Order LEUCOSOLENIDA Hartman, 1958

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Introduction

2004 INTRODUCTION
Now recognised to include nine families.

Diagnosis

Calcaronea with a skeleton composed of exclusively free spicules, without calcified non-spicular reinforcements. The aquiferous system is asconoid, syconoid, sylleibid, or leuconoid. In the latter case, the radial organisation around a central atrium can generally be detected by a well-formed atrial skeleton tangential to the atrial wall, and/or a subatrial skeleton consisting of subatrial tri- or tetractines with the paired actines tangential to the atrial wall and the unpaired actine perpendicular to it. The post-larval development passes (presumably always) through an olynthus stage.

ID Keys

KEY TO GENERA
(1) Homocoel organisation: all the internal cavities are lined by the choanoderm------------------------------------------2
Heterocoel organisation; with separate choanocyte chambers and an exhalant aquiferous system devoid of choanocytes, with or without a separate inhalant system--------------------------------------------------------------------4

(2) Skeleton contains only diactines-----------------------------------------------------------------------------------Ascyssa
Skeleton composed of diactines, triactines and/or tetractines---------------------------------------------------------------3

(3) Giant longitudinal diactines forming a continuous layer on the external surface-----------------------------Ascute
No giant longitudinal diactines----------------------------------------------------------------------------------Leucosolenia

(4) Skeleton composed exclusively of diactines---------------------------------------------------------------------Sycyssa
Skeleton composed of diactines, triactines and/or tetractines--------------------------------------------------------------5

(5) Sponge body composed of a central atrial tube bearing, at least in its median region, radial tubes lined with choanoderm and ending in conspicuous distal cones that are frequently crowned by tufts of radial diactines------6
Sponge body covered by a cortex supported by tangential spicules----------------------------------------------------10

(6) Elongate radial tubes regularly arranged around the central tube are completely separate from one another; no inhalant aquiferous system, the incurrent water enters directly through pores into the radial choanocyte chambers-------------------------------------------------------------------------------------Sycetta
Radial tubes are coalescent at least in their proximal region------------------------------------------------------------7

(7) Radial tubes are parallel and regularly arranged and are occasionally ramified in their distal part. Radial tubes are coalescent for most of their length, with inhalant canals in between that open to the outer surface between the distal cones through ostia--------------------------------------------------------------------------------------------8
A thin sponge wall consisting of the atrial skeleton supporting irregularly grouped short radial tubes that are coalescent or fused proximally, with free distal cones; each group of tubes communicates through a common opening with the atrial cavity; large irregular inhalant cavities are left between the groups of radial tubes, and frequently reach the outer surface of the central atrial tube-----------------------------------------------Sycantha

(8) The atrial cavity contains an internal tissue network supported by a skeleton of parallel bundles of diactines-------------------------------------------------------------------------Sycandra
No network inside the atrial cavity-----------------------------------------------------------------------------9

(9) Pseudosagittal spicules are present in the distal cones of the radial tubes-----------------------Syconessa
No pseudosagittal spicules in the distal cones-------------------------------------------------------------------Sycon

(10) The whole sponge is covered by a continuous cortex supported by tangential spicules-------------------11
Only the grouped distal cones are covered by a cortical network supported by tangential triactines, leaving large openings to the inhalant cavities, and giving to the external surface a honeycombed aspect-----------------------------------------------Dermatreton

(11) Presence of a distinct layer of subcortical pseudosagittal spicules-----------------------------------------12
Absence of a distinct layer of subcortical pseudosagittal spicules------------------------------------------------17

(12) Inarticulated choanoskeleton composed of the unpaired actines of subatrial spicules and the centripetal paired actines of subcortical pseudosagittal spicules----------------------------------------------------------13
Articulated choanoskeleton, containing few to several rows of tube spicules, which are more or less scattered between the subatrial and subcortical spicules--------------------------------------------------------14

(13) Pseudosagittal spicules are triactines only----------------------------------------------------------Sycettusa
Pseudosagittal spicules are tetractines and triactines---------------------------------------------------Grantilla

(14) Sylleibid or leuconoid organisation--------------------------------------------------Vosmaeropsis
Syconoid organisation---------------------------------------------------------------------------------------15

(15) Without large longitudinal diactines in the cortical or atrial skeleton---------------Grantessa
With large longitudinal diactines in the cortical or atrial skeleton------------------------------------16

(16) Longitudinal diactines in the cortical skeleton only------------------------------------Heteropia
Longitudinal diactines in the cortical and atrial skeleton------------------------------Paraheteropia

(17) Articulated choanoskeleton, with at least some trace of the tube organisation; the majority of spicules have the unpaired actine pointing towards the outer surface of the sponge-------18
Inarticulated choanoskeleton, or choanoskeleton composed of an external inarticulated layer supported by apical actines of cortical tetractines, and an internal layer of scattered triactines and/or tetractines, without any apparent order-------------------------------------------------------34

(18) Without a tangential atrial skeleton substituted by subatrial chiactines (Achramorphidae fam. nov.)-------------------------------------------------------------------------------------------------19
With tangential atrial skeleton composed of triactines and/or tetractines----------------------20

(19) Syconoid organisation------------------------------------------------------------Achramorpha
Sylleibid or leuconoid organisation------------------------------------------------------Megapogon

(20) Spicular tracts in the choanoskeleton (Lelapiidae)-------------------------------------------21
No spicular tracts (Grantiidae)------------------------------------------------------------------------24

(21) Spicular tracts made of 'nail-shaped' triactines, with highly reduced paired actines ----22
Spicular tracts made of diapasons --------------------------------------------------------------------23

(22) Tubular sponge, syconoid or sylleibid organisation, choanoskeleton with short, radially arranged tracts between the distal parts of the radial tubes------------------------ Grantiopsis
Massive sponge with a thick wall containing large diactines, choanoskeleton with long tracts in an approximately radial arrangement----------------------------------------------------------Kebira

(23) Cortex composed of giant longitudinal diactines, which do not invade the choanoskeleton -------------------------------------------------------------------------------------------------Paralelapia
Giant diactines in the choanoskeleton -------------------------------------------------------Lelapia

(24) Absence of longitudinal diactine in the atrial and/or cortical skeleton--------------------25
Presence of longitudinal diactines in the atrial and/or cortical skeleton------------------------29

(25) Syconoid organisation---------------------------------------------------------------------------26
Sylleibid or leuconoid organisation------------------------------------------------------------------27

(26) Diameter of the osculum smaller than that of the atrium--------------------------Grantia
Diameter of the osculum larger than that of the atrium: pedunculate calyciform sponge with a thin folded wall--------------------------------------------------------------------------Teichonopsis

(27) Septa with a specific skeleton of minute triactines within the atrial cavity--------Leucettaga
No septa within the atrial cavity------------------------------------------------------------------28

(28) Cortex composed of triactines and possibly diactines, which protrude from the cortex making it hispid-------------------------------------------------------------------------Leucandra
Cortex with triactines and tetractines---------------------------------------------Leucandrilla

(29) Leuconoid organisation--------------------------------------------------------Aphroceras
Syconoid organisation-----------------------------------------------------------------------------30

(30) Sponge with individual syconoid tubes or an arborescent cormus composed of separate tubes------------------------------------------------------------------------------------------------31
Massive cormus composed of coalescent syconoid units, covered by a common cortex----------------------------------------------------------------------------------Synute

(31) Longitudinal diactines present only in the cortex--------------------------------------32
Longitudinal diactines present in the atrial skeleton----------------------------------------33

(32) Tufts of thin radial diactines decorate the distal parts of the radial tubes, and cross the cortex between the longitudinal diactines---------------------------------------------Sycute
No tufts of radial diactines-------------------------------------------------------------------Ute

(33) Longitudinal diactines present only in the atrial skeleton----------------Sycodorus
Longitudinal diactines present both in the atrial and the cortical skeleton---------------------------Amphiute

(34) Giant cortical tetractines (Amphoriscidae)---------------------------------------------35
No giant cortical tetractines (Jenkinidae)----------------------------------------------------37

(35) Syconoid organisation.----------------------------------------------------Amphoriscus
Sylleibid or leuconoid organisation-----------------------------------------------------------36

(36) Inarticulated choanoskeleton; scattered spicules occasionally between subcortical and subatrial layers------------------------------------------------------Leucilla
Choanoskeleton divided in two parts: the external part has an inarticulated organisation, while the internal one is intercalated between the subatrial spicules and the atrial skeleton, and is supported by scattered triactines and/or tetractines-------------------------------Paraleucilla

(37) Syconoid organisation-------------------------------------------------------38
Sylleibid or leuconoid organisation---------------------------------------------------------40

(38) Thin cortical skeleton, composed of one to several layers of triactines-------------------------Breitfussia
Reinforced cortical skeleton-----------------------------------------------------------------39

(39) Skeleton reinforced with giant tangential triactines, which are also scattered in the choanoskeleton--------------------------------------------------------------------Anamixilla
Reinforced skeleton with longitudinal diactines---------------------------------Uteopsis

(40) Without scattered spicules in the choanoskeleton---------------------------------41
With scattered spicules in the choanoskeleton, smaller than those of the cortex, and without defined position------------------------------------------Polejaevia

(41) Sponge growing as small individual tubes---------------------------------Jenkina
Sponge forming a large cormus composed of copiously anastomosed and ramified tubes----------------------------------------------Leucascandra

Diagnosis References

Borojevic, R., Boury-Esnault, N., Manuel, M. & Vacelet, J. 2002. Order Leucosolenida Hartman, 1958. pp. 1157-1184 in Hooper, J.N.A. & Soest, R.W.M. Van (eds). Systema Porifera. A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 2. [1157]

General References

Borojevic, R., Boury-Esnault, N., Manuel, M. & Vacelet, J. 2002. Order Leucosolenida Hartman, 1958. pp. 1157-1184 in Hooper, J.N.A. & Soest, R.W.M. Van (eds). Systema Porifera. A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 2. (1157)

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