Jassaingens Pfeffer, 1888

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 : 152-153

publication ID

https://doi.org/ 10.11646/zootaxa.4939.1.1

publication LSID

lsid:zoobank.org:pub:F33F42D0-A139-4CE3-97D7-1314C12CF86B

DOI

https://doi.org/10.5281/zenodo.4580606

persistent identifier

https://treatment.plazi.org/id/03B487DA-FF22-D980-C9C8-1F6DFF02FE9C

treatment provided by

Plazi

scientific name

Jassaingens Pfeffer, 1888
status

 

Jassaingens Pfeffer, 1888 View in CoL

( Table 13 View TABLE 13 , Figs 99–101 View FIGURE 99 View FIGURE 100 View FIGURE 101 )

Synonyms: see Conlan (1990).

Diagnosis.

Both sexes:

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

Maxilla 1: with a small cluster of setae at the base of the palp article 1.

Gnathopod 1: basis, anterolateral margin with a few to a full row of short setae along its length which may be slender or spine-like; carpus with a single or small cluster of setae at the anterodistal junction of the propodus (setae about 1/3 of anterior margin length and slightly lateral and medial).

Gnathopod 2: basis with a row of small setae along the anterolateral margin (setal lengths <10% of the basis width); carpus and propodus, setae on the anterior margin short and simple (setal length <basis width).

Pereopods 5–7: propodus expanded anteriorly.

Uropod 1: ventral peduncular spinous process underlying about 40% 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 without plumose setae on the flagellum and peduncular article 5.

Gnathopod 2: propodus, palmar defining spines produced on a ledge, present in both small and large thumbed males.

Adult female:

Antenna 2: without plumose setae on the flagellum and peduncular article 5.

Gnathopod 2: propodus, palmsinuous.

Remarks. All of the thumbed males available for study had relatively short thumbs with the palmar defining spines present and produced on a ledge, suggesting that these spines are not lost even in the largest animals. The antenna 2 setae are long in small juveniles but shorten drastically in the adult males. The expanded propodus of pereopods 5–7 is distinctive, even in the young. This is the largest species known for the genus, with body length at maturity in the specimens available 19.6–24.1 mm for the adult (thumbed) males and 15.3–20.8 mm for the adult females.

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Amphipoda

Family

Ischyroceridae

Genus

Jassa

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