settling plate from Deukryang Bay, The Republic of Korea, May–July 1981, J.S. Hong, coll., A2020.0035 (CMN). Linear regression assumptions passed for the subadult male. Linear regression statistics: subadult male, Gn2 propodus length = -0.435 + 0.324 x body length, r2 = 0.916, n = 15.

FIGURE 26. Jassa slatteryi Conlan, 1990. Intersex 1, 4.6 mm; intersex 2, 5.6 mm. Tanabe Bay, Wakayama Prefecture, Japan (33°41ʹN, 135°22ʹE), 2 Apr. 1976, H. Morino, coll., no habitat data, A2020.0036 (CMN). Allotype, adult female, 4.1 mm, NMCC 1987-1069. Moss Landing Harbor, California (36°48’00.7ʺN, 121°47’13.9ʺW), 4 July 1986, K. E. Conlan, coll., sta- tion C9, scraping of the bottom of a row boat just below water level, IZ 1986-057 (CMN). Lateral views: intersex 1 and 2 left gnathopod 2; other views medial. Scale 0.1 mm.

FIGURE 27. Jassa slatteryi Conlan, 1990. Holotype, adult male, major form, 5.1 mm, NMCC 1987-1068. Moss Landing Harbor, California (36°48’00.7ʺN, 121°47’13.9ʺW), 4 July 1986, K. E. Conlan, coll., station C9, scraping of the bottom of a row boat just below water level, IZ 1986-057 (CMN). Mouthparts. Frontal view: upper lip; lateral view: maxilla 1; other views medial. Scale 0.1 mm.