Kyphocalanidae Family - Marine Planktonic Copepods

Calanoida ( Order )	details
Clausocalanoidea ( Superfamily )	details

Abbreviations or symbols

Kyphocalanidae Markhaseva & Schulz, 2009 ( Clausocalanoidea )

Ref.:

Markhaseva & Schulz, 2009 (p.22

Rem.:

1 G. : Kyphocalanus.
For Markhaseva & Schulz (2009, p.22) the new family shares sensory setae on Mx2 and Mxp with a group of clausocalanoidean Bradfordian families including Diaixidae, Parkiidae, Phaennidae, Rostrocalanidae, Scolecitrichidae and Tharybidae. However, Kyphocalanidae is unique among all Bradfordians in possessing various apomorphies.
For the authors (2009, p.37) this family is a derived benthopelagic ‘Bradfordian’ family with a large number of apomorphies shown by the setation of A2, Md, Mx1, Mx2 and Mxp syncoxa. The nfamily does not share the presumed ancestral states of many benthopelagic ‘Bradfordians, viz. the 1st and 2 nd proximal exopodal segment of A2 are equipped with 1 and 3 setae respectively, praecoxal endites of Mxp showing a 1, 2, 3 setation pattern, and a maximum number of 9 setae on Mx1 endopod. However, Kyphocalanidae shares with Rostrocalanidae the absence of brush-like sensory setae on Mx1 endopod (at least 2 and usually 5 to 8 brush-like sensory setae are present in remaining ‘Bradfordians’ families Diaixidae, Parkiidae, Phaennidae ; Scolecittichidae and Tharybidae). Hiowever, Kyphocalanidae does not share synapomorphies of Rostrocalanidae (i.e., a 4-segmebted Md exopod with 4 setae, the presence of 6 worm-like sensory setae on Mx2 endopod), and thus appears not to be closely related to that family. Apparently, Kyphocalanus is an early offshoot of ‘Bradfordian’ ancestors, i.e. a lineage that entirely lacked the development of comparably advanced brush-like setae, while only elementary worm-like sensory setae on Mx1 and Mxp have evolved. The ciomparatively increase in size of worm-like sensory setae in Kyphocalanus suggests that the evolutionary trend of the new genus was apparently connected with far-field detection of food particles and resulted in their strong morphological specialization.

(1) Kyphocalanus Markhaseva & Schulz, 2009

Species, varieties and details

Ref.:

Markhaseva & Schulz, 2009 (p.23

Rem.:

type species: Kyphocalanus atlanticus. 1 sp + 3 without denomitations.
For Markhaseva & Schulz (2009, p.23-24) synapomorphies ( commun possession of derived homologous characters ) for the genus Kyphocalanus are the presence of a knife handle-like basal part of the prosximal seta on the mandibular basis and the maxillule distal basal endite and endopod separate and the distal basal endite bearing 1 seta only (vs. 2-6 setae in other ‘Bradfordians’).
In addition to the characters of the family, the new genus differs from the majority of other ‘Bradfordian’ famolies/genera by the following derived characters :
1- A2 basis without setae, shared with tharybid genus Brodskius Markhaseva & Ferrari (2005), contrasting the presence of 1-2 setae in other ‘Bradfordians’.
2- A2 endopod segment 1 without setae, shared with Pseudophaenna Sars (1902) (genus of unclear familial position) and some species of the tharybid genus Undinella Sars (1900), and contrary to 1-2 setae in other ‘Bradfordians’.
3- A2 endopod segment 2 with fewer than 10 setae, shared with Pseudophaenna, but this segment with 11-15 setae in other ‘Bradfordians’.
4- Maximmule proximal basal endite without setae, shared with Bradfordiella Andronov (2007) (genus of unclear familial position), in contrast to the presence of 2-5 setae in other ‘Bradfordians’.
5- Maxilla proximal praecoxal endite with 2 setae, shared with Rostrocalanus and some species of Bradfordiella, but with 3-5 setae in other ‘Bradfordians’.
6- Maxilla distal praecoxal endite and proximal coxal endite with 2 setae each, shared with some species of Bradfordiella, and contrary to 3 setae in other ‘Bradfordians’.
7- Maxilla distal coxal endite with 2 setae, shared with Phaenna Claus (1863) (Phaennidae), but with 3 setae in other ‘Bradfordians’.
8- Maxilla proximal basal endite with 1 setal element, shared with Bradfordiella, but with 3-4 setal elements in other ‘Bradfordians’.
9- 1 seta on Maxilliped coxal endite, shared with some species of Undinella and Bradfordiella, in contrast to presence of 2 or 3 setae in other ‘Bradfordian genera’.
The similar derived armament of some oral limbs of Kyphocalanus and Bradfordiella is assumed to have arisen in a parallel development and independently, and thus both genera are not considered to be closely related. This is corroborated by apomorphies not shared by Bradfordiella : 1- praecoxal arthrite of Mx1 with 3 setae (vs. 9 in Bradfordiella ; 2- distal coxal endite of Mx2 with 2 setae (vs. 3 setae inBradfordiella ; 3- Mx2 distal basal endite plus endopod with 8 very long and thick, worm-like sensory setae, longer than all sclerotized setae of Mx2 (vs. only 6 short sensory setae of unclear morphology in Bradfordiella.
In addition, Kyphocalanus does not share apomorphies of Bradfordiella : 1- A1 of only 18 segments (vs. 24 in Kyphocalanus) ; 2- Mandibular basis lacking setae (vs. 2 setae in Kyphocalanus) ; 3- Mx1 with coxal and basal endites reduced (vs. these enditese well developed in Kyphocalanus) ; 4- Mxp praecoxal endites of syncoxa lacking setae (with 1, 2, 0 setae in Kyphocalanus).

issued from : E.L. Markhaseva & K. Schulz in Zootaxa, 2009, 2304. [p.37, Fig.11].
Distribution of species of Kyphocalanus in the Atlantic Ocean.
K. atlanticus and K. sp.1: filled black circle; K. sp.2: triangle; K. sp.3: square.